Sample records for observed cloud cover

  1. A Survey of Changes in Cloud Cover and Cloud Types over Land from Surface Observations, 197196

    E-Print Network [OSTI]

    Hochberg, Michael

    of their effects on solar radiation, terrestrial radiation, and precipitation. These effects depend on cloud height, and the season of the year and time of day. The effect of clouds on the earth's radiation budget, the "cloud to be a useful classification in studies of cloud processes (Houze 1993). The climatic effects of clouds further

  2. Variations in Cloud Cover and Cloud Types over the Ocean from Surface Observations, 19542008

    E-Print Network [OSTI]

    Hochberg, Michael

    ). MSC therefore have a cooling ef- fect on climate [negative cloud radiative effect (CRE)]. Randall et in climate, affecting both radiation fluxes and latent heat fluxes, but the various cloud types affect marine. By contrast, high (cirriform) clouds are thinner and colder, so their longwave effect dominates, giving them

  3. Changes in Cloud Cover and Cloud Types Over the Ocean from Surface

    E-Print Network [OSTI]

    Hochberg, Michael

    Total cloud cover 54 68 Clear sky (frequency) 22 3 #12;Low Clouds & Solar Radiation Low clouds scatterChanges in Cloud Cover and Cloud Types Over the Ocean from Surface Observations, 1954-2008 Ryan This produces a weak net warming effect in the atmosphere, since more radiation comes in, and less goes out

  4. Decomposing aerosol cloud radiative effects into cloud cover, liquid water path and Twomey components

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Decomposing aerosol cloud radiative effects into cloud cover, liquid water path and Twomey interactions radiative effects, i.e., the cloud cover, liquid water path (LWP) and cloud drop radius (Twomey negative radiative forcing on the global scale, mainly due to the cloud cover effect. © 2013 Elsevier B

  5. CLOUD COVER REPORTING BIAS AT MAJOR AIRPORTS Richard Perez

    E-Print Network [OSTI]

    Perez, Richard R.

    CLOUD COVER REPORTING BIAS AT MAJOR AIRPORTS Richard Perez Joshua A. Bonaventura-Sparagna & Marek Kmiecik ASRC, SUNY, Albany, NY Ray George & David Renné NREL, Golden, CO ABSTRACT Cloud cover has been generated all or in part from cloud cover measurements [1,2]. This paper presents evidence

  6. First observations of tracking clouds using scanning ARM cloud radars

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Borque, Paloma; Giangrande, Scott; Kollias, Pavlos

    2014-12-01T23:59:59.000Z

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud fieldmore »and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.« less

  7. First observations of tracking clouds using scanning ARM cloud radars

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Borque, Paloma [McGill Univ., Montreal, QC (Canada); Giangrande, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Kollias, Pavlos [McGill Univ., Montreal, QC (Canada)

    2014-12-01T23:59:59.000Z

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.

  8. Enhancement of cloud cover and suppression of nocturnal drizzle in stratocumulus polluted by haze

    E-Print Network [OSTI]

    to amplify the negative radiative forcing by increasing cloud cover and cloud water [Albrecht, 1989]. [3] We in ship tracks [Ackerman et al., 2000]. Evidence for secondary effects is ambiguous. Cloud cover is seenEnhancement of cloud cover and suppression of nocturnal drizzle in stratocumulus polluted by haze A

  9. Cloud cover increase with increasing aerosol absorptivity: A counterexample to the conventional semidirect aerosol effect

    E-Print Network [OSTI]

    humidity. The net effect is more low cloud cover with increasing aerosol absorption. The higher specific by dust radiative heating. Although in some areas our model exhibits a reduction of low cloud cover due are expected to have a similar effect. Citation: Perlwitz, J., and R. L. Miller (2010), Cloud cover increase

  10. CLOUD, DRIZZLE, AND TURBULENCE OBSERVATIONS IN MARINE STRATOCUMULUS CLOUDS IN THE AZORES

    E-Print Network [OSTI]

    CLOUD, DRIZZLE, AND TURBULENCE OBSERVATIONS IN MARINE STRATOCUMULUS CLOUDS IN THE AZORES Jasmine at the Azores provided a unique, long-term record (May 2009 to December 2010) of cloud observations in a regime dominated by low-level stratiform clouds. First, a comprehensive cloud classification scheme that utilizes

  11. Electron Cloud observation in the LHC

    E-Print Network [OSTI]

    Rumolo, G; Baglin, V; Bartosik, H; Biancacci, N; Baudrenghien, P; Bregliozzi, G; Chiggiato, P; Claudet, S; De Maria, R; Esteban-Muller, J; Favier, M; Hansen, C; Höfle, W; Jimenez, J M; Kain, V; Lanza, G; Li, K S B; Maury Cuna, G H I; Métral, E; Papotti, G; Pieloni, T; Roncarolo, F; Salvant, B; Shaposhnikova, E N; Steinhagen, R J; Tavian, L J; Valuch, D; Venturini Delsolaro, W; Zimmermann, F; Iriso, U; Dominguez, O; Koukovini-Platia, E; Mounet, N; Zannini, C; Bhat, C M

    2011-01-01T23:59:59.000Z

    Operation of LHC with bunch trains at different spacings has revealed the formation of an electron cloud inside the machine. The main observations of electron cloud build up are the pressure rise measured at the vacuum gauges in the warm regions, as well as the increase of the beam screen temperature in the cold regions due to an additional heat load. The effects of the electron cloud were also visible as instability and emittance growth affecting the last bunches of longer trains, which could be improved running with higher chromaticity or larger transverse emittances. A summary of the 2010 and 2011 observations and measurements and a comparison with models will be presented. The efficiency of scrubbing to improve the machine running performance will be briefly discussed.

  12. Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical modeling of drizzle evolution

    E-Print Network [OSTI]

    Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical I, the influence of cloud microphysics and dynamics on the shape of cloud radar Doppler spectra in warm stratiform clouds was discussed. The traditional analysis of radar Doppler moments was extended

  13. ARM: Fractional cloud cover, clear-sky and all-sky shortwave flux for each of 25 individual SGP facilities.

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Gaustad, Krista; Gaustad, Krista; McFarlane, Sally; McFarlane, Sally

    Fractional cloud cover, clear-sky and all-sky shortwave flux for each of 25 individual SGP facilities.

  14. SCANNING CLOUD RADAR OBSERVATIONS AT AZORES: PRELIMINARY 3D CLOUD PRODUCTS

    E-Print Network [OSTI]

    SCANNING CLOUD RADAR OBSERVATIONS AT AZORES: PRELIMINARY 3D CLOUD PRODUCTS P. Kollias, I. Jo, A, NY www.bnl.gov ABSTRACT The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers

  15. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during

    E-Print Network [OSTI]

    Zuidema, Paquita

    /crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterizationIntercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud

  16. Aircraft Observations of Sub-cloud Aerosol and Convective Cloud Physical Properties

    E-Print Network [OSTI]

    Axisa, Duncan

    2011-02-22T23:59:59.000Z

    This research focuses on aircraft observational studies of aerosol-cloud interactions in cumulus clouds. The data were collected in the summer of 2004, the spring of 2007 and the mid-winter and spring of 2008 in Texas, central Saudi Arabia...

  17. An annual cycle of Arctic cloud characteristics observed by radar and lidar at SHEBA

    E-Print Network [OSTI]

    Shupe, Matthew

    distribution of cloud boundary heights, and occurrence of liquid phase in clouds are determined from radar-observed clouds containing liquid was 73% for the year. The least amount of liquid water phase was observed during-detected clouds. Liquid was distributed in a combination of all-liquid and mixed phase clouds, and was detected

  18. LES Simulations of Roll Clouds Observed During Mixed- Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Greenberg, S.D.; Harrington, J.Y.; Prenni, A.; DeMott, P.

    2005-03-18T23:59:59.000Z

    Roll clouds, and associated roll convection, are fairly common features of the atmospheric boundary layer. While these organized cumuliform clouds are found over many regions of the planet, they are quite ubiquitous near the edge of the polar ice sheets. In particular, during periods of off-ice flow, when cold polar air flows from the ice pack over the relatively warm ocean water, strong boundary layer convection develops along with frequent rolls. According to Bruemmer and Pohlman (2000), most of the total cloud cover in the Arctic is due to roll clouds. In an effort to examine the influences of mixed-phase microphysics on the boundary layer evolution of roll clouds during off-ice flow, Olsson and Harrington (2000) used a 2D mesoscale model coupled to a bulk microphysical scheme (see Section 2). Their results showed that mixed-phase clouds produced more shallow boundary layers with weaker turbulence than liquid-phase cases. Furthermore, their results showed that because of th e reduced turbulent drag on the atmosphere in the mixed-phase case, regions of mesoscale divergence in the marginal ice-zone were significantly affected. A follow-up 2D study (Harrington and Olsson 2001) showed that the reduced turbulent intensity in mixed-phase cases was due to precipitation. Ice precipitation caused downdraft stabilization which fed back and caused a reduction in the surface heat fluxes. In this work, we extend the work of Olsson and Harrington (2000) and Harrington and Olsson (2001) by examining the impacts of ice microphysics on roll convection. We will present results that illustrate how microphysics alters roll cloud structure and dynamics.

  19. Climatological data for clouds over the globe from surface observations, 1982--1991: The total cloud edition

    SciTech Connect (OSTI)

    Hahn, C.J. [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences] [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences; Warren, S.G. [Washington Univ., Seattle, WA (United States). Dept. of Atmospheric Sciences] [Washington Univ., Seattle, WA (United States). Dept. of Atmospheric Sciences; London, J. [Colorado Univ., Boulder, CO (United States). Dept. of Astrophysical, Planetary, and Atmospheric Sciences] [Colorado Univ., Boulder, CO (United States). Dept. of Astrophysical, Planetary, and Atmospheric Sciences

    1994-10-01T23:59:59.000Z

    Routine, surface synoptic weather reports from ships and land stations over the entire globe, for the ten-year period December 1981 through November 1991, were processed for total cloud cover and the frequencies of occurrence of clear sky, precipitation, and sky-obscured due to fog. Archived data, consisting of various annual, seasonal and monthly averages, are provided in grid boxes that are typically 2.5{degrees} {times} 2.5{degrees} for land and 5{degrees} {times} 5{degrees} for ocean. Day and nighttime averages are also given separately for each season. Several derived quantities, such as interannual variations and annual and diurnal harmonics, are provided as well. This data set incorporates an improved representation of nighttime cloudiness by utilizing only those nighttime observations for which the illuminance due to moonlight exceeds a specified threshold. This reduction in the night-detection bias increases the computed global average total cloud cover by about 2%. The impact on computed diurnal cycles is even greater, particularly over the oceans where is found, in contrast to previous surface-based climatologies, that cloudiness is often greater at night than during the day.

  20. Dust properties inside molecular clouds from coreshine modeling and observations

    E-Print Network [OSTI]

    Lefèvre, Charlène; Juvela, Mika; Paladini, Roberta; Lallement, Rosine; Marshall, D J; Andersen, Morten; Bacmann, Aurore; Mcgee, Peregrine M; Montier, Ludovic; Noriega-Crespo, Alberto; Pelkonen, V -M; Ristorcelli, Isabelle; Steinacker, Jürgen

    2014-01-01T23:59:59.000Z

    Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\\mu$m that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend of surface bright- nesses and intensity ratios of both coreshine and near-infrared observation...

  1. Parameterizing the Difference in Cloud Fraction Defined by Area and by Volume as Observed with Radar and Lidar

    E-Print Network [OSTI]

    Reading, University of

    partially cloudy grid boxes by weighting clear and cloudy fluxes by the fractional area of cloud cover (Ca cloud cover from 53% to 63%, and so is of similar importance to the cloud overlap assumption. A simple for calculating the radiative effect of cloud (Stephens 1984; Edwards and Slingo 1996) and the representation

  2. ARM: Gridded (0.25 x 0.25 lat/lon) fractional cloud cover, clear-sky and all-sky shortwave flux over the SGP site.

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Gaustad, Krista; Gaustad, Krista; McFarlane, Sally; McFarlane, Sally

    Gridded (0.25 x 0.25 lat/lon) fractional cloud cover, clear-sky and all-sky shortwave flux over the SGP site.

  3. Electron cloud observations at the ISIS Proton Synchrotron

    E-Print Network [OSTI]

    Pertica, A

    2013-01-01T23:59:59.000Z

    The build up of electron clouds inside a particle accelerator vacuum chamber can produce strong transverse and longitudinal beam instabilities which in turn can lead to high levels of beam loss often requiring the accelerator to be run below its design specification. To study the behaviour of electron clouds at the ISIS Proton Synchrotron, a Micro-Channel Plate (MCP) based electron cloud detector has been developed. The detector is based on the Retarding Field Analyser (RFA) design and consists of a retarding grid, which allows energy analysis of the electron signal, and a MCP assembly placed in front of the collector plate. The MCP assembly provides a current gain over the range 300 to 25K, thereby increasing the signal to noise ratio and dynamic range of the measurements. This paper presents the first electron cloud observations at the ISIS Proton Synchrotron. These results are compared against signals from a beam position monitor and a fast beam loss monitor installed at the same location.

  4. QUANTIFYING OBSERVATIONAL PROJECTION EFFECTS USING MOLECULAR CLOUD SIMULATIONS

    SciTech Connect (OSTI)

    Beaumont, Christopher N. [Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Offner, Stella S.R. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Shetty, Rahul; Glover, Simon C. O. [Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Goodman, Alyssa A., E-mail: beaumont@ifa.hawaii.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2013-11-10T23:59:59.000Z

    The physical properties of molecular clouds are often measured using spectral-line observations, which provide the only probes of the clouds' velocity structure. It is hard, though, to assess whether and to what extent intensity features in position-position-velocity (PPV) space correspond to 'real' density structures in position-position-position (PPP) space. In this paper, we create synthetic molecular cloud spectral-line maps of simulated molecular clouds, and present a new technique for measuring the reality of individual PPV structures. Using a dendrogram algorithm, we identify hierarchical structures in both PPP and PPV space. Our procedure projects density structures identified in PPP space into corresponding intensity structures in PPV space and then measures the geometric overlap of the projected structures with structures identified from the synthetic observation. The fractional overlap between a PPP and PPV structure quantifies how well the synthetic observation recovers information about the three-dimensional structure. Applying this machinery to a set of synthetic observations of CO isotopes, we measure how well spectral-line measurements recover mass, size, velocity dispersion, and virial parameter for a simulated star-forming region. By disabling various steps of our analysis, we investigate how much opacity, chemistry, and gravity affect measurements of physical properties extracted from PPV cubes. For the simulations used here, which offer a decent, but not perfect, match to the properties of a star-forming region like Perseus, our results suggest that superposition induces a ?40% uncertainty in masses, sizes, and velocity dispersions derived from {sup 13}CO (J = 1-0). As would be expected, superposition and confusion is worst in regions where the filling factor of emitting material is large. The virial parameter is most affected by superposition, such that estimates of the virial parameter derived from PPV and PPP information typically disagree by a factor of ?2. This uncertainty makes it particularly difficult to judge whether gravitational or kinetic energy dominate a given region, since the majority of virial parameter measurements fall within a factor of two of the equipartition level ? ? 2.

  5. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part II: Multi-layered cloud

    SciTech Connect (OSTI)

    Morrison, H; McCoy, R B; Klein, S A; Xie, S; Luo, Y; Avramov, A; Chen, M; Cole, J; Falk, M; Foster, M; Genio, A D; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; McFarquhar, G; Poellot, M; Shipway, B; Shupe, M; Sud, Y; Turner, D; Veron, D; Walker, G; Wang, Z; Wolf, A; Xu, K; Yang, F; Zhang, G

    2008-02-27T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a deep, multi-layered, mixed-phase cloud system observed during the ARM Mixed-Phase Arctic Cloud Experiment. This cloud system was associated with strong surface turbulent sensible and latent heat fluxes as cold air flowed over the open Arctic Ocean, combined with a low pressure system that supplied moisture at mid-level. The simulations, performed by 13 single-column and 4 cloud-resolving models, generally overestimate the liquid water path and strongly underestimate the ice water path, although there is a large spread among the models. This finding is in contrast with results for the single-layer, low-level mixed-phase stratocumulus case in Part I of this study, as well as previous studies of shallow mixed-phase Arctic clouds, that showed an underprediction of liquid water path. The overestimate of liquid water path and underestimate of ice water path occur primarily when deeper mixed-phase clouds extending into the mid-troposphere were observed. These results suggest important differences in the ability of models to simulate Arctic mixed-phase clouds that are deep and multi-layered versus shallow and single-layered. In general, models with a more sophisticated, two-moment treatment of the cloud microphysics produce a somewhat smaller liquid water path that is closer to observations. The cloud-resolving models tend to produce a larger cloud fraction than the single-column models. The liquid water path and especially the cloud fraction have a large impact on the cloud radiative forcing at the surface, which is dominated by the longwave flux for this case.

  6. Observation of Magnetic Resonances in Electron Clouds in a Positron Storage Ring

    SciTech Connect (OSTI)

    Pivi, M.T.F.; Ng, J.S.T.; Cooper, F.; Kharakh, D.; King, F.; Kirby, R.E.; Kuekan, B.; Spencer, Cherrill M.; Raubenheimer, T.O.; Wang, L.F.; /SLAC

    2011-08-24T23:59:59.000Z

    The first experimental observation of magnetic resonances in electron clouds is reported. The resonance was observed as a modulation in cloud intensity for uncoated as well as TiN-coated aluminum surfaces in the positron storage ring of the PEP-II collider at SLAC. Electron clouds frequently arise in accelerators of positively charged particles, and severely impact the machines performance. The TiN coating was found to be an effective remedy, reducing the cloud intensity by three orders of magnitude.

  7. Observation of cooperative Mie scattering from an ultracold atomic cloud

    SciTech Connect (OSTI)

    Bender, H.; Stehle, C.; Slama, S.; Zimmermann, C. [Physikalisches Institut, Eberhardt-Karls-Universitaet Tuebingen, D-72076 Tuebingen (Germany); Kaiser, R. [Institut Non Lineaire de Nice, CNRS, Universite de Nice Sophia-Antipolis, F-06560 Valbonne (France); Piovella, N. [Dipartimento di Fisica, Universita Degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy); Courteille, Ph. W. [Physikalisches Institut, Eberhardt-Karls-Universitaet Tuebingen, D-72076 Tuebingen (Germany); Institut Non Lineaire de Nice, CNRS, Universite de Nice Sophia-Antipolis, F-06560 Valbonne (France); Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, 13560-970 Sao Carlos, SP (Brazil)

    2010-07-15T23:59:59.000Z

    Scattering of light at a distribution of scatterers is an intrinsically cooperative process, which means that the scattering rate and the angular distribution of the scattered light are essentially governed by bulk properties of the distribution, such as its size, shape, and density, although local disorder and density fluctuations may have an important impact on the cooperativity. Via measurements of the radiation pressure force exerted by a far-detuned laser beam on a very small and dense cloud of ultracold atoms, we are able to identify the respective roles of superradiant acceleration of the scattering rate and of Mie scattering in the cooperative process. They lead, respectively, to a suppression or an enhancement of the radiation pressure force. We observe a maximum in the radiation pressure force as a function of the phase shift induced in the incident laser beam by the cloud's refractive index. The maximum marks the borderline of the validity of the Rayleigh-Debye-Gans approximation from a regime, where Mie scattering is more complex. Our observations thus help to clarify the intricate relationship between Rayleigh scattering of light at a coarse-grained ensemble of individual scatterers and Mie scattering at the bulk density distribution.

  8. Summertime Arctic Clouds observed during SHEBA Paquita Zuidema

    E-Print Network [OSTI]

    Zuidema, Paquita

    understanding the underlying cloud processes (that impact the cloud optical depth). With the goal in mind consistently southerly and warm.The ice melt rate was directly measured to be 2.3-2.5 cm/day from gauges). The responsive surface melting during July suggests not only a high Sun angle,but also low cloud optical depths

  9. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    SciTech Connect (OSTI)

    Klein, S A; McCoy, R B; Morrison, H; Ackerman, A; Avramov, A; deBoer, G; Chen, M; Cole, J; DelGenio, A; Golaz, J; Hashino, T; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; Luo, Y; McFarquhar, G; Menon, S; Neggers, R; Park, S; Poellot, M; von Salzen, K; Schmidt, J; Sednev, I; Shipway, B; Shupe, M; Spangenberg, D; Sud, Y; Turner, D; Veron, D; Falk, M; Foster, M; Fridlind, A; Walker, G; Wang, Z; Wolf, A; Xie, S; Xu, K; Yang, F; Zhang, G

    2008-02-27T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics indicate that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is some evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics. This case study, which has been well observed from both aircraft and ground-based remote sensors, could be a benchmark for model simulations of mixed-phase clouds.

  10. Observations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget along 208S

    E-Print Network [OSTI]

    Yuter, Sandra

    of cloud properties and drizzle statistics, and the effect of stratocumulus clouds on surface radiationObservations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget gradients in boundary layer and cloud vertical structure, surface radiation and cloud radiative forcing

  11. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during SHEBA/FIRE-ACE

    SciTech Connect (OSTI)

    Morrison, H.; Zuidema, Paquita; Ackerman, Andrew; Avramov, Alexander; de Boer, Gijs; Fan, Jiwen; Fridlind, Ann; Hashino, Tempei; Harrington, Jerry Y.; Luo, Yali; Ovchinnikov, Mikhail; Shipway, Ben

    2011-06-16T23:59:59.000Z

    An intercomparison of six cloud-resolving and large-eddy simulation models is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud gathered on 7 May, 1998 from the Surface Heat Budget of Arctic Ocean (SHEBA) and First ISCCP Regional Experiment - Arctic Cloud Experiment (FIRE-ACE). Ice nucleation is constrained in the simulations in a way that holds the ice crystal concentration approximately fixed, with two sets of sensitivity runs in addition to the baseline simulations utilizing different specified ice nucleus (IN) concentrations. All of the baseline and sensitivity simulations group into two distinct quasi-steady states associated with either persistent mixed-phase clouds or all-ice clouds after the first few hours of integration, implying the existence of multiple equilibria. These two states are associated with distinctly different microphysical, thermodynamic, and radiative characteristics. Most but not all of the models produce a persistent mixed-phase cloud qualitatively similar to observations using the baseline IN/crystal concentration, while small increases in the IN/crystal concentration generally lead to rapid glaciation and conversion to the all-ice state. Budget analysis indicates that larger ice deposition rates associated with increased IN/crystal concentrations have a limited direct impact on dissipation of liquid in these simulations. However, the impact of increased ice deposition is greatly enhanced by several interaction pathways that lead to an increased surface precipitation flux, weaker cloud top radiative cooling and cloud dynamics, and reduced vertical mixing, promoting rapid glaciation of the mixed-phase cloud for deposition rates in the cloud layer greater than about 1-2x10-5 g kg-1 s-1. These results indicate the critical importance of precipitation-radiative-dynamical interactions in simulating cloud phase, which have been neglected in previous fixed-dynamical parcel studies of the cloud phase parameter space. Large sensitivity to the IN/crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterization in models.

  12. Investigation of a cloud-cover modification to SPCTRAL2, SERI's simple model for cloudless-sky, spectral solar irradiance

    SciTech Connect (OSTI)

    Bird, R.E.; Riordan, C.J.; Myers, D.R.

    1987-06-01T23:59:59.000Z

    This report summarizes the investigation of a cloud-cover modification to SPCTRAL2, SERI's simple model for cloudless-sky, spectral solar irradiance. Our approach was to develop a modifier that relies on commonly acquired meteorological and broadband-irradiance data rather than detailed cloud properties that are generally not available. The method was to normalize modeled, cloudless-sky spectral irradiance to a measured broadband-irradiance value under cloudy skies, and then to compare the normalized, modeled data with measured spectral-irradiance data to empirically derive spectral modifiers that improve the agreement between modeled and measured data. Results indicate the possible form of the spectral corrections; however, we must analyze additional data to develop a spectral transmission function for cloudy-sky conditions.

  13. STATUS, EVALUATION AND NEW DEVELOPMENTS IN THE AUTOMATED CLOUD OBSERVATIONS IN THE NETHERLANDS

    E-Print Network [OSTI]

    Wauben, Wiel

    STATUS, EVALUATION AND NEW DEVELOPMENTS IN THE AUTOMATED CLOUD OBSERVATIONS IN THE NETHERLANDS Wiel infrared radiometer. The evaluation of the automated cloud observations will address: (i) effects every 10 minutes. In 2006 and 2007 LD-40 sensors will replace the ceilometers at 7 Dutch Royal Air Force

  14. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    SciTech Connect (OSTI)

    Klein, Stephen A.; McCoy, Renata B.; Morrison, Hugh; Ackerman, Andrew S.; Avramov, Alexander; de Boer, Gijs; Chen, Mingxuan; Cole, Jason N.S.; Del Genio, Anthony D.; Falk, Michael; Foster, Michael J.; Fridlind, Ann; Golaz, Jean-Christophe; Hashino, Tempei; Harrington, Jerry Y.; Hoose, Corinna; Khairoutdinov, Marat F.; Larson, Vincent E.; Liu, Xiaohong; Luo, Yali; McFarquhar, Greg M.; Menon, Surabi; Neggers, Roel A. J.; Park, Sungsu; Poellot, Michael R.; Schmidt, Jerome M.; Sednev, Igor; Shipway, Ben J.; Shupe, Matthew D.; Spangenberg, Douglas A.; Sud, Yogesh C.; Turner, David D.; Veron, Dana E.; von Salzen, Knut; Walker, Gregory K.; Wang, Zhien; Wolf, Audrey B.; Xie, Shaocheng; Xu, Kuan-Man; Yang, Fanglin; Zhang, Gong

    2009-02-02T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed average liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the average mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics suggest that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics.

  15. Testing Cloud Microphysics Parameterizations in NCAR CAM5 with ISDAC and M-PACE Observations

    SciTech Connect (OSTI)

    Liu, Xiaohong; Xie, Shaocheng; Boyle, James; Klein, Stephen A.; Shi, Xiangjun; Wang, Zhien; Lin, Wuyin; Ghan, Steven J.; Earle, Michael; Liu, Peter; Zelenyuk, Alla

    2011-12-24T23:59:59.000Z

    Arctic clouds simulated by the NCAR Community Atmospheric Model version 5 (CAM5) are evaluated with observations from the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Indirect and Semi-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its North Slope of Alaska site in April 2008 and October 2004, respectively. Model forecasts for the Arctic Spring and Fall seasons performed under the Cloud- Associated Parameterizations Testbed (CAPT) framework generally reproduce the spatial distributions of cloud fraction for single-layer boundary layer mixed-phase stratocumulus, and multilayer or deep frontal clouds. However, for low-level clouds, the model significantly underestimates the observed cloud liquid water content in both seasons and cloud fraction in the Spring season. As a result, CAM5 significantly underestimates the surface downward longwave (LW) radiative fluxes by 20-40 W m-2. The model with a new ice nucleation parameterization moderately improves the model simulations by increasing cloud liquid water content in mixed-phase clouds through the reduction of the conversion rate from cloud liquid to ice by the Wegener-Bergeron- Findeisen (WBF) process. The CAM5 single column model testing shows that change in the homogeneous freezing temperature of rain to form snow from -5 C to -40 C has a substantial impact on the modeled liquid water content through the slowing-down of liquid and rain-related processes. In contrast, collections of cloud ice by snow and cloud liquid by rain are of minor importance for single-layer boundary layer mixed-phase clouds in the Arctic.

  16. Testing cloud microphysics parameterizations in NCAR CAM5 with ISDAC and M-PACE observations

    SciTech Connect (OSTI)

    Liu X.; Lin W.; Xie, S.; Boyle, J.; Klein, S. A.; Shi, X.; Wang, Z.; Ghan, S. J.; Earle, M.; Liu, P. S. K.; Zelenyuk, A.

    2011-12-24T23:59:59.000Z

    Arctic clouds simulated by the National Center for Atmospheric Research (NCAR) Community Atmospheric Model version 5 (CAM5) are evaluated with observations from the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Indirect and Semi-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its North Slope of Alaska site in April 2008 and October 2004, respectively. Model forecasts for the Arctic spring and fall seasons performed under the Cloud-Associated Parameterizations Testbed framework generally reproduce the spatial distributions of cloud fraction for single-layer boundary-layer mixed-phase stratocumulus and multilayer or deep frontal clouds. However, for low-level stratocumulus, the model significantly underestimates the observed cloud liquid water content in both seasons. As a result, CAM5 significantly underestimates the surface downward longwave radiative fluxes by 20-40 W m{sup -2}. Introducing a new ice nucleation parameterization slightly improves the model performance for low-level mixed-phase clouds by increasing cloud liquid water content through the reduction of the conversion rate from cloud liquid to ice by the Wegener-Bergeron-Findeisen process. The CAM5 single-column model testing shows that changing the instantaneous freezing temperature of rain to form snow from -5 C to -40 C causes a large increase in modeled cloud liquid water content through the slowing down of cloud liquid and rain-related processes (e.g., autoconversion of cloud liquid to rain). The underestimation of aerosol concentrations in CAM5 in the Arctic also plays an important role in the low bias of cloud liquid water in the single-layer mixed-phase clouds. In addition, numerical issues related to the coupling of model physics and time stepping in CAM5 are responsible for the model biases and will be explored in future studies.

  17. Cloud Effects on Radiative Heating Rate Profiles over Darwin using ARM and A-train Radar/Lidar Observations

    SciTech Connect (OSTI)

    Thorsen, Tyler J.; Fu, Qiang; Comstock, Jennifer M.

    2013-06-11T23:59:59.000Z

    Observations of clouds from the ground-based U.S. Department of Energy Atmospheric Radiation Measurement program (ARM) and satellite-based A-train are used to compute cloud radiative forcing profiles over the ARM Darwin, Australia site. Cloud properties are obtained from both radar (the ARM Millimeter Cloud Radar (MMCR) and the CloudSat satellite in the A-train) and lidar (the ARM Micropulse lidar (MPL) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite in the A-train) observations. Cloud microphysical properties are taken from combined radar and lidar retrievals for ice clouds and radar only or lidar only retrievals for liquid clouds. Large, statistically significant differences of up to 1.43 K/day exist between the mean ARM and A-train net cloud radiative forcing profiles. The majority of the difference in cloud radiative forcing profiles is shown to be due to a large difference in the cloud fraction above 12 km. Above this altitude the A-train cloud fraction is significantly larger because more clouds are detected by CALIPSO than by the ground-based MPL. It is shown that the MPL is unable to observe as many high clouds as CALIPSO due to being more frequently attenuated and a poorer sensitivity even in otherwise clear-sky conditions. After accounting for cloud fraction differences and instrument sampling differences due to viewing platform we determined that differences in cloud radiative forcing due to the retrieved ice cloud properties is relatively small. This study demonstrates that A-train observations are better suited for the calculation cloud radiative forcing profiles. In addition, we find that it is necessary to supplement CloudSat with CALIPSO observations to obtain accurate cloud radiative forcing profiles since a large portion of clouds at Darwin are detected by CALIPSO only.

  18. Observable consequences of cold clouds as dark matter

    E-Print Network [OSTI]

    E. Kerins; J. Binney; J. Silk

    2002-01-10T23:59:59.000Z

    Cold, dense clouds of gas have been proposed as baryonic candidates for the dark matter in Galactic haloes, and have also been invoked in the Galactic disc as an explanation for the excess faint sub-mm sources detected by SCUBA. Even if their dust-to-gas ratio is only a small percentage of that in conventional gas clouds, these dense systems would be opaque to visible radiation. This presents the possibility of detecting them by looking for occultations of background stars. We examine the possibility that the data sets of microlensing experiments searching for massive compact halo objects can also be used to search for occultation signatures by cold clouds. We compute the rate and timescale distribution of stellar transits by clouds in the Galactic disc and halo. We find that, for cloud parameters typically advocated by theoretical models, thousands of transit events should already exist within microlensing survey data sets. We examine the seasonal modulation in the rate caused by the Earth's orbital motion and find it provides an excellent probe of whether detected clouds are of disc or halo origin.

  19. On the Microphysical Representation of Observed Arctic Mixed-Phase Clouds

    E-Print Network [OSTI]

    Zuidema, Paquita

    On the Microphysical Representation of Observed Arctic Mixed-Phase Clouds Paquita Zuidema, Paul Lawson, Hugh Morrison U of Miami/SPEC, Inc. Boulder CO/NCAR #12;Arctic clouds are often: mixed-phase (ie. both ice + supercooled water) yet long-lasting (despite disequilibrium) #12;why? - are ice nuclei over

  20. Quantifying wet scavenging processes in aircraft observations of nitric acid and cloud condensation nuclei

    E-Print Network [OSTI]

    Palmer, Paul

    Quantifying wet scavenging processes in aircraft observations of nitric acid and cloud condensation indicator for quantifying wet scavenging. Specifically, nitric acid (HNO3), produced as a by-product of combustion, is highly soluble and removed efficiently from clouds by rain. Regional carbon monoxide (CO

  1. The Radiative Properties of Small Clouds: Multi-Scale Observations and Modeling

    SciTech Connect (OSTI)

    Feingold, Graham [NOAA ESRL; McComiskey, Allison [CIRES, University of Colorado

    2013-09-25T23:59:59.000Z

    Warm, liquid clouds and their representation in climate models continue to represent one of the most significant unknowns in climate sensitivity and climate change. Our project combines ARM observations, LES modeling, and satellite imagery to characterize shallow clouds and the role of aerosol in modifying their radiative effects.

  2. Modeling clouds observed at SHEBA using a bulk microphysics parameterization implemented into a single-column model

    E-Print Network [OSTI]

    Shupe, Matthew

    cloud fraction, that is, underpredicting the frequency of liquid- or mixed-phase clouds. The mean ice associated with leads, ``clear-sky'' ice crystal precipitation, and persis- tent mixed-phase clouds. BiasesModeling clouds observed at SHEBA using a bulk microphysics parameterization implemented

  3. Understanding and Improving CRM and GCM Simulations of Cloud Systems with ARM Observations

    SciTech Connect (OSTI)

    Wu, Xiaoqing

    2014-02-25T23:59:59.000Z

    The works supported by this ASR project lay the solid foundation for improving the parameterization of convection and clouds in the NCAR CCSM and the climate simulations. We have made a significant use of CRM simulations and ARM observations to produce thermodynamically and dynamically consistent multi-year cloud and radiative properties; improve the GCM simulations of convection, clouds and radiative heating rate and fluxes using the ARM observations and CRM simulations; and understand the seasonal and annual variation of cloud systems and their impacts on climate mean state and variability. We conducted multi-year simulations over the ARM SGP site using the CRM with multi-year ARM forcing data. The statistics of cloud and radiative properties from the long-term CRM simulations were compared and validated with the ARM measurements and value added products (VAP). We evaluated the multi-year climate simulations produced by the GCM with the modified convection scheme. We used multi-year ARM observations and CRM simulations to validate and further improve the trigger condition and revised closure assumption in NCAR GCM simulations that demonstrate the improvement of climate mean state and variability. We combined the improved convection scheme with the mosaic treatment of subgrid cloud distributions in the radiation scheme of the GCM. The mosaic treatment of cloud distributions has been implemented in the GCM with the original convection scheme and enables the use of more realistic cloud amounts as well as cloud water contents in producing net radiative fluxes closer to observations. A physics-based latent heat (LH) retrieval algorithm was developed by parameterizing the physical linkages of observed hydrometeor profiles of cloud and precipitation to the major processes related to the phase change of atmospheric water.

  4. Cloud, thermodynamic, and precipitation observations in West Africa during 2006

    E-Print Network [OSTI]

    and to evaluate the cloud fields in the National Center for Environmental Prediction Global Forecast System (GFS Atmospheric Divergence using ARM Mobile Facility, GERB data and AMMA Stations (RADAGAST) field campaign, which and precipitation is demonstrated. Cooling of the lower troposphere is implicated as the probable cause

  5. Microphysical Properties of Single and Mixed-Phase Arctic Clouds Derived from AERI Observations

    SciTech Connect (OSTI)

    Turner, David D.

    2003-06-01T23:59:59.000Z

    A novel new approach to retrieve cloud microphysical properties from mixed-phase clouds is presented. This algorithm retrieves cloud optical depth, ice fraction, and the effective size of the water and ice particles from ground-based, high-resolution infrared radiance observations. The theoretical basis is that the absorption coefficient of ice is stronger than that of liquid water from 10-13 mm, whereas liquid water is more absorbing than ice from 16-25 um. However, due to strong absorption in the rotational water vapor absorption band, the 16-25 um spectral region becomes opaque for significant water vapor burdens (i.e., for precipitable water vapor amounts over approximately 1 cm). The Arctic is characterized by its dry and cold atmosphere, as well as a preponderance of mixed-phase clouds, and thus this approach is applicable to Arctic clouds. Since this approach uses infrared observations, cloud properties are retrieved at night and during the long polar wintertime period. The analysis of the cloud properties retrieved during a 7 month period during the Surface Heat Budget of the Arctic (SHEBA) experiment demonstrates many interesting features. These results show a dependence of the optical depth on cloud phase, differences in the mode radius of the water droplets in liquid-only and mid-phase clouds, a lack of temperature dependence in the ice fraction for temperatures above 240 K, seasonal trends in the optical depth with the clouds being thinner in winter and becoming more optically thick in the late spring, and a seasonal trend in the effective size of the water droplets in liquid-only and mixed-phase clouds that is most likely related to aerosol concentration.

  6. Cirrus cloud-temperature interactions over a tropical station, Gadanki from lidar and satellite observations

    SciTech Connect (OSTI)

    S, Motty G, E-mail: mottygs@gmail.com; Satyanarayana, M., E-mail: mottygs@gmail.com; Krishnakumar, V., E-mail: mottygs@gmail.com; Dhaman, Reji k., E-mail: mottygs@gmail.com [Department of Optoelectronics, University of Kerala, Kariavattom, Trivandrum-695 581, Kerala (India)

    2014-10-15T23:59:59.000Z

    The cirrus clouds play an important role in the radiation budget of the earth's atmospheric system and are important to characterize their vertical structure and optical properties. LIDAR measurements are obtained from the tropical station Gadanki (13.5{sup 0} N, 79.2{sup 0} E), India, and meteorological indicators derived from Radiosonde data. Most of the cirrus clouds are observed near to the tropopause, which substantiates the strength of the tropical convective processes. The height and temperature dependencies of cloud height, optical depth, and depolarization ratio were investigated. Cirrus observations made using CALIPSO satellite are compared with lidar data for systematic statistical study of cirrus climatology.

  7. Investigation of the Dynamical, Macrophysical and Radiative Properties of High Clouds Combining Satellite Observations and Climate Model Simulations

    E-Print Network [OSTI]

    Li, Yue

    2012-02-14T23:59:59.000Z

    This dissertation investigates three topics concerning high clouds: 1) convectively coupled equatorial wave (CCEW) signals derived from cloud top temperature (CTT) and cirrus optical thickness retrieved from satellite observations; 2) investigation...

  8. Evaluating Clouds, Aerosols, and their Interactions in Three Global Climate Models using COSP and Satellite Observations

    SciTech Connect (OSTI)

    Ban-Weiss, George; Jin, Ling; Bauer, S.; Bennartz, Ralph; Liu, Xiaohong; Zhang, Kai; Ming, Yi; Guo, Huan; Jiang, Jonathan

    2014-09-23T23:59:59.000Z

    Accurately representing aerosol-cloud interactions in global climate models is challenging. As parameterizations evolve, it is important to evaluate their performance with appropriate use of observations. In this work we compare aerosols, clouds, and their interactions in three climate models (AM3, CAM5, ModelE) to MODIS satellite observations. Modeled cloud properties were diagnosed using the CFMIP Observations Simulator Package (COSP). Cloud droplet number concentrations (N) were derived using the same algorithm for both satellite-simulated model values and observations. We find that aerosol optical depth tau simulated by models is similar to observations. For N, AM3 and CAM5 capture the observed spatial pattern of higher values in near-coast versus remote ocean regions, though modeled values in general are higher than observed. In contrast, ModelE simulates lower N in most near-coast versus remote regions. Aerosol- cloud interactions were computed as the sensitivity of N to tau for marine liquid clouds off the coasts of South Africa and Eastern Asia where aerosol pollution varies in time. AM3 and CAM5 are in most cases more sensitive than observations, while the sensitivity for ModelE is statistically insignificant. This widely used sensitivity could be subject to misinterpretation due to the confounding influence of meteorology on both aerosols and clouds. A simple framework for assessing the N – tau sensitivity at constant meteorology illustrates that observed sensitivity can change from positive to statistically insignificant when including the confounding influence of relative humidity. Satellite simulated values of N were compared to standard model output and found to be higher with a bias of 83 cm-3.

  9. CLOUD LIFE CYCLE OBSERVED DURING THE 2009 CLOUD TOMOGRAPHY FIELD CAMPAIGN

    E-Print Network [OSTI]

    -month experiment, five scanning microwave radiometers were deployed along an eight-kilometer line and programmed cover conditions. The high-resolution tomographic retrievals provide a unique opportunity- 98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript

  10. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    E-Print Network [OSTI]

    Klein, Stephen A.

    2009-01-01T23:59:59.000Z

    cloud has the correct effect on surface fluxes of radiation.radiation is 200 W m –2 in clear-sky STREAMER calculations, the longwave cloud radiative effect

  11. The gravitational redshift of photons traversing a collapsing dust cloud and observable consequences

    E-Print Network [OSTI]

    Néstor Ortiz; Olivier Sarbach

    2014-11-24T23:59:59.000Z

    We analyze the frequency shift of photons propagating on an asymptotically flat spacetime describing a collapsing, spherical dust cloud. We focus on the case where the interaction of the photons with the matter can be neglected. Under fairly general assumptions on the initial data characterizing the collapse, we show that photons with zero angular momentum which travel from past to future null infinity, crossing the collapsing cloud through its center, are always redshifted with respect to stationary observers. We compute this redshift as a function of proper time of a distant stationary observer and discuss its dependency on the mass distribution of the cloud. Possible implications of this redshift effect for weak cosmic censorship and light propagation in cosmological spacetimes are also briefly discussed.

  12. The martian mesosphere as revealed by CO2 cloud observations and General Circulation Modeling

    E-Print Network [OSTI]

    Spiga, Aymeric

    a rare dataset of mesospheric winds. We compare the mesospheric zonal winds pre- dicted by the model by the model. Ã? 2011 Elsevier Inc. All rights reserved. 1. Introduction While the formation of CO2 clouds observations on board Mars Global Surveyor (Clancy et al., 2004, 2007), and later confirmed by THEMIS-VIS (Mc

  13. Observations of the Madden Julian Oscillation for Cloud Modeling Studies

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeeding accessSpeeding access(SC)Gas and OilPhaseObservation ofEdgethe

  14. Westerbork HI observations of high-velocity clouds near M31 and M33

    E-Print Network [OSTI]

    T. Westmeier; R. Braun; D. Thilker

    2005-03-10T23:59:59.000Z

    We have undertaken high-resolution follow-up of a sample of high velocity HI clouds apparently associated with M31. Our sample was chosen from the population of high-velocity clouds (HVCs) detected out to 50 kpc projected radius of the Andromeda Galaxy by Thilker et al. (2004) with the Green Bank Telescope. Nine pointings were observed with the Westerbork Synthesis Radio Telescope to determine the physical parameters of these objects and to find clues to their origin. One additional pointing was directed at a similar object near M33. At 2' resolution we detect 16 individual HVCs around M31 and 1 HVC near M33 with typical HI masses of a few times 10^5 solar masses and sizes of the order of 1 kpc. Estimates of the dynamical and virial masses of some of the HVCs indicate that they are likely gravitationally dominated by additional mass components such as dark matter or ionised gas. Twelve of the clouds are concentrated in an area of only 1 by 1 degree at a projected separation of less than 15 kpc from the disk of M31. This HVC complex has a rather complicated morphological and kinematical structure and partly overlaps with the giant stellar stream of M31, suggesting a tidal origin. Another detected feature is in close proximity, in both position and velocity, with NGC 205, perhaps also indicative of tidal processes. Other HVCs in our survey are isolated and might represent primordial, dark-matter dominated clouds.

  15. Title: Cirrus clouds observation in Santa Maria, Rio Grade do Sul during the experiment Chuva Sul. Authors: Boris Barja(1)

    E-Print Network [OSTI]

    Barbosa, Henrique

    in the research of the atmosphere due their behavior and the effect on the earth radiation budget. They can affect radiation. Also, this cloud type is involved in the dehydration of the upper troposphere and lowerTitle: Cirrus clouds observation in Santa Maria, Rio Grade do Sul during the experiment Chuva ­ Sul

  16. Case study of the 9 April 2009 `brown' cloud: Observations and modeling of convective clouds in Saudi Arabia, David J Delene and Jeffrey S Tilley, University of North Dakota, Grand Forks, ND

    E-Print Network [OSTI]

    Delene, David J.

    Case study of the 9 April 2009 `brown' cloud: Observations and modeling of convective clouds indicated a color change in the accumulated ice. Specifically, the ice color changed from white, during concentrations observed (as well as other changes in the convective cloud properties that were documented

  17. VALIDATION OF CLOUD LIQUID WATER PATH RETRIEVALS FROM SEVIRI ON METEOSAT-8 USING CLOUDNET OBSERVATIONS

    E-Print Network [OSTI]

    Haak, Hein

    on global cloud statistics and radiation budget #12;(Feijt et al., 2003). With the launch of Meteosat Second effective radius and Cloud Liquid Water Path (CLWP) over Europe. The CloudNET research project, supported forecast models. The radiative behavior of clouds depends predominantly on cloud properties

  18. Using MSG-SEVIRI Cloud Physical Properties and Weather Radar Observations for the Detection of Cb/TCu Clouds

    E-Print Network [OSTI]

    Schmeits, Maurice

    . The presence of associated severe weather can be rel- evant to, for example, the transport industry, tourism, the energy supply industry, the construction industry, and farmers. The Cb and TCu clouds may pose a serious Society #12;wind shear, heavy precipitation, and lightning, that is associated with these clouds. Also

  19. Comparison of Simulated and Observed Continental Tropical Anvil Clouds and Their Radiative Heating Profiles

    SciTech Connect (OSTI)

    Powell, Scott W.; Houze, R.; Kumar, Anil; McFarlane, Sally A.

    2012-09-06T23:59:59.000Z

    Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model using six different microphysical schemes. The radar data provide the statistical distribution of the radar reflectivity values as a function of height and anvil thickness. These statistics are compared to the statistics of the modeled anvil cloud reflectivity at all altitudes. Requiring the model to be statistically accurate at all altitudes is a stringent test of the model performance. The typical vertical profile of radiative heating in the anvil clouds is computed from the radar observations. Variability of anvil structures from the different microphysical schemes provides an estimate of the inherent uncertainty in anvil radiative heating profiles. All schemes underestimate the optical thickness of thin anvils and cirrus, resulting in a bias of excessive net anvil heating in all of the simulations.

  20. Global ice cloud observations: radiative properties and statistics from moderate-resolution imaging spectroradiometer measurements

    E-Print Network [OSTI]

    Meyer, Kerry Glynne

    2009-05-15T23:59:59.000Z

    Ice clouds occur quite frequently, yet so much about these clouds is unknown. In recent years, numerous investigations and field campaigns have been focused on the study of ice clouds, all with the ultimate goal of gaining a better understanding...

  1. Observations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget along 20°S

    E-Print Network [OSTI]

    de Szoeke, Simon P.; Yuter, Sandra E.; Mechem, David B.; Fairall, Chris W.; Burleyson, Casey D.; Zuidema, Paquita

    2012-12-01T23:59:59.000Z

    Widespread stratocumulus clouds were observed on nine transects from seven research cruises to the southeastern tropical Pacific Ocean along 20°S, 75°–85°W in October–November of 2001–08. The nine transects sample a unique ...

  2. Patterns of satellite-viewed, subtropical, jet-stream clouds in relation to the observed wind field

    E-Print Network [OSTI]

    Vogt, Richard Joel

    1972-01-01T23:59:59.000Z

    PATTERNS OF SATELLITE-VIEWED, SUBTROPICAL, JET- STREAM CLOUDS IN RELATION TO THE OBSERVED WIND FIELD A Thesis by RICHARD JOEL VOGT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1972 Major Subject: Meteorology PATTERNS OP SATELLITE-VIEWED, SUBTROPICAL, JET-STREAM CLOUDS IN RELATION TO THE OBSERVED WIND FIELD A Thesis by RICHARD JOEL VOGT Approved as to style and content by: (Chairman...

  3. Benchmarking Electron-Cloud Build-Up and Heat-Load Simulations against Large-Hadron-Collider Observations

    E-Print Network [OSTI]

    Dominguez, O; Maury, H; Rumolo, G; Zimmermann, F

    2011-01-01T23:59:59.000Z

    After reviewing the basic features of electron clouds in particle accelerators, the pertinent vacuum-chamber surface properties, and the electron-cloud simulation tools in use at CERN, we report recent observations of electron-cloud phenomena at the Large Hadron Collider (LHC) and ongoing attempts to benchmark the measured LHC vacuum pressure increases and heat loads against electron-cloud build-up simulations aimed at determining the actual surface parameters and at monitoring the so-called scrubbing process. Finally, some other electron-cloud studies related to the LHC are mentioned, and future study plans are described. Presented at MulCoPim2011, Valencia, Spain, 21-23 September 2011.

  4. Interannual Variations of Arctic Cloud Types

    E-Print Network [OSTI]

    Hochberg, Michael

    Sciences #12;Changes in Arctic Climate What is the role of cloud cover in Arctic climate change? What is the Cloud Radiative Effect (CRE) in the Arctic? #12;CRE depends on season, cloud type CRE ­ whether clouds specifically chosen to include nighttime obs Total cloud cover and nine cloud types: - High cloud (cirriform

  5. Interannual Variations of Arctic Cloud Types

    E-Print Network [OSTI]

    Hochberg, Michael

    Declining September sea-ice extent #12;Clouds & Changes in Arctic Climate What is the role of cloud cover in Arctic climate change? What is the Cloud Radiative Effect (CRE) in the Arctic? #12;CRE Defined CRE nighttime obs Total cloud cover and nine cloud types: - High cloud (cirriform) - Middle Clouds: Altocumulus

  6. Evaluation of Mixed-Phase Cloud Microphysics Parameterizations with the NCAR Single Column Climate Model (SCAM) and ARM Observations

    SciTech Connect (OSTI)

    Liu, X; Ghan, SJ; Xie, S

    2007-04-01T23:59:59.000Z

    Mixed-phase stratus clouds are ubiquitous in the Arctic and play an important role in climate in this region. However, climate models have generally proven unsuccessful at simulating the partitioning of condensed water into liquid droplets and ice crystals in these Arctic clouds, which affect modeled cloud phase, cloud lifetime and radiative properties. An ice nucleation parameterization and a vapor deposition scheme were developed that together provide a physically-consistent treatment of mixed-phase clouds in global climate models. These schemes have been implemented in the National Center for Atmospheric Research (NCAR) Community Atmospheric Model Version 3 (CAM3). This report documents the performance of these schemes against ARM Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the CAM single column model version (SCAM). SCAM with our new schemes has a more realistic simulation of the cloud phase structure and the partitioning of condensed water into liquid droplets against observations during the M-PACE than the standard CAM simulations.

  7. Evaluation of Cloud Type Occurrences and Radiative Forcings Simulated by a Cloud Resolving Model Using Observations from Sa...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1, 13Evacuation EmergencyCloudSat, ARM,Cloud Type

  8. Mixed-phase clouds, thin cirrus clouds, and OLR over the tropics: observations, retrievals, and radiative impacts

    E-Print Network [OSTI]

    Lee, Joonsuk

    2009-06-02T23:59:59.000Z

    to the inference of effective particle sizes and optical thicknesses are performed. Errors are calculated with respect to the assumption of a cloud containing solely liquid or ice phase particles. The analyses suggest that the effective particle size inferred for a...

  9. Observational Diagnostics of Self-Gravitating MHD Turbulence in Giant Molecular Clouds

    E-Print Network [OSTI]

    Burkhart, Blakesley; Lazarian, Alex

    2015-01-01T23:59:59.000Z

    We study the observable signatures of self-gravitating MHD turbulence by applying the probability density functions (PDFs) and the spatial density power spectrum to synthetic column density maps. We find that there exists three characterizable stages of the evolution of the collapsing cloud which we term "early," "intermediate," and "advanced." At early times, i.e. $t0.35t_{ff}$, the power spectral slope is positive valued, and a dramatic increase is observed in the PDF moments and the Tsallis incremental PDF parameters, which gives rise to deviations between PDF-sonic Mach number relations. Finally, we show that the imprint of gravity on the density power spectrum can be replicated in non-gravitating turbulence by introducing a delta-function with amplitude equivalent to the maximum valued point in a given self-gravitating map. We find that the turbulence power spectrum restored through spatial filtering of the high density material.

  10. COLLABORATIVE RESEARCH:USING ARM OBSERVATIONS & ADVANCED STATISTICAL TECHNIQUES TO EVALUATE CAM3 CLOUDS FOR DEVELOPMENT OF STOCHASTIC CLOUD-RADIATION

    SciTech Connect (OSTI)

    Somerville, Richard

    2013-08-22T23:59:59.000Z

    The long-range goal of several past and current projects in our DOE-supported research has been the development of new and improved parameterizations of cloud-radiation effects and related processes, using ARM data, and the implementation and testing of these parameterizations in global models. The main objective of the present project being reported on here has been to develop and apply advanced statistical techniques, including Bayesian posterior estimates, to diagnose and evaluate features of both observed and simulated clouds. The research carried out under this project has been novel in two important ways. The first is that it is a key step in the development of practical stochastic cloud-radiation parameterizations, a new category of parameterizations that offers great promise for overcoming many shortcomings of conventional schemes. The second is that this work has brought powerful new tools to bear on the problem, because it has been a collaboration between a meteorologist with long experience in ARM research (Somerville) and a mathematician who is an expert on a class of advanced statistical techniques that are well-suited for diagnosing model cloud simulations using ARM observations (Shen).

  11. 3D Atmospheric Radiative Transfer for Cloud System-Resolving Models: Forward Modelling and Observations

    SciTech Connect (OSTI)

    Howard Barker; Jason Cole

    2012-05-17T23:59:59.000Z

    Utilization of cloud-resolving models and multi-dimensional radiative transfer models to investigate the importance of 3D radiation effects on the numerical simulation of cloud fields and their properties.

  12. Mid-J CO Shock Tracing Observations of Infrared Dark Clouds I

    E-Print Network [OSTI]

    Pon, A; Johnstone, D; Kaufman, M; Butler, M J; Fontani, F; Jiménez-Serra, I; Tan, J C

    2015-01-01T23:59:59.000Z

    Infrared dark clouds (IRDCs) are dense, molecular structures in the interstellar medium that can harbour sites of high-mass star formation. IRDCs contain supersonic turbulence, which is expected to generate shocks that locally heat pockets of gas within the clouds. We present observations of the CO J = 8-7, 9-8, and 10-9 transitions, taken with the Herschel Space Observatory, towards four dense, starless clumps within IRDCs (C1 in G028.37+00.07, F1 and F2 in G034.43+0007, and G2 in G034.77-0.55). We detect the CO J = 8-7 and 9-8 transitions towards three of the clumps (C1, F1, and F2) at intensity levels greater than expected from photodissociation region (PDR) models. The average ratio of the 8-7 to 9-8 lines is also found to be between 1.6 and 2.6 in the three clumps with detections, significantly smaller than expected from PDR models. These low line ratios and large line intensities strongly suggest that the C1, F1, and F2 clumps contain a hot gas component not accounted for by standard PDR models. Such a ...

  13. Aerosol, Cloud, and Climate: From Observation to Model (457th Brookhaven Lecture)

    SciTech Connect (OSTI)

    Wang, Jian (Ph.D., Environmental Sciences Department) [Ph.D., Environmental Sciences Department

    2010-05-12T23:59:59.000Z

    In the last 100 years, the Earth has warmed by about 1ºF, glaciers and sea ice have been melting more quickly than previously, especially during the past decade, and the level of the sea has risen about 6-8 inches worldwide. Scientists have long been investigating this phenomenon of “global warming,” which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions. Among many findings, researchers observed that atmospheric aerosols, minute particles in the atmosphere, can significantly affect global energy balance and climate. Directly, aerosols scatter and absorb sunlight. Indirectly, increased aerosol concentration can lead to smaller cloud droplets, changing clouds in ways that tend to cool global climate and potentially mask overall warming from man-made CO2.

  14. Final Report on the Development of an Improved Cloud Microphysical Product for Model and Remote Sensing Evaluation using RACORO Observations

    SciTech Connect (OSTI)

    McFarquhar, Greg

    2012-09-19T23:59:59.000Z

    We proposed to analyze data collected during the Routine Aerial Facilities (AAF) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) in order to develop an integrated product of cloud microphysical properties (number concentration of drops in different size bins, total liquid drop concentration integrated over all bin sizes, liquid water content LWC, extinction of liquid clouds bw, effective radius of water drops re, and radar reflectivity factor) that could be used to evaluate large-eddy simulations (LES), general circulation models (GCMs) and ground-based remote sensing retrievals, and to develop cloud parameterizations with the end goal of improving the modeling of cloud processes and properties and their impact on atmospheric radiation. We have completed the development of this microphysical database and have submitted it to ARM for consideration of its inclusion on the ARM database as a PI product. This report describes the development of this database, and also describes research that has been conducted on cloud-aerosol interactions using the data obtained during RACORO. A list of conference proceedings and publications is also included.

  15. Evaluation of a New Mixed-Phase Cloud Microphysics Parameterization with CAM3 Single-Column Model and M-PACE Observations

    SciTech Connect (OSTI)

    Liu, Xiaohong; Xie, Shaocheng; Ghan, Steven J.

    2007-12-14T23:59:59.000Z

    Most global climate models generally prescribe the partitioning of condensed water into liquid droplets and ice crystals in mixed-phase clouds according to a temperature-dependent function, which affects modeled cloud phase, cloud lifetime and radiative properties. This study evaluates a new mixed-phase cloud microphysics parameterization (for ice nucleation and water vapor deposition) against the Atmospheric Radiation Measurement (ARM) Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the NCAR Community Atmospheric Model Version 3 (CAM3) single column model (SCAM). It is shown that SCAM with the new scheme produces a more realistic simulation of the cloud phase structure and the partitioning of condensed waterinto liquid droplets against observations during the M-PACE than the standard CAM. Sensitivity test indicates that ice number concentration could play an important role in the simulated mixed-phase cloud microphysics, and thereby needs to be realistically represented in global climate models.

  16. Lidar observations of polar mesospheric clouds at Rothera, Antarctica (67.5S, 68.0W)

    E-Print Network [OSTI]

    Chu, Xinzhao

    Chu,1 Graeme J. Nott,2 Patrick J. Espy,2 Chester S. Gardner,1 Jan C. Diettrich,2 Mark A. Clilverd,2 and Martin J. Jarvis2 Received 15 September 2003; revised 15 October 2003; accepted 30 October 2003. Diettrich, M. A. Clilverd, and M. J. Jarvis (2004), Lidar observations of polar mesospheric clouds

  17. Cloud Services Cloud Services

    E-Print Network [OSTI]

    Cloud Services Cloud Services In 2012 UCD IT Services launched an exciting new set of cloud solutions called CloudEdu, which includes cloud servers, cloud storage, cloud hosting and cloud network. The CloudEdu package includes a consultancy service in design, deployment, management and utilisation

  18. Cloud a particle beam facility to investigate the influence of cosmic rays on clouds

    E-Print Network [OSTI]

    Kirkby, Jasper

    2001-01-01T23:59:59.000Z

    Palaeoclimatic data provide extensive evidence for solar forcing of the climate during the Holocene and the last ice age, but the underlying mechanism remains a mystery. However recent observations suggest that cosmic rays may play a key role. Satellite data have revealed a surprising correlation between cosmic ray intensity and the fraction of the Earth covered by low clouds \\cite{svensmark97,marsh}. Since the cosmic ray intensity is modulated by the solar wind, this may be an important clue to the long-sought mechanism for solar-climate variability. In order to test whether cosmic rays and clouds are causally linked and, if so, to understand the microphysical mechanisms, a novel experiment known as CLOUD\\footnotemark\\ has been proposed \\cite{cloud_proposal}--\\cite{cloud_addendum_2}. CLOUD proposes to investigate ion-aerosol-cloud microphysics under controlled laboratory conditions using a beam from a particle accelerator, which provides a precisely adjustable and measurable artificial source of cosmic rays....

  19. XMM-Newton observation of SNR J0533-7202 in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Kavanagh, P J; Whelan, E T; Maggi, P; Haberl, F; Bozzetto, L M; Filipovic, M D; Crawford, E J

    2015-01-01T23:59:59.000Z

    Aims. We present an X-ray study of the supernova remnant SNR J0533-7202 in the Large Magellanic Cloud (LMC) and determine its physical characteristics based on its X-ray emission. Methods. We observed SNR J0533-7202 with XMM-Newton (flare-filtered exposure times of 18 ks EPIC-pn and 31 ks EPIC-MOS1/MOS2). We produced X-ray images of the SNR, performed an X-ray spectral analysis, and compared the results to multi-wavelength studies. Results. The distribution of X-ray emission is highly non-uniform, with the south-west region brighter than the north-east. The X-ray emission is correlated with the radio emission from the remnant. We determine that this morphology is likely due to the SNR expanding into a non-uniform ambient medium and not an absorption effect. We estimate the size to be 53.9 (\\pm 3.4) x 43.6 (\\pm 3.4) pc, with the major axis rotated ~64 degrees east of north. We find no spectral signatures of ejecta and infer that the X-ray plasma is dominated by swept-up interstellar medium. Using the spectral ...

  20. Evaluation of A New Mixed-Phase Cloud Microphysics Parameterization with the NCAR Climate Atmospheric Model (CAM3) and ARM Observations Fourth Quarter 2007 ARM Metric Report

    SciTech Connect (OSTI)

    X Liu; SJ Ghan; S Xie; J Boyle; SA Klein

    2007-09-30T23:59:59.000Z

    Mixed-phase clouds are composed of a mixture of cloud droplets and ice crystals. The cloud microphysics in mixed-phase clouds can significantly impact cloud optical depth, cloud radiative forcing, and cloud coverage. However, the treatment of mixed-phase clouds in most current climate models is crude and the partitioning of condensed water into liquid droplets and ice crystals is prescribed as temperature dependent functions. In our previous 2007 ARM metric reports a new mixed-phase cloud microphysics parameterization (for ice nucleation and water vapor deposition) was documented and implemented in the NCAR Community Atmospheric Model Version 3 (CAM3). The new scheme was tested against the Atmospheric Radiation Measurement (ARM) Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the single column modeling and short-range weather forecast approaches. In this report this new parameterization is further tested with CAM3 in its climate simulations. It is shown that the predicted ice water content from CAM3 with the new parameterization is in better agreement with the ARM measurements at the Southern Great Plain (SGP) site for the mixed-phase clouds.

  1. Deep Near-Infrared Observations and Identifications of Chandra Sources in the Orion Molecular Cloud 2 and 3

    E-Print Network [OSTI]

    M. Tsujimoto; K. Koyama; N. Kobayashi; M. Goto; Y. Tsuboi; A. T. Tokunaga

    2002-11-24T23:59:59.000Z

    We conducted deep NIR imaging observations of the Orion molecular cloud 2 and 3 using QUIRC on the 88-inch telescope of the University of Hawaii. Our purposes are 1) to generate a comprehensive NIR source catalog of these star forming clouds, and 2) to identify the NIR counterpart of the Chandra X-ray sources that have no counterpart in the 2MASS catalog. Our J-, H-, and K-band observations are about 2 mag deeper than those of 2MASS, and well match the current Chandra observation. We detected 1448 NIR sources, for which we derived the position, the J-, H-, and K-band magnitude, and the 2MASS counterpart. Using this catalog, we identified the NIR counterpart for about 42% of the 2MASS-unIDed Chandra sources. The nature of these Chandra sources are discussed using their NIR colors and spatial distributions, and a dozen protostar and brown dwarf candidates are identified.

  2. Mesoscale model cloud scheme assessment using satellite observations Jean-Pierre Chaboureau, Jean-Pierre Cammas, Patrick J. Mascart, and Jean-Pierre Pinty

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    Mesoscale model cloud scheme assessment using satellite observations Jean-Pierre Chaboureau, Jean of the mesoscale nonhydrostatic (Meso-NH) model has been conducted by comparing synthetic METEOSAT brightness combines the output from a bulk explicit cloud scheme routinely used in mesoscale simulations

  3. Beam Measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) Chamber

    E-Print Network [OSTI]

    Kirkby, Jasper

    2001-01-01T23:59:59.000Z

    A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth's energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Industrial Revolution. However a direct link between cosmic rays and cloud formation has not been unambiguously established. We therefore propose to experimentally measure cloud (water droplet) formation under controlled conditions in a test beam at CERN with a CLOUD chamber, duplicating the conditions prevailing in the troposphere. These data, which have never been previously obtained, will allow a detailed understanding of the possible effects of cosmic rays on clouds and confirm, or otherwise, a direct link between cosmic rays, global cloud cover and the Earth's climate. The measurements will, in turn, allow more reliable calculations to be made of the residual e...

  4. The Kinematics of Molecular Cloud Cores in the Presence of Driven and Decaying Turbulence: Comparisons with Observations

    SciTech Connect (OSTI)

    Offner, S R; Krumholz, M R; Klein, R I; McKee, C F

    2008-04-18T23:59:59.000Z

    In this study we investigate the formation and properties of prestellar and protostellar cores using hydrodynamic, self-gravitating Adaptive Mesh Refinement simulations, comparing the cases where turbulence is continually driven and where it is allowed to decay. We model observations of these cores in the C{sup 18}O(2 {yields} 1), NH{sub 3}(1,1), and N{sub 2}H{sup +} (1 {yields} 0) lines, and from the simulated observations we measure the linewidths of individual cores, the linewidths of the surrounding gas, and the motions of the cores relative to one another. Some of these distributions are significantly different in the driven and decaying runs, making them potential diagnostics for determining whether the turbulence in observed star-forming clouds is driven or decaying. Comparing our simulations with observed cores in the Perseus and {rho} Ophiuchus clouds shows reasonably good agreement between the observed and simulated core-to-core velocity dispersions for both the driven and decaying cases. However, we find that the linewidths through protostellar cores in both simulations are too large compared to the observations. The disagreement is noticeably worse for the decaying simulation, in which cores show highly supersonic infall signatures in their centers that decrease toward their edges, a pattern not seen in the observed regions. This result gives some support to the use of driven turbulence for modeling regions of star formation, but reaching a firm conclusion on the relative merits of driven or decaying turbulence will require more complete data on a larger sample of clouds as well as simulations that include magnetic fields, outflows, and thermal feedback from the protostars.

  5. A13B-0215: Case study of the 9 April 2009 `brown' cloud: Observations of unusually high cloud droplet concentrations in Saudi Arabia, David J Delene, University of North Dakota (delene@aero.und.edu; http://aerosol.atmos.und.edu)

    E-Print Network [OSTI]

    Delene, David J.

    ' cloud: Observations of unusually high cloud droplet concentrations in Saudi Arabia, David J Delene Arabia show a color change, from white during the time of low droplet number concentration, to brown by the cloud is investigated and the changes in cloud properties are documented. Conclusions The 'brown' ice

  6. Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model CAM2 Against Satellite Observations

    E-Print Network [OSTI]

    Bretherton, Chris

    Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model-4738 (Accepted) #12;1 ABSTRACT Cloud climatology and the cloud radiative forcing at the top cloud radiative forcing at the TOA at different latitudes. The differences of cloud vertical structures

  7. Water absorption in Galactic translucent clouds: conditions and history of the gas derived from Herschel/HIFI PRISMAS observations

    E-Print Network [OSTI]

    Flagey, N; Lis, D C; Gerin, M; Neufeld, D; Sonnentrucker, P; De Luca, M; Godard, B; Goicoechea, J R; Monje, R; Phillips, T G

    2012-01-01T23:59:59.000Z

    We present Herschel/HIFI observations of nine transitions of \\hho and \\hheo towards six high-mass star-forming regions, obtained as part of the PRISMAS Key Program. Water vapor in translucent clouds is detected in absorption along every sightline. We derive the column density of \\hho or \\hheo for the lower energy level of each transition observed. The total water column density is about a few $10^{13} \\rm{cm^{-2}}$. We find that the abundance of water relative to hydrogen nuclei is $1\\times10^{-8}$ in agreement with models for oxygen chemistry with high cosmic ray ionization rates. Relative to \\hh, the abundance of water is remarkably constant at $5\\times10^{-8}$. The abundance of water in excited levels is at most 15%, implying that the excitation temperature $T_{ex}$ in the ground state transitions is below 10 K. The column densities derived from the two ortho ground state transitions indicates that $T_{ex}\\simeq5$ K and that the density $n($\\hh$)$ in the clouds is $\\le10^4 \\rm{cm^{-3}}$. For most clouds we...

  8. RACORO LONG-TERM, SYSTEMATIC AIRCRAFT OBSERVATIONS OF BOUNDARY LAYER CLOUDS

    E-Print Network [OSTI]

    ). This type of cloud is common globally, and the Earth's radiative energy balance is particularly sensitive the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid to do so, for United States Government purposes. BNL-91362-2010-CP #12;

  9. The frequency of tropical precipitating clouds as observed by the TRMM PR and ICESat/GLAS

    E-Print Network [OSTI]

    Casey, Sean Patrick

    2009-06-02T23:59:59.000Z

    METHODOLOGY??????????????????? 11 A. Data??????????????????? 11 B. Analysis Method?????????????? 12 III COINCIDENT SCAN ANALYSIS????????????... 18 IV TROPICAL PRECIPITATING CLOUD FRACTION????? 23 V CONCLUSION????????????????????.. 31..., with land-ocean separation included.??????????????. 15 4 a) Horizontal scan and b) cross-section of a sample coincident case from 20 October 2003 over the eastern Democratic Republic of the Congo?????????????????????............. 19 5 Histograms...

  10. Superbubble evolution including the star-forming clouds: Is it possible to reconcile LMC observations with model predictions?

    E-Print Network [OSTI]

    S. Silich; J. Franco

    1999-05-13T23:59:59.000Z

    Here we present a possible solution to the apparent discrepancy between the observed properties of LMC bubbles and the standard, constant density bubble model. A two-dimensional model of a wind-driven bubble expanding from a flattened giant molecular cloud is examined. We conclude that the expansion velocities derived from spherically symmetric models are not always applicable to elongated young bubbles seen almost face-on due to the LMC orientation. In addition, an observational test to differentiate between spherical and elongated bubbles seen face-on is discussed.

  11. The frequency of tropopause-level thick and thin cirrus clouds as observed by CALIPSO and the relationship to relative humidity and outgoing longwave radiation

    E-Print Network [OSTI]

    Cardona, Allison Leanne

    2008-10-10T23:59:59.000Z

    THE FREQUENCY OF TROPOPAUSE-LEVEL THICK AND THIN CIRRUS CLOUDS AS OBSERVED BY CALIPSO AND THE RELATIONSHIP TO RELATIVE HUMIDITY AND OUTGOING LONGWAVE RADIATION A Thesis by ALLISON L. CARDONA Submitted to the Office of Graduate... Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2008 Major Subject: Atmospheric Sciences THE FREQUENCY OF TROPOPAUSE-LEVEL THICK AND THIN CIRRUS CLOUDS AS OBSERVED...

  12. ASCA Observations of the Sgr B2 Cloud: An X-Ray Reflection Nebula

    E-Print Network [OSTI]

    H. Murakami; K. Koyama; M. Sakano; M. Tsujimoto; Y. Maeda

    1999-08-20T23:59:59.000Z

    We present the ASCA results of imaging spectroscopy of the giant molecular cloud Sgr B2. The X-ray spectrum is found to be very peculiar; it exhibits a strong emission line at 6.4 keV, a low energy cutoff below about 4 keV and a pronounced edge-structure at 7.1 keV. The X-ray image is extended and its peak position is shifted from the core of the molecular cloud toward the Galactic center by about 1--2 arcminute. The X-ray spectrum and the morphology are well reproduced by a scenario that X-rays from an external source located in the Galactic center direction are scattered by the molecular cloud Sgr B2, and come into our line of sight. Thus Sgr B2 may be called an X-ray reflection nebula. Possible implications of the Galactic center activity related to this unique source are presented.

  13. Thin Cloud Length Scales Using CALIPSO and CloudSat Data

    E-Print Network [OSTI]

    Solbrig, Jeremy E.

    2010-10-12T23:59:59.000Z

    Thin clouds are the most difficult cloud type to observe. The recent availability of joint cloud products from the active remote sensing instruments aboard CloudSat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) facilitates...

  14. Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Shupe, Matthew

    Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May 2008). These time periods will be expanded in a future submission.

  15. Using Radar, Lidar, and Radiometer measurements to Classify Cloud Type and Study Middle-Level Cloud Properties

    SciTech Connect (OSTI)

    Wang, Zhien

    2010-06-29T23:59:59.000Z

    The project is mainly focused on the characterization of cloud macrophysical and microphysical properties, especially for mixed-phased clouds and middle level ice clouds by combining radar, lidar, and radiometer measurements available from the ACRF sites. First, an advanced mixed-phase cloud retrieval algorithm will be developed to cover all mixed-phase clouds observed at the ACRF NSA site. The algorithm will be applied to the ACRF NSA observations to generate a long-term arctic mixed-phase cloud product for model validations and arctic mixed-phase cloud processes studies. To improve the representation of arctic mixed-phase clouds in GCMs, an advanced understanding of mixed-phase cloud processes is needed. By combining retrieved mixed-phase cloud microphysical properties with in situ data and large-scale meteorological data, the project aim to better understand the generations of ice crystals in supercooled water clouds, the maintenance mechanisms of the arctic mixed-phase clouds, and their connections with large-scale dynamics. The project will try to develop a new retrieval algorithm to study more complex mixed-phase clouds observed at the ACRF SGP site. Compared with optically thin ice clouds, optically thick middle level ice clouds are less studied because of limited available tools. The project will develop a new two wavelength radar technique for optically thick ice cloud study at SGP site by combining the MMCR with the W-band radar measurements. With this new algorithm, the SGP site will have a better capability to study all ice clouds. Another area of the proposal is to generate long-term cloud type classification product for the multiple ACRF sites. The cloud type classification product will not only facilitates the generation of the integrated cloud product by applying different retrieval algorithms to different types of clouds operationally, but will also support other research to better understand cloud properties and to validate model simulations. The ultimate goal is to improve our cloud classification algorithm into a VAP.

  16. THE DEPENDENCE OF BROWN DWARF RADII ON ATMOSPHERIC METALLICITY AND CLOUDS: THEORY AND COMPARISON WITH OBSERVATIONS

    SciTech Connect (OSTI)

    Burrows, Adam; Nampaisarn, Thane [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Heng, Kevin, E-mail: burrows@astro.princeton.edu, E-mail: tnampais@astro.princeton.edu, E-mail: kheng@phys.ethz.ch [Institute for Advanced Study, School of Natural Sciences, 1 Einstein Drive, Princeton, NJ 08540 (United States)

    2011-07-20T23:59:59.000Z

    Employing realistic and consistent atmosphere boundary conditions, we have generated evolutionary models for brown dwarfs and very low mass stars (VLMs) for different atmospheric metallicities ([Fe/H]), with and without clouds. We find that the spread in radius at a given mass and age can be as large as {approx}10% to {approx}25%, with higher-metallicity, higher-cloud-thickness atmospheres resulting quite naturally in larger radii. For each 0.1 dex increase in [Fe/H], radii increase by {approx}1% to {approx}2.5%, depending upon the age and mass. We also find that, while for smaller masses and older ages brown dwarf radii decrease with increasing helium fraction (Y, as expected), for more massive brown dwarfs and a wide range of ages they increase with helium fraction. The increase in radius in going from Y = 0.25 to Y = 0.28 can be as large as {approx}0.025 R{sub J} ({approx}2.5%). Furthermore, we find that for VLMs an increase in atmospheric metallicity from 0.0 to 0.5 dex, increases radii by {approx}4%, and from -0.5 to 0.5 dex by {approx}10%. Therefore, we suggest that opacity due to higher metallicity might naturally account for the apparent radius anomalies in some eclipsing VLM systems. Ten to twenty-five percent variations in radius exceed errors stemming from uncertainties in the equation of state alone. This serves to emphasize that transit and eclipse measurements of brown dwarf radii constrain numerous effects collectively, importantly including the atmosphere and condensate cloud models, and not just the equation of state. At all times, one is testing a multi-parameter theory, and not a universal radius-mass relation.

  17. Evaluation of Cloud-resolving and Limited Area Model Intercomparison Simulations using TWP-ICE Observations. Part 2: Rain Microphysics

    SciTech Connect (OSTI)

    Varble, Adam; Zipser, Edward J.; Fridlind, Ann; Zhu, Ping; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; Shipway, Ben; Williams, Christopher R.

    2014-12-27T23:59:59.000Z

    Ten 3D cloud-resolving model (CRM) simulations and four 3D limited area model (LAM) simulations of an intense mesoscale convective system observed on January 23-24, 2006 during the Tropical Warm Pool – International Cloud Experiment (TWP-ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, co-located UHF and VHF vertical profilers, and a Joss-Waldvogel disdrometer in an attempt to explain published results showing a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One-moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rain water contents (RWCs) that are similar to observed. Two-moment rain schemes with a gamma shape parameter (?) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one-moment schemes, but lower RWCs than observed. Two moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and thus, may have issues balancing raindrop formation, collision coalescence, and raindrop breakup. Assuming a ? of 2.5 rather than 0 for the raindrop size distribution improves one-moment scheme biases, and allowing ? to have values greater than 0 may improve two-moment schemes. Under-predicted stratiform rain rates are associated with under-predicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. In addition to stronger convective updrafts than observed, limited domain size prevents a large, well-developed stratiform region from developing in CRMs, while a dry bias in ECMWF analyses does the same to the LAMs.

  18. Microphysical Effects Determine Macrophysical Response for Aerosol Impacts on Deep Convective Clouds

    SciTech Connect (OSTI)

    Fan, Jiwen; Leung, Lai-Yung R.; Rosenfeld, Daniel; Chen, Qian; Li, Zhanqing; Zhang, Jinqiang; Yan, Hongru

    2013-11-26T23:59:59.000Z

    Deep convective clouds (DCCs) play a crucial role in the general circulation and energy and hydrological cycle of our climate system. Anthropogenic and natural aerosol particles can influence DCCs through changes in cloud properties, precipitation regimes, and radiation balance. Modeling studies have reported both invigoration and suppression of DCCs by aerosols, but none has fully quantified aerosol impacts on convection life cycle and radiative forcing. By conducting multiple month-long cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macro- and micro-physical properties of summer convective clouds in the tropics and mid-latitudes, this study provides the first comprehensive look at how aerosols affect cloud cover, cloud top height (CTH), and radiative forcing. Observations validate these simulation results. We find that microphysical aerosol effects contribute predominantly to increased cloud cover and CTH by inducing larger amount of smaller but longer lasting ice particles in the stratiform/anvils of DCCs with dynamical aerosol effects contributing at most ~ 1/4 of the total increase of cloud cover. The overall effect is a radiative warming in the atmosphere (3 to 5 W m-2) with strong surface cooling (-5 to -8 W m-2). Herein we clearly identified mechanisms more important than and additional to the invigoration effects hypothesized previously that explain the consistent signatures of increased cloud tops area and height by aerosols in DCCs revealed by observations.

  19. Full Stokes observations in the He I 1083 nm spectral region covering an M3.2 flare

    E-Print Network [OSTI]

    Kuckein, C; Sainz, R Manso; Ramos, A Asensio

    2015-01-01T23:59:59.000Z

    We present an exceptional data set acquired with the Vacuum Tower Telescope (Tenerife, Spain) covering the pre-flare, flare, and post-flare stages of an M3.2 flare. The full Stokes spectropolarimetric observations were recorded with the Tenerife Infrared Polarimeter in the He I 1083.0 nm spectral region. The object under study was active region NOAA 11748 on 2013 May 17. During the flare the chomospheric He I 1083.0 nm intensity goes strongly into emission. However, the nearby photospheric Si I 1082.7 nm spectral line profile only gets shallower and stays in absorption. Linear polarization (Stokes Q and U) is detected in all lines of the He I triplet during the flare. Moreover, the circular polarization (Stokes V) is dominant during the flare, being the blue component of the He I triplet much stronger than the red component, and both are stronger than the Si I Stokes V profile. The Si I inversions reveal enormous changes of the photospheric magnetic field during the flare. Before the flare magnetic field conc...

  20. OBSERVATIONS AND PARAMETERIZATION OF BOUNDARY LAYER STRUCTURES AND CLOUDS AT THE ARM TWP NAURU SITE

    E-Print Network [OSTI]

    .S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United-time winds observed at Nauru are very steady from the East during the entire observing period. An excellent of the island) from satellite estimates and the temperature, moisture, and wind observations from the Nauru site

  1. SURFACE CLOUD RADIATIVE FORCING, CLOUD FRACTION AND CLOUD ALBEDO: THEIR RELATIONSHIP AND MULTISCALE VARIATION

    E-Print Network [OSTI]

    that have been used to quantify the effect of clouds on radiation budget in both modeling and observationalSURFACE CLOUD RADIATIVE FORCING, CLOUD FRACTION AND CLOUD ALBEDO: THEIR RELATIONSHIP AND MULTISCALE/Atmospheric Sciences Division Brookhaven National Laboratory P.O. Box, Upton, NY www.bnl.gov ABSTRACT Cloud-radiation

  2. Observational Analysis of Cloud and Precipitation in Midlatitude Cyclones: Northern versus Southern Hemisphere Warm Fronts

    E-Print Network [OSTI]

    Satellite Observations (CALIPSO), and Advanced Microwave Scanning Radiometer for Earth Observing System Extratropical cyclones produce the bulk of the cold- season precipitation in middle and high latitudes and are key contributors to the meridional transport of energy between the equator and the poles. Though

  3. GFDL ARM Project Technical Report: Using ARM Observations to Evaluate Cloud and Convection Parameterizations & Cloud-Convection-Radiation Interactions in the GFDL Atmospheric General Circulation Model

    SciTech Connect (OSTI)

    V. Ramaswamy; L. J. Donner; J-C. Golaz; S. A. Klein

    2010-06-17T23:59:59.000Z

    This report briefly summarizes the progress made by ARM postdoctoral fellow, Yanluan Lin, at GFDL during the period from October 2008 to present. Several ARM datasets have been used for GFDL model evaluation, understanding, and improvement. This includes a new ice fall speed parameterization with riming impact and its test in GFDL AM3, evaluation of model cloud and radiation diurnal and seasonal variation using ARM CMBE data, model ice water content evaluation using ARM cirrus data, and coordination of the TWPICE global model intercomparison. The work illustrates the potential and importance of ARM data for GCM evaluation, understanding, and ultimately, improvement of GCM cloud and radiation parameterizations. Future work includes evaluation and improvement of the new dynamicsPDF cloud scheme and aerosol activation in the GFDL model.

  4. Comparison of cloud types observed from SEVIRI and POLDER2 , F. Parol(2)

    E-Print Network [OSTI]

    Madeleine, Jean-Baptiste

    'Environnement, Commissariat à l'Energie Atomique, 91128 Gif sur Yvette, France. (4) Centre de Météorologie Spatiale Météo of Earth-orbiting instruments designed for Earth's observation, the SEVIRI radiometer onboard Meteosat-8 provides high quality data with 3 km spatial resolution, 15 mn temporal sampling and 12 narrow spectral

  5. Chandra and ASCA Observations of the X-ray-brightest T-Tauri Stars in the Rho Ophiuchi Cloud

    E-Print Network [OSTI]

    Kensuke Imanishi; Masahiro Tsujimoto; Katsuji Koyama

    2002-02-15T23:59:59.000Z

    We present the Chandra ACIS and ASCA GIS results for a series of four long-term observations on DoAr 21, ROXs 21 and ROXs 31; the X-ray brightest T-Tauri stars (TTSs) in the Rho Ophiuchi cloud. In the four observations with a net exposure of ~600 ksec, we found six, three and two flares from DoAr 21, ROXs 21 and ROXs 31, respectively; hence the flare rate is fairly high. The spectra of DoAr 21 are well fitted with a single-temperature plasma model, while those of ROXs 21 and ROXs 31 need an additional soft plasma component. Since DoAr 21 is younger (~10^5 yr) than ROXs 21 and ROXs 31 (~10^6 yr), these results may indicate that the soft component gradually increases as T-Tauri stars age. The abundances are generally sub-solar and vary from element to element. Both high-FIP (first ionization potential) and low-FIP elements show enhancement over the mean abundances. An unusual giant flare is detected from ROXs 31. The peak luminosity and temperature are ~10^33 ergs s^-1 and ~10 keV, respectively. The temperature reaches its peak value before the flux maximum, and is nearly constant (4--5 keV) during the decay phase, indicating successive energy release during the flare. The abundances and absorption show dramatic variability from the quiescent to flare phase.

  6. Investigation of Microphysical Parameterizations of Snow and Ice in Arctic Clouds during M-PACE through ModelObservation Comparisons

    E-Print Network [OSTI]

    Solomon, Amy

    Investigation of Microphysical Parameterizations of Snow and Ice in Arctic Clouds during M the microphysical properties of Arctic mixed-phase stratocumulus. Intensive measurements taken during the Department of Energy Atmospheric Radiation Measurement Program Mixed-Phase Arctic Cloud Experiment (M

  7. Fault Tolerance and Scaling in e-Science Cloud Applications: Observations from the Continuing Development of MODISAzure

    SciTech Connect (OSTI)

    Li, Jie; Humphrey, Marty; Cheah, You-Wei; Ryu, Youngryel; Agarwal, Deb; Jackson, Keith; Ingen, Catharine van

    2010-04-01T23:59:59.000Z

    It can be natural to believe that many of the traditional issues of scale have been eliminated or at least greatly reduced via cloud computing. That is, if one can create a seemingly wellfunctioning cloud application that operates correctly on small or moderate-sized problems, then the very nature of cloud programming abstractions means that the same application will run as well on potentially significantly larger problems. In this paper, we present our experiences taking MODISAzure, our satellite data processing system built on the Windows Azure cloud computing platform, from the proof-of-concept stage to a point of being able to run on significantly larger problem sizes (e.g., from national-scale data sizes to global-scale data sizes). To our knowledge, this is the longest-running eScience application on the nascent Windows Azure platform. We found that while many infrastructure-level issues were thankfully masked from us by the cloud infrastructure, it was valuable to design additional redundancy and fault-tolerance capabilities such as transparent idempotent task retry and logging to support debugging of user code encountering unanticipated data issues. Further, we found that using a commercial cloud means anticipating inconsistent performance and black-box behavior of virtualized compute instances, as well as leveraging changing platform capabilities over time. We believe that the experiences presented in this paper can help future eScience cloud application developers on Windows Azure and other commercial cloud providers.

  8. Real-Time C-Band Radar Observations of 1992 Eruption Clouds from Crater Peak, Mount Spurr Volcano, Alaska

    E-Print Network [OSTI]

    Rose, William I.

    Survey (USGS), and the Federal Aviation Administration (FAA) at Anchorage provides for the exchange of the eruptions has had a considerable impact on commercial aviation in south- central Alaska, particularly of measuring and tracking ash clouds, in order to advise the aviation community about how to avoid ash clouds

  9. THE CLOUDSAT MISSION AND THE A-TRAIN A New Dimension of Space-Based Observations of Clouds and Precipitation

    E-Print Network [OSTI]

    ; ILLINGWORTH AND O'CONNOR--Department of Meteorology, University of Reading, Reading, Berkshire, United Kingdom the wind fields (e.g., Menzel 2001). These large cloud systems are not mere passive tracers of wide. Clouds also dominate the energy budget of the planet. They tend to cool the earth by reflecting sunlight

  10. Observations of tropical clouds from the upgraded MMCR at Darwin and

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeeding accessSpeeding access(SC)Gas and OilPhaseObservation

  11. Urban slum structure: integrating socioeconomic and land cover data to model slum evolution in Salvador, Brazil

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    roofs, white-painted roofs, pavement, and cloud land covers.white-painted roofs, pavement, vegetation, water, sand exposed soil and clouds.

  12. Investigation of Thin Cirrus Cloud Optical and Microphysical Properties on the Basis of Satellite Observations and Fast Radiative Transfer Models

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

    This dissertation focuses on the global investigation of optically thin cirrus cloud optical thickness (tau) and microphysical properties, such as, effective particle size (D_(eff)) and ice crystal habits (shapes), based on the global satellite...

  13. Observed Characteristics of Clouds and Precipitating Systems Associated with the Tropical Circulation in Global Models and Reanalyses

    E-Print Network [OSTI]

    Stachnik, Justin Paul

    2013-03-25T23:59:59.000Z

    This dissertation presents a series of work related to the representation of the Hadley circulation (HC) in atmospheric reanalyses and general circulation models (GCMs), with connections to the underlying tropical and subtropical cloud systems...

  14. Ultraviolet and Optical Observations of OB Associations and Field Stars in the Southwest Region of the Large Magellanic Cloud

    E-Print Network [OSTI]

    Joel Wm. Parker; Dennis Zaritsky; Theodore P. Stecher; Jason Harris; Phil Massey

    2000-12-06T23:59:59.000Z

    Using photometry from the Ultraviolet Imaging Telescope (UIT) and photometry and spectroscopy from three ground-based optical datasets we have analyzed the stellar content of OB associations and field areas in and around the regions N 79, N 81, N 83, and N 94 in the LMC. We compare data for the OB association Lucke-Hodge 2 (LH 2) to determine how strongly the initial mass function (IMF) may depend on different photometric reductions and calibrations. We also correct for the background contribution of field stars, showing the importance of correcting for field star contamination in determinations of the IMF of star formation regions. It is possible that even in the case of an universal IMF, the variability of the density of background stars could be the dominant factor creating the differences between calculated IMFs for OB associations. We have also combined the UIT data with the Magellanic Cloud Photometric Survey to study the distribution of the candidate O-type stars in the field. We find a significant fraction, roughly half, of the candidate O-type stars are found in field regions, far from any obvious OB associations. These stars are greater than 2 arcmin (30 pc) from the boundaries of existing OB associations in the region, which is a distance greater than most O-type stars with typical dispersion velocities will travel in their lifetimes. The origin of these massive field stars (either as runaways, members of low-density star-forming regions, or examples of isolated massive star formation) will have to be determined by further observations and analysis.

  15. Fault Tolerance and Scaling in e-Science Cloud Applications: Observations from the Continuing Development of MODISAzure

    E-Print Network [OSTI]

    Li, Jie

    2011-01-01T23:59:59.000Z

    covers the US continent and uses 15 sinusoidal tiles (Asinusoidal tile is a piece of the globe mosaic which coversfor another 32 sinusoidal tiles. Finally, we calculate the

  16. Analysis of In situ Observations of Cloud Microphysics from M-PACE Final Report, DOE Grant Agreement No. DE-FG02-06ER64168

    SciTech Connect (OSTI)

    Michael R. Poellot

    2009-01-09T23:59:59.000Z

    This report summarizes the findings and accomplishments of work performed under DOE Grant Agreement No. DE-FG02-06ER64168. The focus of the work was the analysis of in situ observations collected by the University of North Dakota Citation research aircraft during the Mixed-Phase Arctic Cloud Experiment (M-PACE). This project was conducted in 2004 along the North Slope of Alaska. The objectives of the research were: to characterize certain microphysical properties of clouds sampled during M-PACE, including spatial variability, precipitation formation, ice multiplication; to examine instrument performance and certain data processing algorithms; and to collaborate with other M-PACE investigators on case study analyses. A summary of the findings of the first two objectives is given here in parts 1 and 2; full results are contained in reports listed in part 3 of this report. The collaborative efforts are described in the publications listed in part 3.

  17. The effect of smoke, dust, and pollution aerosol on shallow cloud development over the Atlantic Ocean

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    radiation by aerosols, however, can reduce the cloud cover. The net aerosol effect on clouds is currently- induced cloud changes, and 1 3 is due to aerosol direct radiative effect. cloud cover cloud height understand the processes. The radiative effect at the top of the atmosphere incurred by the aerosol effect

  18. A High Resolution Hydrometer Phase Classifier Based on Analysis of Cloud Radar Doppler Spectra.

    SciTech Connect (OSTI)

    Luke,E.; Kollias, P.

    2007-08-06T23:59:59.000Z

    The lifecycle and radiative properties of clouds are highly sensitive to the phase of their hydrometeors (i.e., liquid or ice). Knowledge of cloud phase is essential for specifying the optical properties of clouds, or else, large errors can be introduced in the calculation of the cloud radiative fluxes. Current parameterizations of cloud water partition in liquid and ice based on temperature are characterized by large uncertainty (Curry et al., 1996; Hobbs and Rangno, 1998; Intriery et al., 2002). This is particularly important in high geographical latitudes and temperature ranges where both liquid droplets and ice crystal phases can exist (mixed-phase cloud). The mixture of phases has a large effect on cloud radiative properties, and the parameterization of mixed-phase clouds has a large impact on climate simulations (e.g., Gregory and Morris, 1996). Furthermore, the presence of both ice and liquid affects the macroscopic properties of clouds, including their propensity to precipitate. Despite their importance, mixed-phase clouds are severely understudied compared to the arguably simpler single-phase clouds. In-situ measurements in mixed-phase clouds are hindered due to aircraft icing, difficulties distinguishing hydrometeor phase, and discrepancies in methods for deriving physical quantities (Wendisch et al. 1996, Lawson et al. 2001). Satellite-based retrievals of cloud phase in high latitudes are often hindered by the highly reflecting ice-covered ground and persistent temperature inversions. From the ground, the retrieval of mixed-phase cloud properties has been the subject of extensive research over the past 20 years using polarization lidars (e.g., Sassen et al. 1990), dual radar wavelengths (e.g., Gosset and Sauvageot 1992; Sekelsky and McIntosh, 1996), and recently radar Doppler spectra (Shupe et al. 2004). Millimeter-wavelength radars have substantially improved our ability to observe non-precipitating clouds (Kollias et al., 2007) due to their excellent sensitivity that enables the detection of thin cloud layers and their ability to penetrate several non-precipitating cloud layers. However, in mixed-phase clouds conditions, the observed Doppler moments are dominated by the highly reflecting ice crystals and thus can not be used to identify the cloud phase. This limits our ability to identify the spatial distribution of cloud phase and our ability to identify the conditions under which mixed-phase clouds form.

  19. Attribution Analysis of Cloud Feedback 

    E-Print Network [OSTI]

    Zhou, Chen

    2014-07-15T23:59:59.000Z

    Uncertainty on cloud feedback is the primary contributor to the large spread of equilibrium climate sensitivity (ECS) in climate models. In this study, we compare the short-term cloud feedback in climate models with observations, and evaluate...

  20. EVENT CLOUDS : lighter than air architectural structures

    E-Print Network [OSTI]

    Peydro Duclos, Ignacio

    2014-01-01T23:59:59.000Z

    EVENT CLOUD is a versatile covering system that allows events to happen independently to weather conditions. It consists of a lighter than air pneumatic structure, filled either with helium or hot air, that covers spaces ...

  1. Beam Measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) Chamber

    E-Print Network [OSTI]

    Jasper Kirkby

    2001-04-27T23:59:59.000Z

    A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth's energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Industrial Revolution. However a direct link between cosmic rays and cloud formation has not been unambiguously established. We therefore propose to experimentally measure cloud (water droplet) formation under controlled conditions in a test beam at CERN with a CLOUD chamber, duplicating the conditions prevailing in the troposphere. These data, which have never been previously obtained, will allow a detailed understanding of the possible effects of cosmic rays on clouds and confirm, or otherwise, a direct link between cosmic rays, global cloud cover and the Earth's climate. The measurements will, in turn, allow more reliable calculations to be made of the residual effect on global temperatures of the burning of fossil fuels, an issue of profound importance to society. Furthermore, light radio-isotope records indicate a correlation has existed between global climate and the cosmic ray flux extending back over the present inter-glacial and perhaps earlier. This suggests it may eventually become possible to make long-term (10-1,000 year) predictions of changes in the Earth's climate, provided a deeper understanding can be achieved of the ``geomagnetic climate'' of the Sun and Earth that modulates the cosmic-ray flux.

  2. TGRS-2010-00092.R1 1 Abstract--Cloud properties were retrieved by applying the

    E-Print Network [OSTI]

    Dong, Xiquan

    cover (~59%) is divided equally between liquid and ice clouds. Global mean cloud effective heights , respectively, for liquid clouds and 8.3 km, 12.7, 52.2 µm, and 230 gm-2 for ice clouds. Cloud droplet effective radiation processes requires determination of cloud property distributions and the radiation budget

  3. Separating real and apparent effects of cloud, humidity, and dynamics on aerosol optical thickness near cloud edges

    E-Print Network [OSTI]

    Li, Zhanqing

    have reported correlations between AOT and cloud cover, pointing to potential cloud contamination of Energy's Atmospheric Radiation Measurement Program. It was found that aerosol humidification effects can explain about one fourth of the correlation between the cloud cover and AOT. New particle genesis

  4. Evaluation of Cloud-resolving and Limited Area Model Intercomparison Simulations using TWP-ICE Observations. Part 1: Deep Convective Updraft Properties

    SciTech Connect (OSTI)

    Varble, A. C.; Zipser, Edward J.; Fridlind, Ann; Zhu, Ping; Ackerman, Andrew; Chaboureau, Jean-Pierre; Collis, Scott M.; Fan, Jiwen; Hill, Adrian; Shipway, Ben

    2014-12-27T23:59:59.000Z

    Ten 3D cloud-resolving model (CRM) simulations and four 3D limited area model (LAM) simulations of an intense mesoscale convective system observed on January 23-24, 2006 during the Tropical Warm Pool – International Cloud Experiment (TWP-ICE) are compared with each other and with observed radar reflectivity fields and dual-Doppler retrievals of vertical wind speeds in an attempt to explain published results showing a high bias in simulated convective radar reflectivity aloft. This high bias results from ice water content being large, which is a product of large, strong convective updrafts, although hydrometeor size distribution assumptions modulate the size of this bias. Snow reflectivity can exceed 40 dBZ in a two-moment scheme when a constant bulk density of 100 kg m-3 is used. Making snow mass more realistically proportional to area rather than volume should somewhat alleviate this problem. Graupel, unlike snow, produces high biased reflectivity in all simulations. This is associated with large amounts of liquid water above the freezing level in updraft cores. Peak vertical velocities in deep convective updrafts are greater than dual-Doppler retrieved values, especially in the upper troposphere. Freezing of large rainwater contents lofted above the freezing level in simulated updraft cores greatly contributes to these excessive upper tropospheric vertical velocities. Strong simulated updraft cores are nearly undiluted, with some showing supercell characteristics. Decreasing horizontal grid spacing from 900 meters to 100 meters weakens strong updrafts, but not enough to match observational retrievals. Therefore, overly intense simulated updrafts may partly be a product of interactions between convective dynamics, parameterized microphysics, and large-scale environmental biases that promote different convective modes and strengths than observed.

  5. Analysis of Cloud-resolving Simulations of a Tropical Mesoscale Convective System Observed during TWP-ICE: Vertical Fluxes and Draft Properties in Convective and Stratiform Regions

    SciTech Connect (OSTI)

    Mrowiec, Agnieszka A.; Rio, Catherine; Fridlind, Ann; Ackerman, Andrew; Del Genio, Anthony D.; Pauluis, Olivier; Varble, Adam; Fan, Jiwen

    2012-10-02T23:59:59.000Z

    We analyze three cloud-resolving model simulations of a strong convective event observed during the TWP-ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large-scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ~10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ~0.5 independent of species, and the ratio of downdraft to updraft mass flux is ~0.5-0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ~10% (graupel) to ~90% (cloud ice). These findings may lead to improved convection parameterizations.

  6. Investigation of Thin Cirrus Cloud Optical and Microphysical Properties on the Basis of Satellite Observations and Fast Radiative Transfer Models 

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

    observations and fast radiative transfer models (RTMs). In the first part, we develop two computationally efficient RTMs simulating satellite observations under cloudy-sky conditions in the visible/shortwave infrared (VIS/SWIR) and thermal inferred (IR...

  7. Changes in high cloud conditions

    E-Print Network [OSTI]

    Himebrook, Richard Frank

    1974-01-01T23:59:59.000Z

    ). When the effect of unknowns is added to the data (Figs. 3(a) and 3(b), p, 21), the period with most high-cloud cover seems to alter- nate back and forth almost monthly, The average, global, solar radiation (Fig. 3(c), p. 21) depicts a decrease from... radiation, per cent possible sunshine, and average sky cover. The increases in high-cloud cover occurred in areas with the following characteristics: strong upper-air flow; frequent jet ' aircraft traffic; coverage of less than half the sky; late...

  8. LETTER The incidence and implications of clouds for cloud forest plant water relations

    E-Print Network [OSTI]

    Goldsmith, Greg

    , the montane forest experienced higher precipi- tation, cloud cover and leaf wetting events of longer duration for an improved understanding of clouds and their effects on cloud forest plant functioning. As summarised below (VPD) and photosynthetically active radiation. In turn, this decreases plant water demand. The suppres

  9. 7, 1711717146, 2007 Dependence of cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 7, 17117­17146, 2007 Dependence of cloud fraction and cloud height on temperature T. Wagner et a Creative Commons License. Atmospheric Chemistry and Physics Discussions Dependence of cloud fraction and cloud top height on surface temperature derived from spectrally resolved UV/vis satellite observations T

  10. Interannual variations of Arctic cloud types in relation to Ryan Eastman

    E-Print Network [OSTI]

    Hochberg, Michael

    increasing cloud cover, which may promote ice loss by the longwave effect. The trends are positive in all in sea ice extent and thickness may be affected by cloud radiative effect (CRE), and seaice changes may in turn impart changes to cloud cover. Visual cloud reports from land and ocean regions of the Arctic

  11. CLOUD FRACTION: CAN IT BE DEFINED, CAN IT BE MEASURED, AND IF WE KNEW IT

    E-Print Network [OSTI]

    Schwartz, Stephen E.

    droplets and/or ice particles in the atmosphere above the earth's surface. Total cloud cover: Fraction, JGR (ERBE, 1988) Cloud cover is a loosely defined term. Potter Stewart (U.S. Supreme Court, 1964) I feedbacks. Accurate representation of cloud radiative effects is essential in climate models. Getting cloud

  12. Deep Near Infrared Observations of the X-ray Emitting Class 0 Protostar Candidates in the Orion Molecular Cloud-3

    E-Print Network [OSTI]

    M. Tsujimoto; K. Koyama; Y. Tsuboi; G. Chartas; M. Goto; N. Kobayashi; H. Terada; A. T. Tokunaga

    2002-03-09T23:59:59.000Z

    We obtained near infrared (NIR) imaging with the Subaru Telescope of the class 0 protostar candidates in the Orion Molecular Cloud-3, two of which were discovered to have X-ray emission by the Chandra X-ray Observatory. We found strong evidence for the class~0 nature of the X-ray sources. First, our deep K-band image shows no emission brighter than 19.6 mag from both of these X-ray sources. Since class I protostars or class II T Tauri stars should be easily detected in the NIR with this sensitivity, the lack of K-band detection suggests that they are likely much more obscured than class I protostars. Second, our H2 v=1-0 S(1) image shows a bubble-like feature from one of the X-ray class 0 protostar candidates, which reinforces the idea that this is a class 0 protostar. We also discuss the nature of nine NIR sources found in our deep image based on their colors, spatial coincidence with millimeter cores, and the properties of their X-ray counterparts.

  13. Reexamination of the State of the Art Cloud Modeling Shows Real Improvements

    SciTech Connect (OSTI)

    Muehlbauer, Andreas D.; Grabowski, Wojciech W.; Malinowski, S. P.; Ackerman, Thomas P.; Bryan, George; Lebo, Zachary; Milbrandt, Jason; Morrison, H.; Ovchinnikov, Mikhail; Tessendorf, Sarah; Theriault, Julie M.; Thompson, Gregory

    2013-05-25T23:59:59.000Z

    Following up on an almost thirty year long history of International Cloud Modeling Workshops, that started out with a meeting in Irsee, Germany in 1985, the 8th International Cloud Modeling Workshop was held in July 2012 in Warsaw, Poland. The workshop, hosted by the Institute of Geophysics at the University of Warsaw, was organized by Szymon Malinowski and his local team of students and co-chaired by Wojciech Grabowski (NCAR/MMM) and Andreas Muhlbauer (University of Washington). International Cloud Modeling Workshops have been held traditionally every four years typically during the week before the International Conference on Clouds and Precipitation (ICCP) . Rooted in the World Meteorological Organization’s (WMO) weather modification program, the core objectives of the Cloud Modeling Workshop have been centered at the numerical modeling of clouds, cloud microphysics, and the interactions between cloud microphysics and cloud dynamics. In particular, the goal of the workshop is to provide insight into the pertinent problems of today’s state-of-the-art of cloud modeling and to identify key deficiencies in the microphysical representation of clouds in numerical models and cloud parameterizations. In recent years, the workshop has increasingly shifted the focus toward modeling the interactions between aerosols and clouds and provided case studies to investigate both the effects of aerosols on clouds and precipitation as well as the impact of cloud and precipitation processes on aerosols. This time, about 60 (?) scientists from about 10 (?) different countries participated in the workshop and contributed with discussions, oral and poster presentations to the workshop’s plenary and breakout sessions. Several case leaders contributed to the workshop by setting up five observationally-based case studies covering a wide range of cloud types, namely, marine stratocumulus, mid-latitude squall lines, mid-latitude cirrus clouds, Arctic stratus and winter-time orographic clouds and precipitation. Interested readers are encouraged to visit the workshop website at http://www.atmos.washington.edu/~andreasm/workshop2012/ and browse through the list of case studies. The web page also provides a detailed list of participants and the workshop agenda. Aside from contributed oral and poster presentations during the workshop’s plenary sessions, parallel breakout sessions focused on presentations and discussions of the individual cases. A short summary and science highlights from each of the cases is presented below.

  14. Cloud Computing

    SciTech Connect (OSTI)

    Pete Beckman and Ian Foster

    2009-12-04T23:59:59.000Z

    Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

  15. Relationships between Arctic Sea Ice and Clouds during Autumn AXEL J. SCHWEIGER AND RON W. LINDSAY

    E-Print Network [OSTI]

    Francis, Jennifer

    , as the direct radiative effects of cloud cover changes are compensated for by changes in the temperature The connection between sea ice variability and cloud cover over the Arctic seas during autumn is investigated that cloud cover variability near the sea ice margins is strongly linked to sea ice variability. Sea ice

  16. Understanding biases in shortwave cloud radiative forcing in the National Center for Atmospheric Research Community Atmosphere

    E-Print Network [OSTI]

    Zhang, Guang Jun

    in response to El Nin~o warming. The vast cloud cover in the region leads to much stronger cloud greenhouse effect in longwave radiation (longwave cloud radiative forcing) and cloud shielding effect in shortwaveUnderstanding biases in shortwave cloud radiative forcing in the National Center for Atmospheric

  17. Tropical and subtropical cloud transitions in weather and climate prediction models: the GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI)

    SciTech Connect (OSTI)

    Teixeira, J.; Cardoso, S.; Bonazzola, M.; Cole, Jason N.; DelGenio, Anthony D.; DeMott, C.; Franklin, A.; Hannay, Cecile; Jakob, Christian; Jiao, Y.; Karlsson, J.; Kitagawa, H.; Koehler, M.; Kuwano-Yoshida, A.; LeDrian, C.; Lock, Adrian; Miller, M.; Marquet, P.; Martins, J.; Mechoso, C. R.; Meijgaard, E. V.; Meinke, I.; Miranda, P.; Mironov, D.; Neggers, Roel; Pan, H. L.; Randall, David A.; Rasch, Philip J.; Rockel, B.; Rossow, William B.; Ritter, B.; Siebesma, A. P.; Soares, P.; Turk, F. J.; Vaillancourt, P.; Von Engeln, A.; Zhao, M.

    2011-11-01T23:59:59.000Z

    A model evaluation approach is proposed where weather and climate prediction models are analyzed along a Pacific Ocean cross-section, from the stratocumulus regions off the coast of California, across the shallow convection dominated trade-winds, to the deep convection regions of the ITCZ: the GCSS/WGNE Pacific Cross-section Intercomparison (GPCI). The main goal of GPCI is to evaluate, and help understand and improve the representation of tropical and sub-tropical cloud processes in weather and climate prediction models. In this paper, a detailed analysis of cloud regime transitions along the cross-section from the sub-tropics to the tropics for the season JJA of 1998 is presented. This GPCI study confirms many of the typical weather and climate prediction model problems in the representation of clouds: underestimation of clouds in the stratocumulus regime by most models with the corresponding consequences in terms of shortwave radiation biases; overestimation of clouds by the ECMWF Re-Analysis (ERA40) in the deep tropics (in particular) with the corresponding impact in the outgoing longwave radiation; large spread between the different models in terms of cloud cover, liquid water path and shortwave radiation; significant differences between the models in terms of vertical crosssections of cloud properties (in particular), vertical velocity and relative humidity. An alternative analysis of cloud cover mean statistics is proposed where sharp gradients in cloud cover along the GPCI transect are taken into account. This analysis shows that the negative cloud bias of some models and ERA40 in the stratocumulus regions (as compared to ISCCP) is associated not only with lower values of cloud cover in these regimes, but also with a stratocumulus-to-cumulus transition that occurs too early along the trade-wind Lagrangian trajectory. Histograms of cloud cover along the cross-section differ significantly between models. Some models exhibit a quasi-bimodal structure with cloud cover being either very large (close to 100%) or very small, while other models show a more continuous transition. The ISCCP observations suggest that reality is in-between these two extreme examples. These different patterns reflect the diverse nature of the cloud, boundary layer, and convection parameterizations in the participating weather and climate prediction models.

  18. Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing applications

    E-Print Network [OSTI]

    Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing broadening and drizzle growth in shallow liquid clouds remain not well understood. Detailed, cloudscale. Profiling, millimeterwavelength (cloud) radars can provide such observations. In particular, the first three

  19. The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population

    E-Print Network [OSTI]

    Pattle, K; Kirk, J M; White, G J; Drabek-Maunder, E; Buckle, J; Beaulieu, S F; Berry, D S; Broekhoven-Fiene, H; Currie, M J; Fich, M; Hatchell, J; Kirk, H; Jenness, T; Johnstone, D; Mottram, J C; Nutter, D; Pineda, J E; Quinn, C; Salji, C; Tisi, S; Walker-Smith, S; Di Francesco, J; Hogerheijde, M R; André, Ph; Bastien, P; Bresnahan, D; Butner, H; Chen, M; Chrysostomou, A; Coude, S; Davis, C J; Duarte-Cabral, A; Fiege, J; Friberg, P; Friesen, R; Fuller, G A; Graves, S; Greaves, J; Gregson, J; Griffin, M J; Holland, W; Joncas, G; Knee, L B G; Könyves, V; Mairs, S; Marsh, K; Matthews, B C; Moriarty-Schieven, G; Rawlings, J; Richer, J; Robertson, D; Rosolowsky, E; Rumble, D; Sadavoy, S; Spinoglio, L; Thomas, H; Tothill, N; Viti, S; Wouterloot, J; Yates, J; Zhu, M

    2015-01-01T23:59:59.000Z

    In this paper we present the first observations of the Ophiuchus molecular cloud performed as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with the SCUBA-2 instrument. We demonstrate methods for combining these data with previous HARP CO, Herschel, and IRAM N$_{2}$H$^{+}$ observations in order to accurately quantify the properties of the SCUBA-2 sources in Ophiuchus. We produce a catalogue of all of the sources found by SCUBA-2. We separate these into protostars and starless cores. We list all of the starless cores and perform a full virial analysis, including external pressure. This is the first time that external pressure has been included in this level of detail. We find that the majority of our cores are either bound or virialised. Gravitational energy and external pressure are on average of a similar order of magnitude, but with some variation from region to region. We find that cores in the Oph A region are gravitationally bound prestellar cores, while cores in the Oph C and ...

  20. Evaluation of the Daylight Cycle of Model-Predicted Cloud Amount and Condensed Water Path over Europe with Observations from MSG SEVIRI

    E-Print Network [OSTI]

    Stoffelen, Ad

    Evaluation of the Daylight Cycle of Model-Predicted Cloud Amount and Condensed Water Path over accurate information on diurnal cycles during daylight hours of cloud properties over land and ocean surfaces. This paper evaluates the daylight cycle of CA and CWP as predicted by the Regional Atmospheric

  1. The Diurnal Cycle of Clouds and Precipitation along the Sierra Madre Occidental Observed during NAME-2004: Implications for Warm Season Precipitation Estimation

    E-Print Network [OSTI]

    Rutledge, Steven

    . Ground-based precipitation retrievals from the NAME Event Rain Gauge Network (NERN) and Colorado State University­National Center for Atmospheric Research (CSU­NCAR) version 2 radar composites over the southern due to changes in the depth and vigor of shallow clouds and mixed-phase cloud depths

  2. Transmission of Solar Radiation by Clouds over Snow and Ice Surfaces. Part II: Cloud Optical Depth and Shortwave Radiative Forcing from Pyranometer

    E-Print Network [OSTI]

    Warren, Stephen

    coincident hourly sea ice reports, instantaneous cloud radiative forcing and effective cloud optical depth. "Effective" optical depths (for a radiatively equivalent horizontally homogeneous cloud) are classified a characteristic optical depth of 15 at 47°S, increasing to 24 in the region of maximum cloud cover at 58°S

  3. Aerosol Effects on Clouds, Energy & Hydrologic Cycle Steven Ghan, Trond Iversen, Jon Egill Kristjansson, Athanasios Nenes, Joyce Penner

    E-Print Network [OSTI]

    cycle and a "semi-direct" effect by suppressing cloud formation due to absorption of solar radiation cloud coverage. The increased cloud albedo and cloud cover decrease solar insolation at the surfaceAerosol Effects on Clouds, Energy & Hydrologic Cycle Steven Ghan, Trond Iversen, Jon Egill

  4. Observing Conditions and Mid-IR Data Quality Rachel Masona, Andre Wonga, b, Tom Geballea, Kevin Volka, Tom Haywardc, Matt Dillmana,

    E-Print Network [OSTI]

    Harrison, Thomas

    . These data can be used to illustrate the effect of factors such as water vapour column, airmass, cloud cover these effects is important for the efficiency of mid-IR queue observing, the ability of classical observers imaging observations, and which can safely be neglected. Keywords: infrared radiation, infrared

  5. Effective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationship to Aerosol

    E-Print Network [OSTI]

    Schwartz, Stephen E.

    albedo and radiative forcing for a given LWP are highly sensitive to effective radius; for solar zenith and the average cloud cover on earth. Additionally, reduction in cloud cover caused by absorption of solarEffective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationship to Aerosol Byung

  6. Water vapor, cloud liquid water paths, and rain rates over northern high latitude open seas

    E-Print Network [OSTI]

    Zuidema, Paquita

    longwave radiation caused by differences in cloud cover can produce an JOURNAL OF GEOPHYSICAL RESEARCH, VOL-level stratus con- tribute the most to the total Arctic cloud cover of any cloud type according to surface presence during summertime but otherwise the Wentz internal sea-ice screening appears effective

  7. Global Simulations of Ice nucleation and Ice Supersaturation with an Improved Cloud Scheme in the Community Atmosphere Model

    SciTech Connect (OSTI)

    Gettelman, A.; Liu, Xiaohong; Ghan, Steven J.; Morrison, H.; Park, Sungsu; Conley, Andrew; Klein, Stephen A.; Boyle, James; Mitchell, David; Li, J-L F.

    2010-09-28T23:59:59.000Z

    A process-based treatment of ice supersaturation and ice-nucleation is implemented in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). The new scheme is designed to allow (1) supersaturation with respect to ice, (2) ice nucleation by aerosol particles and (3) ice cloud cover consistent with ice microphysics. The scheme is implemented with a 4-class 2 moment microphysics code and is used to evaluate ice cloud nucleation mechanisms and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloud occurrence better than previous versions of the model. Simulations indicate heterogeneous freezing and contact nucleation on dust are both potentially important over remote areas of the Arctic. Cloud forcing and hence climate is sensitive to different formulations of the ice microphysics. Arctic radiative fluxes are sensitive to the parameterization of ice clouds. These results indicate that ice clouds are potentially an important part of understanding cloud forcing and potential cloud feedbacks, particularly in the Arctic.

  8. Polar Cloud Detection using Satellite Data with Analysis and Application of Kernel Learning Algorithms

    E-Print Network [OSTI]

    Shi, Tao

    Abstract Polar Cloud Detection using Satellite Data with Analysis and Application of Kernel Professor Bin Yu, Chair Clouds play a major role in Earth's climate and cloud detection is a crucial step climate model studies. Cloud detection is particularly difficult in the snow- and ice-covered polar

  9. DRAFT, Revised June 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    drops, adding more cloud water, and increasing the cloud cover. Aerosols affect these components1 DRAFT, Revised June 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and opposite effects from shallow and deep clouds Daniel Rosenfeld1 , Robert Wood2 , Leo Donner3 , Steven Sherwood4 1

  10. COVER IMAGE Constraint-satisfaction problems

    E-Print Network [OSTI]

    Loss, Daniel

    : MÁRIA ERCSEY-RAVASZ COVER DESIGN: KAREN MOORE ON THE COVER Trilayer graphene A tale of two stackings Gorman, Ilya Drozdov, Yew San Hor, R. J. Cava and Ali Yazdani 944 Observation of an electrically tunable

  11. Back Cover Front Cover Office of Continuing

    E-Print Network [OSTI]

    Goodman, Robert M.

    Back Cover Front Cover Office of Continuing Professional Education 2012­2013 Professional Landscape of Golf Course Irrigation Systems (p. 13) · Basics of Turf Management (p. 21) · Turfgrass Establishment (p

  12. Effects of biomass-burning-derived aerosols on precipitation and clouds in the Amazon Basin: a satellite-based empirical study

    E-Print Network [OSTI]

    Pielke, Roger A.

    in both 2000 and 2003. With enhanced ta, cloud cover increased significantly, and cloud top temperature convection, leading to higher clouds, enhanced cloud cover, and stronger rainfall. We speculate that changes radiative and hydrological effects on the Amazonian climate system. The accelerated forest burning

  13. Observations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeeding accessSpeeding access(SC)Gas and OilPhaseObservation of aof

  14. Cloud Computing Adam Barker

    E-Print Network [OSTI]

    St Andrews, University of

    Cloud Computing 1 Adam Barker #12;Overview · Introduction to Cloud computing · Enabling technologies · Di erent types of cloud: IaaS, PaaS and SaaS · Cloud terminology · Interacting with a cloud: management consoles · Launching an instance · Connecting to an instance · Running your application · Clouds

  15. Global cloud liquid water path simulations

    SciTech Connect (OSTI)

    Lemus, L. [Southern Hemisphere Meteorology, Clayton, Victoria (Australia)] [Southern Hemisphere Meteorology, Clayton, Victoria (Australia); Rikus, L. [Bureau of Meteorology Research Centre, Melbourne, Victoria (Australia)] [Bureau of Meteorology Research Centre, Melbourne, Victoria (Australia); Martin, C.; Platt, R. [CSIRO, Aspendale, Victoria (Australia)] [CSIRO, Aspendale, Victoria (Australia)

    1997-01-01T23:59:59.000Z

    A new parameterization of cloud liquid water and ice content has been included in the Bureau of Meteorology Global Assimilation and Prediction System. The cloud liquid water content is derived from the mean cloud temperatures in the model using an empirical relationship based on observations. The results from perpetual January and July simulations are presented and show that the total cloud water path steadily decreases toward high latitudes, with two relative maxima at midlatitudes and a peak at low latitudes. To validate the scheme, the simulated fields need to be processed to produce liquid water paths that can be directly compared with the corresponding field derived from Special Sensor Microwave/Imager (SSM/I) data. This requires the identification of cloud ice water content within the parameterization and a prescription to account for the treatment of strongly precipitating subgrid-scale cloud. The resultant cloud liquid water paths agree qualitatively with the SSM/I data but show some systematic errors that are attributed to corresponding errors in the model`s simulation of cloud amounts. Given that a more quantitative validation requires substantial improvement in the model`s diagnostic cloud scheme, the comparison with the SSM/I data indicates that the cloud water path, derived from the cloud liquid water content parameterization introduced in this paper, is consistent with the observations and can be usefully incorporated in the prediction system. 40 refs., 11 figs., 1 tab.

  16. Lecture Ch. 8 Cloud Classification

    E-Print Network [OSTI]

    Russell, Lynn

    clouds Middle clouds Grayish, block the sun, sometimes patchy Sharp outlines, rising, bright white1 Lecture Ch. 8 · Cloud Classification ­ Descriptive approach to clouds · Drop Growth and Precipitation Processes ­ Microphysical characterization of clouds · Complex (i.e. Real) Clouds ­ Examples

  17. Retrieval of Cloud Ice Water Content Profiles from Advanced Microwave Sounding Unit-B Brightness Temperatures Near the Atmospheric Radiation Measurement Southern Great Plains Site

    SciTech Connect (OSTI)

    Seo, E-K.; Liu, G.

    2005-03-18T23:59:59.000Z

    One of the Atmospheric Radiation Measurement (ARM) Program important goals is to develop and test radiation and cloud parameterizations of climate models using single column modeling (SCMs) (Randall et al. 1996). As forcing terms, SCMs need advection tendency of cloud condensates besides the tendencies of temperature, moisture and momentum. To compute the tendency terms of cloud condensates, 3D distribution of cloud condensates over a scale much larger than the climate model's grid scale is needed. Since they can cover a large area within a short time period, satellite measurements are useful utilities to provide advection tendency of cloud condensates for SCMs. However, so far, most satellite retrieval algorithms only retrieve vertically integrated quantities, for example, in the case of cloud ice, ice water path (IWP). To fulfill the requirement of 3D ice water content field for computing ice water advection, in this study, we develop an ice water content profile retrieval algorithm by combining the vertical distribution characteristics obtained from long-term surface radar observations and satellite high-frequency microwave observations that cover a large area. The algorithm is based on the Bayesian theorem using a priori database derived from analyzing cloud radar observations at the Southern Great Plains (SGP) site. The end product of the algorithm is a 3D ice water content covering 10{sup o} x 10{sup o} surrounding the SGP site during the passage of the satellite. This 3D ice water content, together with wind field analysis, can be used to compute the advection tendency of ice water for SCMs.

  18. Cloud Controlling Factors --Low Clouds BJORN STEVENS,

    E-Print Network [OSTI]

    Stevens, Bjorn

    Cloud Controlling Factors -- Low Clouds BJORN STEVENS, Department of Atmospheric and Oceanic) clouds is reviewed, with an emphasis on factors that may be expected to change in a changing climate of low-cloud control- ling processes are offered: these include renewing our focus on theory, model

  19. Cloud Controlling Factors --Low Clouds BJORN STEVENS,

    E-Print Network [OSTI]

    Stevens, Bjorn

    Cloud Controlling Factors -- Low Clouds BJORN STEVENS, Department of Atmospheric and Oceanic conspire to determine the statistics and cli- matology of layers of shallow (boundary layer) clouds of low-cloud control- ling processes are offered: these include renewing our focus on theory, model

  20. Cloud Tracking in Cloud-Resolving Models

    E-Print Network [OSTI]

    Plant, Robert

    Cloud Tracking in Cloud-Resolving Models RMetS Conference 4th September 2007 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations What is the distribution of cloud lifetimes? What factors determine the lifetime of an individual

  1. Cloud Security by Max Garvey

    E-Print Network [OSTI]

    Tolmach, Andrew

    Cloud Security Survey by Max Garvey #12;Cloudy Cloud is Cloudy What is the cloud? On Demand Service Network access Resource pooling Elasticity of Resources Measured Service #12;Cloud Types/Variants Iaa Cloud Public Cloud Hybrid Cloud combination. Private cloud with overflow going to public cloud. #12

  2. Kinematical relations among radar-observed water concentrations, vertical motions, and liquid-water drop-size spectra in convective clouds

    E-Print Network [OSTI]

    Runnels, Robert Clayton

    1962-01-01T23:59:59.000Z

    of return settling are often cloudless or consist of cumulus clouds which have had their growth impeded. If conditions in the atmosphere are favorable, convection cells form and the updraft areas associated with these cells develop into cumulonimbus... and time, M & M(x, y, z, t). The x- and y-directions are horizontal and z-direction is positive toward the zenith. If the quantity M is conservative, the local rate of change at a fixed locality (the local change) can be represented by the following...

  3. Multiple layer insulation cover

    DOE Patents [OSTI]

    Farrell, James J. (Livingston Manor, NY); Donohoe, Anthony J. (Ovid, NY)

    1981-11-03T23:59:59.000Z

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  4. Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report

    SciTech Connect (OSTI)

    Huang, Hsin-Yuan; Hall, Alex

    2013-07-24T23:59:59.000Z

    Stratocumulus and shallow cumulus clouds in subtropical oceanic regions (e.g., Southeast Pacific) cover thousands of square kilometers and play a key role in regulating global climate (e.g., Klein and Hartmann, 1993). Numerical modeling is an essential tool to study these clouds in regional and global systems, but the current generation of climate and weather models has difficulties in representing them in a realistic way (e.g., Siebesma et al., 2004; Stevens et al., 2007; Teixeira et al., 2011). While numerical models resolve the large-scale flow, subgrid-scale parameterizations are needed to estimate small-scale properties (e.g. boundary layer turbulence and convection, clouds, radiation), which have significant influence on the resolved scale due to the complex nonlinear nature of the atmosphere. To represent the contribution of these fine-scale processes to the resolved scale, climate models use various parameterizations, which are the main pieces in the model that contribute to the low clouds dynamics and therefore are the major sources of errors or approximations in their representation. In this project, we aim to 1) improve our understanding of the physical processes in thermal circulation and cloud formation, 2) examine the performance and sensitivity of various parameterizations in the regional weather model (Weather Research and Forecasting model; WRF), and 3) develop, implement, and evaluate the advanced boundary layer parameterization in the regional model to better represent stratocumulus, shallow cumulus, and their transition. Thus, this project includes three major corresponding studies. We find that the mean diurnal cycle is sensitive to model domain in ways that reveal the existence of different contributions originating from the Southeast Pacific land-masses. The experiments suggest that diurnal variations in circulations and thermal structures over this region are influenced by convection over the Peruvian sector of the Andes cordillera, while the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain. According to our experiments, the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer scheme and the WSM6 microphysics scheme is the combination of schemes that performs best. For that combination, mean cloud cover, liquid water path, and cloud depth are fairly wellsimulated, while mean cloud top height remains too low in comparison to observations. Both microphysics and boundary layer schemes contribute to the spread in liquid water path and cloud depth, although the microphysics contribution is slightly more prominent. Boundary layer schemes are the primary contributors to cloud top height, degree of adiabaticity, and cloud cover. Cloud top height is closely related to surface fluxes and boundary layer structure. Thus, our study infers that an appropriate tuning of cloud top height would likely improve the low-cloud representation in the model. Finally, we show that entrainment governs the degree of adiabaticity, while boundary layer decoupling is a control on cloud cover. In the intercomparison study using WRF single-column model experiments, most parameterizations show a poor agreement of the vertical boundary layer structure when compared with large-eddy simulation models. We also implement a new Total-Energy/Mass- Flux boundary layer scheme into the WRF model and evaluate its ability to simulate both stratocumulus and shallow cumulus clouds. Result comparisons against large-eddy simulation show that this advanced parameterization based on the new Eddy-Diffusivity/Mass-Flux approach provides a better performance than other boundary layer parameterizations.

  5. Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes

    E-Print Network [OSTI]

    Niyogi, Dev

    radiation; effect of cloud cover; and effect of high and low aerosol optical depths (AOD). Results indicateDirect observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different, and croplands) with collocated aerosol and surface radiation measurements were analyzed for high and low diffuse

  6. Route leader's name: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADU Observer No(s): . . . . . . . . . . . . . . . . . . . . . . Address: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

    E-Print Network [OSTI]

    de Villiers, Marienne

    choice in each category): Wind: none / light breeze / windy / strong wind. Cloud cover: clear / light cloud / cloudy / overcast. Temperature: cold / cool / moderate / hot / very hot. Rating of count = White Stork;

  7. Cloud Computing og availability

    E-Print Network [OSTI]

    Christensen, Henrik Bærbak

    Cloud Computing og availability Projekt i pålidelighed Henrik Lavdal - 20010210 Søren Bardino Kaa - 20011654 Gruppe 8 19-03-2010 #12;Cloud Computing og availability Side 2 af 28 Indholdsfortegnelse as a Service (SaaS) ...................................................................9 Availability i cloud

  8. Ad hoc cloud computing 

    E-Print Network [OSTI]

    McGilvary, Gary Andrew

    2014-11-27T23:59:59.000Z

    Commercial and private cloud providers offer virtualized resources via a set of co-located and dedicated hosts that are exclusively reserved for the purpose of offering a cloud service. While both cloud models appeal to ...

  9. P2.11 AN ANNUAL CYCLE OF ARCTIC CLOUD MICROPHYSICS Matthew D. Shupe*

    E-Print Network [OSTI]

    Shupe, Matthew

    to classify cloud scenes as all- ice, all-liquid, mixed-phase, or precipitating so that the appropriate ice/snow-covered surfaces. Several studies have demonstrated the importance of specific cloud microphysical properties on cloud-radiation and ice-albedo feedback mechanisms; these in turn have bearing

  10. Aerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic TIMOTHY J. GARRETT1,*

    E-Print Network [OSTI]

    ) studies show that in the Arctic cloud cover generally acts to warm the surface, while coolingAerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic TIMOTHY J. GARRETT1 in the atmosphere tend to increase the reflectance of solar (shortwave) radiation from water clouds, which can lead

  11. A COMPARISON OF SURFACE OBSERVATIONS AND ECHAM4-GCM EXPERIMENTS AND ITS RELEVANCE TO THE INDIRECT AEROSOL EFFECT

    E-Print Network [OSTI]

    of the indirect aerosol effect. The modeled annual cloud cover and solar radiation cycles for the present day at the surface, total cloud cover and precipitation rates have been used to evaluate aerosol. The model correctly predicts the annual mean total cloud cover in Germany and the US, whereas global solar

  12. On Demand Surveillance Service in Vehicular Cloud

    E-Print Network [OSTI]

    Weng, Jui-Ting

    2013-01-01T23:59:59.000Z

    Toward Vehicular Service Cloud . . . . . . . . . . . . . . .4.2 Open Mobile Cloud Requirement . . . . .3.1 Mobile Cloud

  13. Interstellar Turbulence, Cloud Formation and Pressure Balance

    E-Print Network [OSTI]

    Enrique Vazquez-Semadeni

    1998-10-23T23:59:59.000Z

    We discuss HD and MHD compressible turbulence as a cloud-forming and cloud-structuring mechanism in the ISM. Results from a numerical model of the turbulent ISM at large scales suggest that the phase-like appearance of the medium, the typical values of the densities and magnetic field strengths in the intercloud medium, as well as Larson's velocity dispersion-size scaling relation in clouds may be understood as consequences of the interstellar turbulence. However, the density-size relation appears to only hold for the densest simulated clouds, there existing a large population of small, low-density clouds, which, on the other hand, are hardest to observe. We then discuss several tests and implications of a fully dynamical picture of interstellar clouds. The results imply that clouds are transient, constantly being formed, distorted and disrupted by the turbulent velocity field, with a fraction of these fluctuations undergoing gravitational collapse. Simulated line profiles and estimated cloud lifetimes are consistent with observational data. In this scenario, we suggest it is quite unlikely that quasi-hydrostatic structures on any scale can form, and that the near pressure balance between clouds and the intercloud medium is an incidental consequence of the density field driven by the turbulence and in the presence of appropriate cooling, rather than a driving or confining mechanism.

  14. Cirrus cloud simulations using WRF with improved radiation parameterization and increased vertical resolution

    E-Print Network [OSTI]

    Liou, K. N.

    and aerosolcloudradiation interactions. With the newly implemented radiation scheme, the simulations of cloud cover:10.1029/2010JD014574. 1. Introduction [2] Cirrus clouds cover about 20% of the Earth's surface and showed that the effects of radiative processes and vertical transports are both significant in cirrus

  15. ICE AND DUST IN THE PRESTELLAR DARK CLOUD LYNDS 183: PREPLANETARY MATTER AT THE LOWEST TEMPERATURES

    SciTech Connect (OSTI)

    Whittet, D. C. B.; Poteet, C. A.; Bajaj, V. M.; Horne, D. [Department of Physics, Applied Physics and Astronomy and New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Chiar, J. E. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Pagani, L. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, 61 Av. de l'Observatoire, F-75014 Paris (France); Shenoy, S. S. [SOFIA Science Center, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (United States); Adamson, A. J. [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile)

    2013-09-10T23:59:59.000Z

    Dust grains are nucleation centers and catalysts for the growth of icy mantles in quiescent interstellar clouds, the products of which may accumulate into preplanetary matter when new stars and solar systems form within the clouds. In this paper, we present the first spectroscopic detections of silicate dust and the molecular ices H{sub 2}O, CO, and CO{sub 2} in the vicinity of the prestellar core L183 (L134N). An infrared photometric survey of the cloud was used to identify reddened background stars, and we present spectra covering solid-state absorption features in the wavelength range 2-20 {mu}m for nine of them. The mean composition of the ices in the best-studied line of sight (toward J15542044-0254073) is H{sub 2}O:CO:CO{sub 2} Almost-Equal-To 100:40:24. The ices are amorphous in structure, indicating that they have been maintained at low temperature ({approx}< 15 K) since formation. The ice column density N(H{sub 2}O) correlates with reddening by dust, exhibiting a threshold effect that corresponds to the transition from unmantled grains in the outer layers of the cloud to ice-mantled grains within, analogous to that observed in other dark clouds. A comparison of results for L183 and the Taurus and IC 5146 dark clouds suggests common behavior, with mantles first appearing in each case at a dust column corresponding to a peak optical depth {tau}{sub 9.7} = 0.15 {+-} 0.03 in the silicate feature. Our results support a previous conclusion that the color excess E{sub J-K} does not obey a simple linear correlation with the total dust column in lines of sight that intercept dense clouds. The most likely explanation is a systematic change in the optical properties of the dust as the density increases.

  16. Radiation Parameterization for Three-Dimensional Inhomogeneous Cirrus Clouds Applied to ARM Data and Climate Models

    SciTech Connect (OSTI)

    Kuo-Nan Liou

    2003-12-29T23:59:59.000Z

    OAK-B135 (a) We developed a 3D radiative transfer model to simulate the transfer of solar and thermal infrared radiation in inhomogeneous cirrus clouds. The model utilized a diffusion approximation approach (four-term expansion in the intensity) employing Cartesian coordinates. The required single-scattering parameters, including the extinction coefficient, single-scattering albedo, and asymmetry factor, for input to the model, were parameterized in terms of the ice water content and mean effective ice crystal size. The incorporation of gaseous absorption in multiple scattering atmospheres was accomplished by means of the correlated k-distribution approach. In addition, the strong forward diffraction nature in the phase function was accounted for in each predivided spatial grid based on a delta-function adjustment. The radiation parameterization developed herein is applied to potential cloud configurations generated from GCMs to investigate broken clouds and cloud-overlapping effects on the domain-averaged heating rate. Cloud inhomogeneity plays an important role in the determination of flux and heating rate distributions. Clouds with maximum overlap tend to produce less heating than those with random overlap. Broken clouds show more solar heating as well as more IR cooling as compared to a continuous cloud field (Gu and Liou, 2001). (b) We incorporated a contemporary radiation parameterization scheme in the UCLA atmospheric GCM in collaboration with the UCLA GCM group. In conjunction with the cloud/radiation process studies, we developed a physically-based cloud cover formation scheme in association with radiation calculations. The model clouds were first vertically grouped in terms of low, middle, and high types. Maximum overlap was then used for each cloud type, followed by random overlap among the three cloud types. Fu and Liou's 1D radiation code with modification was subsequently employed for pixel-by-pixel radiation calculations in the UCLA GCM. We showed that the simulated cloud cover and OLR fields without special tuning are comparable to those of ISCCP dataset and the results derived from radiation budget experiments. Use of the new radiation and cloud schemes enhances the radiative warming in the middle to upper tropical troposphere and alleviates the cold bias in the UCLA atmospheric GCM. We also illustrated that ice crystal size and cloud inhomogeneous are significant factors affecting the radiation budgets at the top of the atmosphere and the surface (Gu et al. 2003). (c) An innovative approach has been developed to construct a 3D field of inhomogeneous clouds in general and cirrus in particular in terms of liquid/ice water content and particle size on the basis of a unification of satellite and ground-based cloud radar data. Satellite remote sensing employing the current narrow-band spectro-radiometers has limitation and only the vertically integrated cloud parameters (optical depth and mean particle size) can be determined. However, by combining the horizontal cloud mapping inferred from satellites with the vertical structure derived from the profiling Doppler cloud radar, a 3D cloud field can be constructed. This represents a new conceptual approach to 3D remote sensing and imaging and offers a new perspective in observing the cloud structure. We applied this novel technique to AVHRR/NOAA satellite and mm-wave cloud radar data obtained from the ARM achieve and assessed the 3D cirrus cloud field with the ice crystal size distributions independently derived from optical probe measurements aboard the University of North Dakota Citation. The retrieved 3D ice water content and mean effective ice crystal size involving an impressive cirrus cloud occurring on April 18, 1997, are shown to be comparable to those derived from the analysis of collocated and coincident in situ aircraft measurements (Liou et al. 2002). (d) Detection of thin cirrus with optical depths less than 0.5, particularly those occurring i n the tropics remains a fundamental problem in remote sensing. We developed a new detection scheme for the

  17. A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part II: Single-Column Modeling of Arctic Clouds

    E-Print Network [OSTI]

    Shupe, Matthew

    of the arctic bound- ary layer, the presence of leads (cracks) in the sea ice surface, the persistence of mixed-phaseA New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part- dicted cloud boundaries and total cloud fraction compare reasonably well with observations. Cloud phase

  18. Covering Walls With Fabrics.

    E-Print Network [OSTI]

    Anonymous,

    1979-01-01T23:59:59.000Z

    TDOC . Z TA24S.7 8873 NO.1227 WALLS with ;FABRICS Texas Agricultural Extension Service . The Texas A&M University System Daniel C. Pfannstiel, Director, College Station, Texas Covering Walls with Fabrics* When tastefully applied, fabrics... it is applied, fabric-covered walls improve the sound-absorbing acoustical properties of a room. Also, fabrics can be used for covering walls of either textured gypsum board or wood paneling. Home decorating magazines are good sources for ideas about fabric...

  19. Influence of clouds and diffuse radiation on ecosystem-atmosphere CO 2 and CO 18 O exchanges

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    cover, radiation, meteorological and water isotope data tohere, radiation, cloud property, and aerosol data wereData were obtained from the Atmospheric Radiation

  20. Cloud Computing For Bioinformatics

    E-Print Network [OSTI]

    Ferrara, Katherine W.

    Cloud Computing For Bioinformatics EC2 and AMIs #12;Quick-starting an EC2 instance (let's get our feet wet!) Cloud Computing #12;Cloud Computing: EC2 instance Quick Start · On EC2 console, we can click on Launch Instance · This will let us get up and going quickly #12;Cloud Computing: EC2 instance

  1. DO AEROSOLS CHANGE CLOUD COVER AND AFFECT CLIMATE?

    E-Print Network [OSTI]

    Schwartz, Stephen E.

    BALANCE Global and annual average energy fluxes in watts per square meter Schwartz, 1996, modified from;AEROSOL INFLUENCES ON CLIMATE AND CLIMATE CHANGE #12;DMS #12;AEROSOL IN MEXICO CITY BASIN #12;AEROSOL IN MEXICO CITY BASIN Light scattering by aerosols decreases absorption of solar radiation. #12;AEROSOLS

  2. The Experimental Cloud Lidar Pilot Study (ECLIPS) for cloud-radiation research

    SciTech Connect (OSTI)

    Platt, C.M.; Young, S.A. [Division of Atmospheric Research, Victoria (Australia)] [Division of Atmospheric Research, Victoria (Australia); Carswell, A.I.; Pal, S.R. [York Univ., North York, Ontario (Canada)] [York Univ., North York, Ontario (Canada); McCormick, M.P.; Winker, D.M. [NASA Langley Research Center, Hampton, VA (United States)] [NASA Langley Research Center, Hampton, VA (United States); DelGuasta, M.; Stefanutti, L. [Institute Ricerca Onde Elettromagnetiche, Florence (Italy)] [Institute Ricerca Onde Elettromagnetiche, Florence (Italy); Eberhard, W.L.; Hardesty, M. [NOAA Environmental Technology Lab., Boulder, CO (United States)] [and others] [NOAA Environmental Technology Lab., Boulder, CO (United States); and others

    1994-09-01T23:59:59.000Z

    The Experimental Cloud Lidar Pilot Study (ECLIPS) was initiated to obtain statistics on cloud-base height, extinction, optical depth, cloud brokenness, and surface fluxes. Two observational phases have taken place, in October-December 1989 and April-July 1991, with intensive 30-day periods selected within the two time intervals. Data are being archived at NASA Langley Research Center, and, once there, are readily available to the international scientific community. 43 refs., 13 figs., 4 tabs.

  3. Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave radiometer data are systematically compared to models to quantify and

    E-Print Network [OSTI]

    Hogan, Robin

    Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave a systematic evaluation of clouds in forecast models. Clouds and their associated microphysical processes for end users of weather forecasts, who may be interested not only in cloud cover, but in other variables

  4. Tripleclouds: An Efficient Method for Representing Horizontal Cloud Inhomogeneity in 1D Radiation Schemes by Using Three Regions at Each Height

    E-Print Network [OSTI]

    Hogan, Robin

    that a mere 4% increase in global cloud cover could counter- act the warming caused by a doubling of carbon the effect of in- homogeneity on the radiative properties of high cloud. They used cloud radar data to inferTripleclouds: An Efficient Method for Representing Horizontal Cloud Inhomogeneity in 1D Radiation

  5. H I observations of the asymptotic giant branch star X Herculis: Discovery of an extended circumstellar wake superposed on a compact high-velocity cloud

    E-Print Network [OSTI]

    Libert, Y.

    We report H I 21 cm line observations of the asymptotic giant branch (AGB) star X Her obtained with the Robert C. Byrd Green Bank Telescope (GBT) and the Very Large Array. We have unambiguously detected H I emission ...

  6. Chapter 3: Evaluating the impacts of carbonaceous aerosols on clouds and climate

    SciTech Connect (OSTI)

    Menon, Surabi; Del Genio, Anthony D.

    2007-09-03T23:59:59.000Z

    Any attempt to reconcile observed surface temperature changes within the last 150 years to changes simulated by climate models that include various atmospheric forcings is sensitive to the changes attributed to aerosols and aerosol-cloud-climate interactions, which are the main contributors that may well balance the positive forcings associated with greenhouse gases, absorbing aerosols, ozone related changes, etc. These aerosol effects on climate, from various modeling studies discussed in Menon (2004), range from +0.8 to -2.4 W m{sup -2}, with an implied value of -1.0 W m{sup -2} (range from -0.5 to -4.5 W m{sup -2}) for the aerosol indirect effects. Quantifying the contribution of aerosols and aerosol-cloud interactions remain complicated for several reasons some of which are related to aerosol distributions and some to the processes used to represent their effects on clouds. Aerosol effects on low lying marine stratocumulus clouds that cover much of the Earth's surface (about 70%) have been the focus of most of prior aerosol-cloud interaction effect simulations. Since cumulus clouds (shallow and deep convective) are short lived and cover about 15 to 20% of the Earth's surface, they are not usually considered as radiatively important. However, the large amount of latent heat released from convective towers, and corresponding changes in precipitation, especially in biomass regions due to convective heating effects (Graf et al. 2004), suggest that these cloud systems and aerosol effects on them, must be examined more closely. The radiative heating effects for mature deep convective systems can account for 10-30% of maximum latent heating effects and thus cannot be ignored (Jensen and Del Genio 2003). The first study that isolated the sensitivity of cumulus clouds to aerosols was from Nober et al. (2003) who found a reduction in precipitation in biomass burning regions and shifts in circulation patterns. Aerosol effects on convection have been included in other models as well (cf. Jacobson, 2002) but the relative impacts on convective and stratiform processes were not separated. Other changes to atmospheric stability and thermodynamical quantities due to aerosol absorption are also known to be important in modifying cloud macro/micro properties. Linkages between convection and boreal biomass burning can also impact the upper troposphere and lower stratosphere, radiation and cloud microphysical properties via transport of tropospheric aerosols to the lower stratosphere during extreme convection (Fromm and Servranckx 2003). Relevant questions regarding the impact of biomass aerosols on convective cloud properties include the effects of vertical transport of aerosols, spatial and temporal distribution of rainfall, vertical shift in latent heat release, phase shift of precipitation, circulation and their impacts on radiation. Over land surfaces, a decrease in surface shortwave radiation ({approx} 3-6 W m{sup -2} per decade) has been observed between 1960 to 1990, whereas, increases of 0.4 K in land temperature during the same period that occurred have resulted in speculations that evaporation and precipitation should also have decreased (Wild et al. 2004). However, precipitation records for the same period over land do not indicate any significant trend (Beck et al. 2005). The changes in precipitation are thought to be related to increased moisture advection from the oceans (Wild et al. 2004), which may well have some contributions from aerosol-radiation-convection coupling that could modify circulation patterns and hence moisture advection in specific regions. Other important aspects of aerosol effects, besides the direct, semi-direct, microphysical and thermodynamical impacts include alteration of surface albedos, especially snow and ice covered surfaces, due to absorbing aerosols. These effects are uncertain (Jacobson, 2004) but may produce as much as 0.3 W m{sup -2} forcing in the Northern hemisphere that could contribute to melting of ice and permafrost and change in the length of the season (e.g. early arrival of Spring

  7. Retrieval of Cloud Phase Using the Moderate Resolution Imaging Spectroradiometer Data during the Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Spangenberg, D.; Minnis, P.; Shupe, M.; Uttal, T.; Poellot, M.

    2005-03-18T23:59:59.000Z

    Improving climate model predictions over Earth's polar regions requires a comprehensive knowledge of polar cloud microphysics. Over the Arctic, there is minimal contrast between the clouds and background snow surface, making it difficult to detect clouds and retrieve their phase from space. Snow and ice cover, temperature inversions, and the predominance of mixed-phase clouds make it even more difficult to determine cloud phase. Also, since determining cloud phase is the first step toward analyzing cloud optical depth, particle size, and water content, it is vital that the phase be correct in order to obtain accurate microphysical and bulk properties. Changes in these cloud properties will, in turn, affect the Arctic climate since clouds are expected to play a critical role in the sea ice albedo feedback. In this paper, the IR trispectral technique (IRTST) is used as a starting point for a WV and 11-{micro}m brightness temperature (T11) parameterization (WVT11P) of cloud phase using MODIS data. In addition to its ability to detect mixed-phase clouds, the WVT11P also has the capability to identify thin cirrus clouds overlying mixed or liquid phase clouds (multiphase ice). Results from the Atmospheric Radiation Measurement (ARM) MODIS phase model (AMPHM) are compared to the surface-based cloud phase retrievals over the ARM North Slope of Alaska (NSA) Barrow site and to in-situ data taken from University of North Dakota Citation (CIT) aircraft which flew during the Mixed-Phase Arctic Cloud Experiment (MPACE). It will be shown that the IRTST and WVT11P combined to form the AMPHM can achieve a relative high accuracy of phase discrimination compared to the surface-based retrievals. Since it only uses MODIS WV and IR channels, the AMPHM is robust in the sense that it can be applied to daytime, twilight, and nighttime scenes with no discontinuities in the output phase.

  8. Atmospheric Rivers Coming to a Cloud Near You

    ScienceCinema (OSTI)

    Leung, Ruby

    2014-06-12T23:59:59.000Z

    Learn about the ARM Cloud Aerosol Precipitation Experiment (ACAPEX) field campaign in this short video. Ruby Leung, PNNL's lead scientist on this campaign's observational strategy to monitor precipitation.

  9. Atmospheric Rivers Coming to a Cloud Near You

    SciTech Connect (OSTI)

    Leung, Ruby

    2014-03-29T23:59:59.000Z

    Learn about the ARM Cloud Aerosol Precipitation Experiment (ACAPEX) field campaign in this short video. Ruby Leung, PNNL's lead scientist on this campaign's observational strategy to monitor precipitation.

  10. Global simulations of ice nucleation and ice supersaturation with an improved cloud scheme in the Community

    E-Print Network [OSTI]

    Gettelman, Andrew

    and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloud are sensitive to the parameterization of ice clouds. These results indicate that ice clouds are potentiallyGlobal simulations of ice nucleation and ice supersaturation with an improved cloud scheme

  11. Cloud Detection over Snow and Ice Using MISR Data , Eugene E. Clothiaux

    E-Print Network [OSTI]

    Yu, Bin

    Cloud Detection over Snow and Ice Using MISR Data Tao Shi , Bin Yu , Eugene E. Clothiaux , and Amy J. Braverman Abstract Clouds play a major role in Earth's climate and cloud detection prediction and global climate model studies. To advance the observational capabilities of detecting clouds

  12. Remote Sensing: Cloud Properties P Yang, Texas A&M University, College Station, TX, USA

    E-Print Network [OSTI]

    Baum, Bryan A.

    and the effective particle size. Global cloud observations based on satellite measurements serve many uses of supercooled water and ice particles. Water and ice clouds interact with solar radiation differently and have are analyzed routinely for global cloud macrophysical properties such as cloud height, phase (water, ice

  13. CoverSheet

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    overseen by MST-6, that is available for use by qualified users. In FY12 the EML service contract costs were covered by funds from LDRD, BES, NE and other programs. Users...

  14. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    SciTech Connect (OSTI)

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    2012-10-25T23:59:59.000Z

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  15. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  16. Inhomogeneous cloud coverage through the Coulomb explosion of dust in substellar atmospheres

    E-Print Network [OSTI]

    Stark, Craig R; Diver, Declan A

    2015-01-01T23:59:59.000Z

    Recent observations of brown dwarf spectroscopic variability in the infrared infer the presence of patchy cloud cover. This paper proposes a mechanism for producing inhomogeneous cloud coverage due to the depletion of cloud particles through the Coulomb explosion of dust in atmospheric plasma regions. Charged dust grains Coulomb-explode when the electrostatic stress of the grain exceeds its mechanical tensile stress, which results in grains below a critical radius $aclouds in substellar atmospheres, the effect on the dust particle size distribution function, and the resulting radiative properties of the atmospheric regions. Our results show that for an atmospheric plasma region with an electron temperature of $T_{e}=10$~eV ($\\approx10^{5}$~K), the critical grain radius varies from $10^{-7}$ to $10^{-4}$~cm, depending on the grains' tensile strength. Higher critical radii up to $10^{-3}$~cm ...

  17. An Assessment of the Parameterization of Subgrid-Scale Cloud Effects on Radiative Transfer. Part II: Horizontal Inhomogeneity

    E-Print Network [OSTI]

    Stephens, Graeme L.

    in downwelling radiative fluxes at the surface induced by changes in cloud cover and water vapor distributions. 1An Assessment of the Parameterization of Subgrid-Scale Cloud Effects on Radiative Transfer. Part II form 5 January 2005) ABSTRACT The role of horizontal inhomogeneity in radiative transfer through cloud

  18. Use of a Lidar Forward Model for Global Comparisons of Cloud Fraction between the ICESat Lidar and the ECMWF Model

    E-Print Network [OSTI]

    Hogan, Robin

    to underestimate cloud cover in the extra-tropical oceans, the trade wind cumulus, the stratocumulus sheets off-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%. 1. Introduction Clouds play a major role in the Earth's radiation bud- get and predictions of future climate

  19. RISK ASSESSMENT CLOUD COMPUTING

    E-Print Network [OSTI]

    Columbia University

    SECURITY RESEARCH PRIVACY RISK ASSESSMENT AMC DATA FISMA CLOUD COMPUTING MOBILE DEVICES OPERATIONS application hosted in the cloud · Alaska DHHS fined $1.7M ­ Portable device stolen from vehicle · Mass Eye

  20. XSEDE Cloud Survey Report

    E-Print Network [OSTI]

    Walter, M.Todd

    XSEDE Cloud Survey Report David Lifka, Cornell Center for Advanced Computing Ian Foster, ANL, ANL and The University of Chicago A National Science Foundation-sponsored cloud user survey was conducted from September 2012 to April 2013 by the XSEDE Cloud Integration Investigation Team to better

  1. Research Cloud Computing Recommendations

    E-Print Network [OSTI]

    Qian, Ning

    Research Cloud Computing Recommendations SRCPAC December 3, 2014 #12;Mandate and Membership SRCPAC convened this committee in Sept 2014 to investigate the role that cloud computing should play in our & Academic Affairs (Social Work) #12;Questions discussed · What cloud resources are available? · Which kinds

  2. Magnetic Fields in Molecular Cloud Cores

    E-Print Network [OSTI]

    Shantanu Basu

    2004-10-22T23:59:59.000Z

    Observations of magnetic field strengths imply that molecular cloud fragments are individually close to being in a magnetically critical state, even though both magnetic field and column density measurements range over two orders of magnitude. The turbulent pressure also approximately balances the self-gravitational pressure. These results together mean that the one-dimensional velocity dispersion $\\sigv$ is proportional to the mean \\Alf speed of a cloud $\\va$. Global models of MHD turbulence in a molecular cloud show that this correlation is naturally satisfied for a range of different driving strengths of the turbulence. For example, an increase of turbulent driving causes a cloud expansion which also increases $\\va$. Clouds are in a time averaged balance but exhibit large oscillatory motions, particularly in their outer rarefied regions. We also discuss models of gravitational fragmentation in a sheet-like region in which turbulence has already dissipated, including the effects of magnetic fields and ion-neutral friction. Clouds with near-critical mass-to-flux ratios lead to subsonic infall within cores, consistent with some recent observations of motions in starless cores. Conversely, significantly supercritical clouds are expected to produce extended supersonic infall.

  3. Clouds and the Faint Young Sun Paradox

    E-Print Network [OSTI]

    Goldblatt, Colin

    2011-01-01T23:59:59.000Z

    We investigate the role which clouds could play in resolving the Faint Young Sun Paradox (FYSP). Lower solar luminosity in the past means that less energy was absorbed on Earth (a forcing of -50 Wm-2 during the late Archean), but geological evidence points to the Earth being at least as warm as it is today, with only very occasional glaciations. We perform radiative calculations on a single global mean atmospheric column. We select a nominal set of three layered, randomly overlapping clouds, which are both consistent with observed cloud climatologies and reproduce the observed global mean energy budget of Earth. By varying the fraction, thickness, height and particle size of these clouds we conduct a wide exploration of how changed clouds could affect climate, thus constraining how clouds could contribute to resolving the FYSP. Low clouds reflect sunlight but have little greenhouse effect. Removing them entirely gives a~forcing of +25 Wm-2 whilst more modest reduction in their efficacy gives a forcing of +10 ...

  4. Intrinsic Shapes of Molecular Cloud Cores

    E-Print Network [OSTI]

    C. E. Jones; Shantanu Basu; John Dubinski

    2001-01-08T23:59:59.000Z

    We conduct an analysis of the shapes of molecular cloud cores using recently compiled catalogs of observed axis ratios of individual cores mapped in ammonia or through optical selection. We apply both analytical and statistical techniques to deproject the observed axis ratios in order to determine the true distribution of cloud core shapes. We find that neither pure oblate nor pure prolate cores can account for the observed distribution of core shapes. Intrinsically triaxial cores produce distributions which agree with observations. The best-fit triaxial distribution contains cores which are more nearly oblate than prolate.

  5. Uranus at equinox: Cloud morphology and dynamics

    E-Print Network [OSTI]

    Sromovsky, Lawrence; Hammel, Heidi; Ahue, William; de Pater, Imke; Rages, Kathy; Showalter, Mark; van Dam, Marcos

    2015-01-01T23:59:59.000Z

    As the 7 December 2007 equinox of Uranus approached, ring and atmosphere observers produced a substantial collection of observations using the 10-m Keck telescope and the Hubble Space Telescope. Those spanning the period from 7 June 2007 through 9 September 2007 we used to identify and track cloud features, determine atmospheric motions, characterize cloud morphology and dynamics, and define changes in atmospheric band structure. We confirmed the existence of the suspected northern hemisphere prograde jet, locating its peak near 58 N, and extended wind speed measurements to 73 N. For 28 cloud features we obtained extremely high wind-speed accuracy through extended tracking times. The new results confirm a small N-S asymmetry in the zonal wind profile, and the lack of any change in the southern hemisphere between 1986 (near solstice) and 2007 (near equinox) suggests that the asymmetry may be permanent rather than seasonally reversing. In the 2007 images we found two prominent groups of discrete cloud features ...

  6. Covered Product Category: Displays

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including displays, which are covered by the ENERGY STAR program. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  7. Isolating signatures of major cloud-cloud collisions using position-velocity diagrams

    E-Print Network [OSTI]

    Haworth, T J; Fukui, Y; Torii, K; Dale, J E; Shima, K; Takahira, K; Habe, A; Hasegawa, K

    2015-01-01T23:59:59.000Z

    Collisions between giant molecular clouds are a potential mechanism for triggering the formation of massive stars, or even super star clusters. The trouble is identifying this process observationally and distinguishing it from other mechanisms. We produce synthetic position-velocity diagrams from models of: cloud-cloud collisions, non-interacting clouds along the line of sight, clouds with internal radiative feedback and a more complex cloud evolving in a galactic disc, to try and identify unique signatures of collision. We find that a broad bridge feature connecting two intensity peaks, spatially correlated but separated in velocity, is a signature of a high velocity cloud-cloud collision. We show that the broad bridge feature is resilient to the effects of radiative feedback, at least to around 2.5Myr after the formation of the first massive (ionising) star. However for a head on 10km/s collision we find that this will only be observable from 20-30 per cent of viewing angles. Such broad-bridge features have...

  8. Semidirect Dynamical and Radiative Impact of North African Dust Transport on Lower Tropospheric Clouds over the Subtropical North Atlantic in CESM 1.0

    SciTech Connect (OSTI)

    DeFlorio, Mike; Ghan, Steven J.; Singh, Balwinder; Miller, Arthur J.; Cayan, Dan; Russell, Lynn M.; Somerville, Richard C.

    2014-07-16T23:59:59.000Z

    This study uses a century length pre-industrial climate simulation by the Community Earth System Model (CESM 1.0) to explore statistical relationships between dust, clouds and atmospheric circulation, and to suggest a dynamical, rather than microphysical, mechanism linking subtropical North Atlantic lower tropospheric cloud cover with North African dust transport. The length of the run allows us to account for interannual variability of dust emissions and transport downstream of North Africa in the model. CESM’s mean climatology and probability distribution of aerosol optical depth in this region agrees well with available AERONET observations. In addition, CESM shows strong seasonal cycles of dust burden and lower tropospheric cloud fraction, with maximum values occurring during boreal summer, when a strong correlation between these two variables exists downstream of North Africa over the subtropical North Atlantic. Calculations of Estimated Inversion Strength (EIS) and composites of EIS on high and low downstream North Africa dust months during boreal summer reveal that dust is likely increasing inversion strength over this region due to both solar absorption and reflection. We find no evidence for a microphysical link between dust and lower tropospheric clouds in this region. These results yield new insight over an extensive period of time into the complex relationship between North African dust and lower tropospheric clouds over the open ocean, which has previously been hindered by spatiotemporal constraints of observations. Our findings lay a framework for future analyses using sub-monthly data over regions with different underlying dynamics.

  9. Evaluation of tropical cloud and precipitation statistics of CAM3 using CloudSat and CALIPSO data

    SciTech Connect (OSTI)

    Zhang, Y; Klein, S; Boyle, J; Mace, G G

    2008-11-20T23:59:59.000Z

    The combined CloudSat and CALIPSO satellite observations provide the first simultaneous measurements of cloud and precipitation vertical structure, and are used to examine the representation of tropical clouds and precipitation in the Community Atmosphere Model Version 3 (CAM3). A simulator package utilizing a model-to-satellite approach facilitates comparison of model simulations to observations, and a revised clustering method is used to sort the subgrid-scale patterns of clouds and precipitation into principal cloud regimes. Results from weather forecasts performed with CAM3 suggest that the model underestimates the horizontal extent of low and mid-level clouds in subsidence regions, but overestimates that of high clouds in ascending regions. CAM3 strongly overestimates the frequency of occurrence of the deep convection with heavy precipitation regime, but underestimates the horizontal extent of clouds and precipitation at low and middle levels when this regime occurs. This suggests that the model overestimates convective precipitation and underestimates stratiform precipitation consistent with a previous study that used only precipitation observations. Tropical cloud regimes are also evaluated in a different version of the model, CAM3.5, which uses a highly entraining plume in the parameterization of deep convection. While the frequency of occurrence of the deep convection with heavy precipitation regime from CAM3.5 forecasts decreases, the incidence of the low clouds with precipitation and congestus regimes increases. As a result, the parameterization change does not reduce the frequency of precipitating convection that is far too high relative to observations. For both versions of CAM, clouds and precipitation are overly reflective at the frequency of the CloudSat radar and thin clouds that could be detected by the lidar only are underestimated.

  10. Working inside the Cloud: Developing a Cloud Computing Infrastructure

    E-Print Network [OSTI]

    Krause, Rolf

    UROP 2012 Working inside the Cloud: Developing a Cloud Computing Infrastructure Cloud computing and live-migration of running VM. USI participates to the development of the first European Cloud computing for a motivated student that will have a chance to improve his/her knowledge on Cloud computing, Java and/or Ruby

  11. Dynamic Cloud Resource Reservation via Cloud Brokerage

    E-Print Network [OSTI]

    Li, Baochun

    Department of Electrical and Computer Engineering, University of Toronto Department of Electrical@eecg.toronto.edu, liang@utoronto.ca Abstract--Infrastructure-as-a-Service clouds offer diverse pric- ing options

  12. Coverable functions Petr Kucera,

    E-Print Network [OSTI]

    of clauses needed to represent f by a CNF. ess(f) - maximum number of pairwise disjoint essential sets of implicates of f. A function f is coverable, if cnf(f)=ess(f). #12;Talk outline We already know from Horn functions. X E ess(f) = ess(X) + k #12;CNF Graph For a Horn CNF let be the digraph defined as: N

  13. A General Systems Theory for Rain Formation in Warm Clouds

    E-Print Network [OSTI]

    A. M. Selvam

    2014-08-15T23:59:59.000Z

    A cumulus cloud model which can explain the observed characteristics of warm rain formation in monsoon clouds is presented. The model is based on classical statistical physical concepts and satisfies the principle of maximum entropy production. Atmospheric flows exhibit selfsimilar fractal fluctuations that are ubiquitous to all dynamical systems in nature, such as physical, chemical, social, etc and are characterized by inverse power law form for power (eddy energy) spectrum signifying long-range space-time correlations. A general systems theory model for atmospheric flows developed by the author is based on the concept that the large eddy energy is the integrated mean of enclosed turbulent (small scale) eddies. This model gives scale-free universal governing equations for cloud growth processes. The model predicted cloud parameters are in agreement with reported observations, in particular, the cloud dropsize distribution. Rain formation can occur in warm clouds within 30minutes lifetime under favourable conditions of moisture supply in the environment.

  14. An Autonomous Reliabilit Cloud Comput

    E-Print Network [OSTI]

    Buyya, Rajkumar

    An Autonomous Reliabilit Ami Cloud Comput Department of Computing and Informa Abstract--Cloud computing paradigm allo based access to computing and storages s Internet. Since with advances of Cloud. Keywords- Cloud computing; SLA negotiat I. INTRODUCTION Cloud computing has transferred the services

  15. Intercomparison of the Cloud Water Phase among Global Climate Models

    SciTech Connect (OSTI)

    Komurcu, Muge; Storelvmo, Trude; Tan, Ivy; Lohmann, U.; Yun, Yuxing; Penner, Joyce E.; Wang, Yong; Liu, Xiaohong; Takemura, T.

    2014-03-27T23:59:59.000Z

    Mixed-phase clouds (clouds that consist of both cloud droplets and ice crystals) are frequently present in the Earth’s atmosphere and influence the Earth’s energy budget through their radiative properties, which are highly dependent on the cloud water phase. In this study, the phase partitioning of cloud water is compared among six global climate models (GCMs) and with Cloud and Aerosol Lidar with Orthogonal Polarization retrievals. It is found that the GCMs predict vastly different distributions of cloud phase for a given temperature, and none of them are capable of reproducing the spatial distribution or magnitude of the observed phase partitioning. While some GCMs produced liquid water paths comparable to satellite observations, they all failed to preserve sufficient liquid water at mixed-phase cloud temperatures. Our results suggest that validating GCMs using only the vertically integrated water contents could lead to amplified differences in cloud radiative feedback. The sensitivity of the simulated cloud phase in GCMs to the choice of heterogeneous ice nucleation parameterization is also investigated. The response to a change in ice nucleation is quite different for each GCM, and the implementation of the same ice nucleation parameterization in all models does not reduce the spread in simulated phase among GCMs. The results suggest that processes subsequent to ice nucleation are at least as important in determining phase and should be the focus of future studies aimed at understanding and reducing differences among the models.

  16. NOAA Technical Memorandum ERL GLERL-48 LAKE ERIE REGIONAL ICE COVER ANALYSIS: PRELIMINARY RESULTS

    E-Print Network [OSTI]

    NOAA Technical Memorandum ERL GLERL-48 LAKE ERIE REGIONAL ICE COVER ANALYSIS: PRELIMINARY RESULTS R.2 2.3 2.4 2.5 Observation density Average regional ice cover Percentage exceedance from average regional ice cover for discrete ice cover values Contour analysis of percentage ice cover exceedance

  17. Radiative Effects of Dust Aerosols, Natural Cirrus Clouds and Contrails: Broadband Optical Properties and Sensitivity Studies

    E-Print Network [OSTI]

    Yi, Bingqi

    2013-07-09T23:59:59.000Z

    This dissertation aims to study the broadband optical properties and radiative effects of dust aerosols and ice clouds. It covers three main topics: the uncertainty of dust optical properties and radiative effects from the dust particle shape...

  18. Radiative Effects of Dust Aerosols, Natural Cirrus Clouds and Contrails: Broadband Optical Properties and Sensitivity Studies 

    E-Print Network [OSTI]

    Yi, Bingqi

    2013-07-09T23:59:59.000Z

    This dissertation aims to study the broadband optical properties and radiative effects of dust aerosols and ice clouds. It covers three main topics: the uncertainty of dust optical properties and radiative effects from the dust particle shape...

  19. Clouds up close | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    interactions that affect clouds and thus improve climate projections. Contact Heng Xiao Pacific Northwest National Laboratory 902 Battelle Blvd., PO Box 999 MSIN: K9-30...

  20. Finance Idol Word Cloud

    Broader source: Energy.gov [DOE]

    This word cloud represents the topics discussed during the Big and Small Ideas: How to Lower Solar Financing Costs breakout session at the SunShot Grand Challenge.

  1. NERSC Journal Cover Stories

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1AllocationsNOVA Portal:Ott2006.jpg A NewCEN-Cover.png

  2. METR 3223: Physical Meteorology II: Cloud Physics, Atmospheric Electricity and Optics

    E-Print Network [OSTI]

    Droegemeier, Kelvin K.

    METR 3223: Physical Meteorology II: Cloud Physics, Atmospheric Electricity and Optics CLASS: Monday as atmospheric electricity and optics. Specific topics that will be covered are as follows: Cloud physics: Review Lightening Atmospheric optics: Reflection and refraction Optical phenomena GRADES Homework problems: 20% Quiz

  3. A06: Analysis of GRAPE data The effects of anthropogenic aerosols on cloud microphysical properties.

    E-Print Network [OSTI]

    Oxford, University of

    the radiative balance of the atmosphere. This effect is known as the `first direct radiative forcing'[4 of this warming is to reduce the upward movement of moisture and in turn reduce the cloud cover[5]. This `semiA06: Analysis of GRAPE data The effects of anthropogenic aerosols on cloud microphysical properties

  4. Radiative and microphysical properties of Arctic stratus clouds from multiangle downwelling infrared radiances

    E-Print Network [OSTI]

    Shupe, Matthew

    climate is strongly influenced by an extensive and persistent pattern of cloud cover [Francis, 1997 properties can have significant effects on long- wave radiation, which dominates the radiation energy budgetRadiative and microphysical properties of Arctic stratus clouds from multiangle downwelling

  5. GROUND-BASED CLOUD IMAGES AND SKY RADIANCES IN THE VISIBLE AND NEAR INFRARED REGION FROM

    E-Print Network [OSTI]

    Shields, Janet

    the atmospheric heating rates as well as the amount of solar radiation including biologically effective UV preliminary comparisons with model calculations and cloud cover data both from another type of sky imager data are of specific importance to study the role of clouds on the radiation balance of the earth

  6. Inconsistencies between satellite estimates of longwave cloud forcing and dynamical fields from reanalyses

    E-Print Network [OSTI]

    Allan, Richard P.

    of cloud cover. We argue that monthly mean clear-sky outgoing longwave radiation (OLRc) measurements] The greenhouse effect of cloud may be quantified as the difference between outgoing longwave radiation (OLR longwave radiative effect is made which is directly comparable with standard climate model diagnostics

  7. Sandia Energy - Cloud Computing Services

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cloud Computing Services Home Stationary Power Safety, Security & Resilience of Energy Infrastructure Grid Modernization Cyber Security for Electric Infrastructure Cloud Computing...

  8. Profiling clouds' inner life | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    life Released: May 29, 2014 Subgrid modeling pinpoints cloud transformation to uncover true reflective power An accurate understanding of clouds over the ocean is important for...

  9. CONTRIBUTED Green Cloud Computing

    E-Print Network [OSTI]

    Tucker, Rod

    to manage energy consumption across the entire information and communications technology (ICT) sector. While considers both public and private clouds, and includes energy consumption in switching and transmission to energy consumption and cloud computing seems to be an alternative to office-based computing. By Jayant

  10. Toward Securing Sensor Clouds

    E-Print Network [OSTI]

    · 32 GB microSDHC storage 2 Image from http://hothardware.com/News/Leaked-Motorola-DROID-X-2-Daytona Computer Mini Computer External Storage External Storage Router Router Router Router Cloud Computing Cloud: micro surveys, amber alerts 4 #12;Router Router Router Router Mini Computer Mini Computer Mini Computer

  11. Do Gamma-Ray Bursts Come from the Oort Cloud?

    E-Print Network [OSTI]

    T. E. Clarke; O. Blaes; adn S. Tremaine

    1993-10-02T23:59:59.000Z

    We examine the possibility that gamma-ray bursts arise from sources in the Oort comet cloud, basing most of our arguments on accepted models for the formation and spatial distribution of the cloud. We identify three severe problems with such models: (1) There is no known mechanism for producing bursts that can explain the observed burst rate and energetics without violating other observational constraints. (2) The bright source counts cannot be reconciled with standard models for the phase-space distribution of objects in the Oort cloud. (3) The observed isotropy of the available burst data is inconsistent with the expected angular distribution of sources in the Oort cloud. We therefore assert that Oort cloud models of gamma-ray bursts are extremely implausible.

  12. Polytropes: Implications for Molecular Clouds and Dark Matter

    E-Print Network [OSTI]

    Christopher F. McKee

    2000-08-02T23:59:59.000Z

    Polytropic models are reasonably successful in acounting for the observed features of molecular clouds. Multi-pressure polytropes include the various pressure components that are important in molecular clouds, whereas composite polytropes provide a representation for the core halo structure. Small, very dense (n~10^{11} cm^{-3}) molecular clouds have been proposed as models for both dark matter and for extreme scattering events. Insofar as the equation of state in these clouds can be represented by a single polytropic relation (pressure varies as a power of the density), such models conflict with observation. It is possible to contrive composite polytropes that do not conflict with observation, but whether the thermal properties of the clouds are consistent with such structure remains to be determined.

  13. Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud

    E-Print Network [OSTI]

    T. Kudoh; S. Basu

    2003-06-23T23:59:59.000Z

    We perform numerical simulations of nonlinear MHD waves in a gravitationally stratified molecular cloud that is bounded by a hot and tenuous external medium. We study the relation between the strength of the turbulence and various global properties of a molecular cloud, within a 1.5-dimensional approximation. Under the influence of a driving source of Alfvenic disturbances, the cloud is lifted up by the pressure of MHD waves and reaches a steady-state characterized by oscillations about a new time-averaged equilibrium state. The nonlinear effect results in the generation of longitudinal motions and many shock waves; however, the wave kinetic energy remains predominantly in transverse, rather than longitudinal, motions. There is an approximate equipartition of energy between the transverse velocity and fluctuating magnetic field (aspredicted by small-amplitude theory) in the region of the stratified cloud which contains most of the mass; however, this relation breaks down in the outer regions, particularly near the cloud surface, where the motions have a standing-wave character. This means that the Chandrasekhar-Fermi formula applied to molecular clouds must be significantly modified in such regions. Models of an ensemble of clouds show that, for various strengths of the input energy, the velocity dispersion in the cloud $\\sigma \\propto Z^{0.5}$, where $Z$ is a characteristic size of the cloud.Furthermore, $\\sigma$ is always comparable to the mean Alfven velocity of the cloud, consistent with observational results.

  14. Electron cloud effects: codes and simulations at KEK

    E-Print Network [OSTI]

    Ohmi, K

    2013-01-01T23:59:59.000Z

    Electron cloud effects had been studied at KEK-Photon Factory since 1995. e-p instability had been studied in proton rings since 1965 in BINP, ISR and PSR. Study of electron cloud effects with the present style, which was based on numerical simulations, started at 1995 in positron storage rings. The instability observed in KEKPF gave a strong impact to B factories, KEKB and PEPII, which were final stage of their design in those days. History of cure for electron cloud instability overlapped the progress of luminosity performance in KEKB. The studies on electron cloud codes and simulations in KEK are presented.

  15. July 2012July 2012 Cloud Computing and Virtualization:Cloud Computing and Virtualization

    E-Print Network [OSTI]

    Liu, Jiangchuan (JC)

    July 2012July 2012 Cloud Computing and Virtualization:Cloud Computing and Virtualization/26/2633 Recent: CloudRecent: Cloud The fast growth of cloud computing Cloud file storage/synchronization services Google entries about cloud computing: 184,000,000 #12;July 2012July 2012 44/26/2644 Our CloudOur Cloud 7

  16. ON THE STAR FORMATION EFFICIENCY OF TURBULENT MAGNETIZED CLOUDS

    SciTech Connect (OSTI)

    Federrath, Christoph [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800 (Australia)] [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800 (Australia); Klessen, Ralf S., E-mail: christoph.federrath@monash.edu [Institut fuer Theoretische Astrophysik, Zentrum fuer Astronomie, Universitaet Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)

    2013-01-20T23:59:59.000Z

    We study the star formation efficiency (SFE) in simulations and observations of turbulent, magnetized, molecular clouds. We find that the probability density functions (PDFs) of the density and the column density in our simulations with solenoidal, mixed, and compressive forcing of turbulence, sonic Mach numbers of 3-50, and magnetic fields in the super- to the trans-Alfvenic regime all develop power-law tails of flattening slope with increasing SFE. The high-density tails of the PDFs are consistent with equivalent radial density profiles, {rho}{proportional_to}r {sup -{kappa}} with {kappa} {approx} 1.5-2.5, in agreement with observations. Studying velocity-size scalings, we find that all the simulations are consistent with the observed v{proportional_to}l{sup 1/2} scaling of supersonic turbulence and seem to approach Kolmogorov turbulence with v{proportional_to}l{sup 1/3} below the sonic scale. The velocity-size scaling is, however, largely independent of the SFE. In contrast, the density-size and column density-size scalings are highly sensitive to star formation. We find that the power-law slope {alpha} of the density power spectrum, P {sub 3D}({rho}, k){proportional_to}k {sup {alpha}}, or equivalently the {Delta}-variance spectrum of the column density, {sigma}{sup 2} {sub {Delta}}({Sigma}, l) {proportional_to} l{sup -{alpha}}, switches sign from {alpha} {approx}< 0 for SFE {approx} 0 to {alpha} {approx}> 0 when star formation proceeds (SFE > 0). We provide a relation to compute the SFE from a measurement of {alpha}. Studying the literature, we find values ranging from {alpha} = -1.6 to +1.6 in observations covering scales from the large-scale atomic medium, over cold molecular clouds, down to dense star-forming cores. From those {alpha} values, we infer SFEs and find good agreement with independent measurements based on young stellar object (YSO) counts, where available. Our SFE-{alpha} relation provides an independent estimate of the SFE based on the column density map of a cloud alone, without requiring a priori knowledge of star formation activity or YSO counts.

  17. Special study on vegetative covers. [UMTRA Project

    SciTech Connect (OSTI)

    Not Available

    1988-11-01T23:59:59.000Z

    This report describes the findings of a special study on the use of vegetative covers to stabilize tailings piles for the Uranium Mill Tailings Remedial Action (UMTRA) Project. The principal rationale for using plants would be to establish a dynamic system for controlling water balance. Specifically, vegetation would be used to intercept and transpire precipitation to the atmosphere, rather than allowing water to drain into the tailings and mobilize contaminants. This would facilitate compliance with groundwater standards proposed for the UMTRA Project by the Environmental Protection Agency. The goals of the study were to evaluate the feasibility of using vegetative covers on UMTRA Project piles, define the advantages and disadvantages of vegetative covers, and develop general guidelines for their use when such use seems reasonable. The principal method for the study was to analyze and apply to the UMTRA Project the results of research programs on vegetative covers at other US Department of Energy (DOE) waste management facilities. The study also relied upon observations made of existing stabilized piles at UMTRA Project sites where natural vegetation is growing on the rock-covered surfaces. Water balance and erosion models were also used to quantify the long-term performance of vegetative covers planned for the topslopes of stabilized piles at Grand Junction and Durango, Colorado, two UMTRA Project sites where the decision was made during the course of this special study to use vegetative covers. Elements in the design and construction of the vegetative covers at these two sites are discussed in the report, with explanations of the differing features that reflect differing environmental conditions. 28 refs., 18 figs., 9 tabs.

  18. Vegetative covers: Special study. [Final report

    SciTech Connect (OSTI)

    Not Available

    1988-11-01T23:59:59.000Z

    This report describes the findings of a special study on the use of vegetative covers to stabilize tailings piles for the Uranium Mill Tailings Remedial Action (UMTRA) Project. The principal rationale for using plants would be to establish a dynamic system for controlling water balance. Specifically, vegetation would be used to intercept and transpire precipitation to the atmosphere, rather than allowing water to drain into the tailings and mobilize contaminants. This would facilitate compliance with groundwater standards proposed for the UMTRA Project by the Environmental Protection Agency. The goals of the study were to (1) evaluate the feasibility of using vegetative covers on UMTRA Project piles, (2) define the advantages and disadvantages of vegetative covers, and (3) develop general guidelines for their use when such use seems reasonable. The principal method for the study was to analyze and apply to the UMTRA Project the results of research programs on vegetative covers at other US Department of Energy (DOE) waste management facilities. The study also relied upon observations made of existing stabilized piles at UMTRA Project sites (Shiprock, New Mexico; Burrell, Pennsylvania; and Clive, Utah) where natural vegetation is growing on the rock-covered surfaces. Water balance and erosion models were also used to quantify the long-term performance of vegetative covers planned for the topslopes of stabilized piles at Grand Junction and Durango, Colorado, two UMTRA Project sites where the decision was made during the course of this special study to use vegetative covers. Elements in the design and construction of the vegetative covers at these two sites are discussed in the report, with explanations of the differing features that reflect differing environmental conditions.

  19. CoverSheet

    Office of Scientific and Technical Information (OSTI)

    for public release; distribution is unlimited. Title: Optical Observations of Gamma-Ray Bursts: Connections to GeVTeV Jets Author(s): Vestrand, W. Thomas Intended for: TeV...

  20. When Clouds become Green: the Green Open Cloud Architecture

    E-Print Network [OSTI]

    Boyer, Edmond

    of a new original energy-efficient Cloud infrastructure called Green Open Cloud. Keywords. Energy with the support of energy-efficient frameworks dedicated to Cloud architectures. Virtualization is a key feature of the energy-aware Cloud infras- tructure that we propose. The conclusion and future works are reviewed

  1. The GCM Oriented Calipso Cloud Product (CALIPSO-GOCCP) H. Chepfer(1)

    E-Print Network [OSTI]

    Dufresne, Jean-Louis

    ;2 Abstract. This paper presents the GCM-Oriented Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Cloud Product (CALIPSO-GOCCP) designed to evaluate the cloudiness simulated by General the effects of viewing geometry, sensors' sensitivity and vertical overlap of cloud layers. For this purpose

  2. 1 DECEMBER 1995 Validation of Satellite Retrievals of Cloud Microphysics and Liquid Water Path

    E-Print Network [OSTI]

    Han, Quingyuan

    1 DECEMBER 1995 Validation of Satellite Retrievals of Cloud Microphysics and Liquid Water Path Using Observations from FIRE 1, Introduction Q. HAN, * W. Rossow, t R. WELCH, * A. WHITE, * * AND J Cloud effective radii (r) and cloud liquid water path (LWP) are derived from ISCCP spatially sampled

  3. Quantifying uncertainties of cloud microphysical property retrievals with a perturbation method

    E-Print Network [OSTI]

    Ohta, Shigemi

    to their modification effects on global radiation balance and atmospheric water cycle. However, representation of clouds Radiation Measurement (ARM) facility, whose primary goal is to carry out long-term observations of cloudsQuantifying uncertainties of cloud microphysical property retrievals with a perturbation method

  4. Microphysical Properties of Clouds with Low Liquid Water Paths: An Update from Clouds with Low Optical (Water) Depth

    SciTech Connect (OSTI)

    Turner, D.D.; Flynn, C.; Long, C.; McFarlane, S.; Vogelmann, A.; Johnson, K.; Miller, M.; Chiu, C.; Marshak, A.; Wiscombe, W.; Clough, S.A.; Heck, P.; Minnis, P.; Liljegren, J.; Min, Q.; O'Hirok, W.; Wang, Z.

    2005-03-18T23:59:59.000Z

    Clouds play a critical role in the modulation of the radiative transfer in the atmosphere, and how clouds interact with radiation is one of the primary uncertainties in global climate models (GCMs). To reduce this uncertainty, the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program collects an immense amount of data from its Climate Research Facilities (CRFs); these data include observations of radiative fluxes, cloud properties from active and passive remote sensors, upper atmospheric soundings, and other observations. The program's goal is to use these coincident, longterm observations to improve the parameterization of radiative transfer in clear and cloudy atmospheres in GCMs.

  5. Attribution Analysis of Cloud Feedback

    E-Print Network [OSTI]

    Zhou, Chen

    2014-07-15T23:59:59.000Z

    -term global warming. If the EIS-low cloud fraction relationship holds under global warming, it is likely that the tropical low cloud fraction change is non-negative. Climate models without significant negative low cloud fraction change suggest that the cloud...

  6. Convective Cloud Lifecycles Lunchtime seminar

    E-Print Network [OSTI]

    Plant, Robert

    Convective Cloud Lifecycles Lunchtime seminar 19th May 2009 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations Why Conclusions Convective Cloud Lifecycles ­ p.1/3 #12;Why bother? Convective Cloud Lifecycles ­ p.2/3 #12;Some

  7. Identifying clouds over the Pierre Auger Observatory using infrared satellite data

    SciTech Connect (OSTI)

    Abreu, Pedro; et al.,

    2013-12-01T23:59:59.000Z

    We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km^2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ~2.4 km by ~5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

  8. Properties of High-Redshift Lyman Alpha Clouds II. Statistical Properties of the Clouds

    E-Print Network [OSTI]

    William H. Press; George B. Rybicki

    1993-03-29T23:59:59.000Z

    Curve of growth analysis, applied to the Lyman series absorption ratios deduced in our previous paper, yields a measurement of the logarithmic slope of distribution of \\Lya\\ clouds in column density $N$. The observed exponential distribution of the clouds' equivalent widths $W$ is then shown to require a broad distribution of velocity parameters $b$, extending up to 80 km s$^{-1}$. We show how the exponential itself emerges in a natural way. An absolute normalization for the differential distribution of cloud numbers in $z$, $N$, and $b$ is obtained. By detailed analysis of absorption fluctuations along the line of sight we are able to put upper limits on the cloud-cloud correlation function $\\xi$ on several megaparsec length scales. We show that observed $b$ values, if thermal, are incompatible, in several different ways, with the hypothesis of equilibrium heating and ionization by a background UV flux. Either a significant component of $b$ is due to bulk motion (which we argue against on several grounds), or else the clouds are out of equilibrium, and hotter than is implied by their ionization state, a situation which could be indicative of recent adiabatic collapse.

  9. Cloud Properties and Radiative Heating Rates for TWP

    SciTech Connect (OSTI)

    Comstock, Jennifer

    2013-11-07T23:59:59.000Z

    A cloud properties and radiative heating rates dataset is presented where cloud properties retrieved using lidar and radar observations are input into a radiative transfer model to compute radiative fluxes and heating rates at three ARM sites located in the Tropical Western Pacific (TWP) region. The cloud properties retrieval is a conditional retrieval that applies various retrieval techniques depending on the available data, that is if lidar, radar or both instruments detect cloud. This Combined Remote Sensor Retrieval Algorithm (CombRet) produces vertical profiles of liquid or ice water content (LWC or IWC), droplet effective radius (re), ice crystal generalized effective size (Dge), cloud phase, and cloud boundaries. The algorithm was compared with 3 other independent algorithms to help estimate the uncertainty in the cloud properties, fluxes, and heating rates (Comstock et al. 2013). The dataset is provided at 2 min temporal and 90 m vertical resolution. The current dataset is applied to time periods when the MMCR (Millimeter Cloud Radar) version of the ARSCL (Active Remotely-Sensed Cloud Locations) Value Added Product (VAP) is available. The MERGESONDE VAP is utilized where temperature and humidity profiles are required. Future additions to this dataset will utilize the new KAZR instrument and its associated VAPs.

  10. Cloud Properties and Radiative Heating Rates for TWP

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Comstock, Jennifer

    A cloud properties and radiative heating rates dataset is presented where cloud properties retrieved using lidar and radar observations are input into a radiative transfer model to compute radiative fluxes and heating rates at three ARM sites located in the Tropical Western Pacific (TWP) region. The cloud properties retrieval is a conditional retrieval that applies various retrieval techniques depending on the available data, that is if lidar, radar or both instruments detect cloud. This Combined Remote Sensor Retrieval Algorithm (CombRet) produces vertical profiles of liquid or ice water content (LWC or IWC), droplet effective radius (re), ice crystal generalized effective size (Dge), cloud phase, and cloud boundaries. The algorithm was compared with 3 other independent algorithms to help estimate the uncertainty in the cloud properties, fluxes, and heating rates (Comstock et al. 2013). The dataset is provided at 2 min temporal and 90 m vertical resolution. The current dataset is applied to time periods when the MMCR (Millimeter Cloud Radar) version of the ARSCL (Active Remotely-Sensed Cloud Locations) Value Added Product (VAP) is available. The MERGESONDE VAP is utilized where temperature and humidity profiles are required. Future additions to this dataset will utilize the new KAZR instrument and its associated VAPs.

  11. Characteristics of a Marine Stratocumulus to Cumulus Cloud Transition

    E-Print Network [OSTI]

    Zapalac, Allison

    2014-12-08T23:59:59.000Z

    The studies in this thesis aim to improve the overall understanding of the characteristics of the marine stratocumulus to shallow cumulus transition over the southeast Pacific Ocean. This study uses observations from CloudSat and CALIPSO satellite...

  12. Migrating enterprise storage applications to the cloud

    E-Print Network [OSTI]

    Vrable, Michael Daniel

    2011-01-01T23:59:59.000Z

    2.1 Cloud Providers . . . . . . . . . . . .2.1.1 Cloud Storage . . . . . . . . .2.1.2 Cloud Computation . . . . . . 2.2 Enterprise Storage

  13. A developer's survey on different cloud platforms

    E-Print Network [OSTI]

    Doan, Dzung

    2009-01-01T23:59:59.000Z

    1 Introduction Cloud computing is a computing paradigm inFor this reason, cloud computing has also been describedparallel processing. Cloud computing can be contrasted with

  14. AEROSOL, CLOUDS, AND CLIMATE CHANGE

    SciTech Connect (OSTI)

    SCHWARTZ, S.E.

    2005-09-01T23:59:59.000Z

    Earth's climate is thought to be quite sensitive to changes in radiative fluxes that are quite small in absolute magnitude, a few watts per square meter, and in relation to these fluxes in the natural climate. Atmospheric aerosol particles exert influence on climate directly, by scattering and absorbing radiation, and indirectly by modifying the microphysical properties of clouds and in turn their radiative effects and hydrology. The forcing of climate change by these indirect effects is thought to be quite substantial relative to forcing by incremental concentrations of greenhouse gases, but highly uncertain. Quantification of aerosol indirect forcing by satellite- or ground-based remote sensing has proved quite difficult in view of inherent large variation in the pertinent observables such as cloud optical depth, which is controlled mainly by liquid water path and only secondarily by aerosols. Limited work has shown instances of large magnitude of aerosol indirect forcing, with local instantaneous forcing upwards of 50 W m{sup 66}-2. Ultimately it will be necessary to represent aerosol indirect effects in climate models to accurately identify the anthropogenic forcing at present and over secular time and to assess the influence of this forcing in the context of other forcings of climate change. While the elements of aerosol processes that must be represented in models describing the evolution and properties of aerosol particles that serve as cloud condensation particles are known, many important components of these processes remain to be understood and to be represented in models, and the models evaluated against observation, before such model-based representations can confidently be used to represent aerosol indirect effects in climate models.

  15. Covered Product Category: Commercial Fryers

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial fryers, which is a product category covered by the ENERGY STAR program.

  16. Covered Product Category: Commercial Griddles

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial griddles, which is a product category covered by the ENERGY STAR program

  17. High-velocity clouds: a diverse phenomenon

    E-Print Network [OSTI]

    B. P. Wakker

    2001-09-13T23:59:59.000Z

    In this contribution the current state of knowledge about the high-velocity clouds (HVCs) is summarized. Recent progress has shown that the HVCs are a diverse phenomenon. The intermediate-velocity clouds (IVCs) are likely to be part of a Galactic Fountain. The Magellanic Stream is a tidal remnant. HVC complex C (possibly complexes A and GCN) are low-metallicity clouds near the Galaxy; they could be remnants of the formation of the Galaxy or old tidal streams extracted from nearby dwarf galaxies. Having a substantial number of HI HVCs dispersed throughout the Local Group seems incompatible with the observed HI mass function of galaxies. Finally, FUSE finds high-velocity OVI, some of which is clearly associated with HI HVCs, but some which is not.

  18. Cirrus clouds in a global climate model with a statistical cirrus cloud scheme

    SciTech Connect (OSTI)

    Wang, Minghuai; Penner, Joyce E.

    2010-06-21T23:59:59.000Z

    A statistical cirrus cloud scheme that accounts for mesoscale temperature perturbations is implemented in a coupled aerosol and atmospheric circulation model to better represent both subgrid-scale supersaturation and cloud formation. This new scheme treats the effects of aerosol on cloud formation and ice freezing in an improved manner, and both homogeneous freezing and heterogeneous freezing are included. The scheme is able to better simulate the observed probability distribution of relative humidity compared to the scheme that was implemented in an older version of the model. Heterogeneous ice nuclei (IN) are shown to decrease the frequency of occurrence of supersaturation, and improve the comparison with observations at 192 hPa. Homogeneous freezing alone can not reproduce observed ice crystal number concentrations at low temperatures (<205 K), but the addition of heterogeneous IN improves the comparison somewhat. Increases in heterogeneous IN affect both high level cirrus clouds and low level liquid clouds. Increases in cirrus clouds lead to a more cloudy and moist lower troposphere with less precipitation, effects which we associate with the decreased convective activity. The change in the net cloud forcing is not very sensitive to the change in ice crystal concentrations, but the change in the net radiative flux at the top of the atmosphere is still large because of changes in water vapor. Changes in the magnitude of the assumed mesoscale temperature perturbations by 25% alter the ice crystal number concentrations and the net radiative fluxes by an amount that is comparable to that from a factor of 10 change in the heterogeneous IN number concentrations. Further improvements on the representation of mesoscale temperature perturbations, heterogeneous IN and the competition between homogeneous freezing and heterogeneous freezing are needed.

  19. NEGLECTED CLOUDS IN T AND Y DWARF ATMOSPHERES

    SciTech Connect (OSTI)

    Morley, Caroline V.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Marley, Mark S. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Visscher, Channon [Southwest Research Institute, Boulder, CO 80302 (United States); Saumon, Didier [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Leggett, S. K., E-mail: cmorley@ucolick.org [Gemini Observatory, Northern Operations Center, Hilo, HI 96720 (United States)

    2012-09-10T23:59:59.000Z

    As brown dwarfs cool, a variety of species condense in their atmospheres, forming clouds. Iron and silicate clouds shape the emergent spectra of L dwarfs, but these clouds dissipate at the L/T transition. A variety of other condensates are expected to form in cooler T dwarf atmospheres. These include Cr, MnS, Na{sub 2}S, ZnS, and KCl, but the opacity of these optically thinner clouds has not been included in previous atmosphere models. Here, we examine their effect on model T and Y dwarf atmospheres. The cloud structures and opacities are calculated using the Ackerman and Marley cloud model, which is coupled to an atmosphere model to produce atmospheric pressure-temperature profiles in radiative-convective equilibrium. We generate a suite of models between T{sub eff} = 400 and 1300 K, log g = 4.0 and 5.5, and condensate sedimentation efficiencies from f{sub sed} = 2 to 5. Model spectra are compared to two red T dwarfs, Ross 458C and UGPS 0722-05; models that include clouds are found to match observed spectra significantly better than cloudless models. The emergence of sulfide clouds in cool atmospheres, particularly Na{sub 2}S, may be a more natural explanation for the 'cloudy' spectra of these objects, rather than the reemergence of silicate clouds that wane at the L-to-T transition. We find that sulfide clouds provide a mechanism to match the near- and mid-infrared colors of observed T dwarfs. Our results indicate that including the opacity of condensates in T dwarf atmospheres is necessary to accurately determine the physical characteristics of many of the observed objects.

  20. Triggered star formation in the Magellanic Clouds

    E-Print Network [OSTI]

    B. G. Elmegreen; J. Palous; Kenji Bekki

    2006-01-01T23:59:59.000Z

    Abstract. We discuss how tidal interaction between the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the Galaxy triggers galaxy-wide star formation in the Clouds for the last ? 0.2 Gyr based on our chemodynamical simulations on the Clouds. Our simulations demonstrate that the tidal interaction induces the formation of asymmetric spiral arms with high gas densities and consequently triggers star formation within the arms in the LMC. Star formation rate in the present LMC is significantly enhanced just above the eastern edge of the LMC’s stellar bar owing to the tidal interaction. The location of the enhanced star formation is very similar to the observed location of 30 Doradus, which suggests that the formation of 30 Doradus is closely associated with the last Magellanic collision about 0.2 Gyr ago. The tidal interaction can dramatically compress gas initially within the outer part of the SMC so that new stars can be formed from the gas to become intergalactic young stars in the inter-Cloud region (e.g., the Magellanic Bridge). The metallicity distribution function of the newly formed stars in the Magellanic Bridge has a peak of [Fe/H] ? ?0.8, which is significantly lower than the stellar metallicity of the SMC.

  1. Study of Electron Cloud for MEIC

    SciTech Connect (OSTI)

    S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn

    2011-09-01T23:59:59.000Z

    The Medium Energy Electron Ion Collider (MEIC) at Jefferson Lab has been envisioned as a future high energy particle accelerator beyond the 12 GeV upgrade of the existing Continuous Electron Beam Accelerator Facility (CEBAF). Synchrotron radiation from the closely spaced proton bunches in MEIC can generate photoelectrons inside the vacuum chamber and cause secondary emission due to multipacting in the presence of beam's electric field. This phenomenon can lead to fast build up of electron density, known as electron cloud effect - resulting into beam instability coupled to multi-bunches in addition to a single bunch. For MEIC, the estimated threshold value of the electron-cloud density is approximately 5 x 10{sup 12} m{sup -3}. In this paper, we would like to report the self-consistent simulation studies of electron cloud formation for MEIC. The code has been benchmarked against the published data of electron cloud effects observed in LHC. Our first simulations predict increase of electron clouds with the increase of repetition rate. The detailed simulations are under progress and will be reported.

  2. Tropical Warm Pool International Cloud Experiment TWP-ICE Cloud and rain characteristics in the Australian Monsoon

    SciTech Connect (OSTI)

    May, P.T., Jakob, C., and Mather, J.H.

    2004-05-31T23:59:59.000Z

    The impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them.

  3. Long-term impacts of aerosols on vertical development of cloud and precipitation

    SciTech Connect (OSTI)

    Li Z.; Liu Y.; Niu, F.; Fan, J.; Rosenfeld, D.; Ding, Y.

    2011-11-13T23:59:59.000Z

    Aerosols alter cloud density and the radiative balance of the atmosphere. This leads to changes in cloud microphysics and atmospheric stability, which can either suppress or foster the development of clouds and precipitation. The net effect is largely unknown, but depends on meteorological conditions and aerosol properties. Here, we examine the long-term impact of aerosols on the vertical development of clouds and rainfall frequencies, using a 10-year dataset of aerosol, cloud and meteorological variables collected in the Southern Great Plains in the United States. We show that cloud-top height and thickness increase with aerosol concentration measured near the ground in mixed-phase clouds-which contain both liquid water and ice-that have a warm, low base. We attribute the effect, which is most significant in summer, to an aerosol-induced invigoration of upward winds. In contrast, we find no change in cloud-top height and precipitation with aerosol concentration in clouds with no ice or cool bases. We further show that precipitation frequency and rain rate are altered by aerosols. Rain increases with aerosol concentration in deep clouds that have a high liquid-water content, but declines in clouds that have a low liquid-water content. Simulations using a cloud-resolving model confirm these observations. Our findings provide unprecedented insights of the long-term net impacts of aerosols on clouds and precipitation.

  4. Development of an objective method for forecasting "Gulf" stratus clouds at Bryan Air Base, Texas, in the summer season

    E-Print Network [OSTI]

    Jenrette, James Prentiss

    1958-01-01T23:59:59.000Z

    slopes in producing the stratus clouds, He also indicated that, in general, the presence of high clouds is fairly well correlated wtth nonexistence of stratus. Another important factor, ground ventilation, was discussed by Decker (32), In a study... radiation, up- slope movement of the prevailing wind, ground ventilation, and high cloud cover are factors that must be considered in solving the stratus problem. Obviously it would be difficulty if not impossible, to incor- porate parameters...

  5. A Parameterized Microwace Emission Model for Dry Snow Cover Lingmei JIANG1,2,3

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    , and the measurements can be carried out through cloud cover. When snow starts to melt, emission will significantly the vector radiative transfer equations to include the multi-scattering effects. This model uses 1) the dense the Dense Media Radiative Transfer Model (DMRT) and AIEM to simulation of dry snow emission with Matrix

  6. NOAA Technical Memorandum ERL GLERL-Y AN ANALYSIS OF GREAT LAKES ICE COVER

    E-Print Network [OSTI]

    ~ecting the passes to be used were: amount of cloud cover, availability of ground verification data, and number and the primary modes of interaction with incident radiation with respect to the satellite sensor. Table 3, and the path radiance. These effects mu*t be calculated for each frame; this can be achieved by measuring

  7. The Formation of the Oort Cloud in Open Cluster Environments

    E-Print Network [OSTI]

    Nathan A. Kaib; Thomas Quinn

    2008-04-02T23:59:59.000Z

    We study the influence of an open cluster environment on the formation and current structure of the Oort cloud. To do this, we have run 19 different simulations of the formation of the Oort Cloud for 4.5 Gyrs. In each simulation, the solar system spends its first 100 Myrs in a different open cluster environment before transitioning to its current field environment. We find that, compared to forming in the field environment, the inner Oort Cloud is preferentially loaded with comets while the Sun resides in the open cluster and that most of this material remains locked in the interior of the cloud for the next 4.4 Gyrs. In addition, the outer Oort Cloud trapping efficiencies we observe in our simulations are lower than previous formation models by about a factor of 2, possibly implying an even more massive early planetesimal disk. Furthermore, some of our simulations reproduce the orbits of observed extended scattered disk objects, which may serve as an observational constraint on the Sun's early environment. Depending on the particular open cluster environment, the properties of the inner Oort Cloud and extended scattered disk can vary widely. On the other hand, the outer portions of the Oort Cloud in each of our simulations are all similar.

  8. Simulations of Arctic Mixed-Phase Clouds in Forecasts with CAM3 and AM2 for M-PACE

    SciTech Connect (OSTI)

    Xie, Shaocheng; Boyle, James; Klein, Stephen A.; Liu, Xiaohong; Ghan, Steven J.

    2008-02-29T23:59:59.000Z

    Simulations of mixed-phase clouds in short-range forecasts with the National Center for Atmospheric Research Community Atmosphere Model version 3 (CAM3) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model (AM2) for the Mixed-Phase Arctic Cloud Experiment (M-PACE) are performed under the DOE CCPP-ARM Parameterization Testbed (CAPT), which initializes the climate models with analysis data produced from numerical weather prediction (NWP) centers. It is shown that CAM3 significantly underestimates the observed boundary layer mixed-phase clouds and cannot realistically simulate the variations with temperature and cloud height of liquid water fraction in the total cloud condensate based an oversimplified cloud microphysical scheme. In contrast, AM2 reasonably reproduces the observed boundary layer clouds while its clouds contain much less cloud condensate than CAM3 and the observations. Both models underestimate the observed cloud top and base for the boundary layer clouds. The simulation of the boundary layer mixed-phase clouds and their microphysical properties is considerably improved in CAM3 when a new physically based cloud microphysical scheme is used. The new scheme also leads to an improved simulation of the surface and top of the atmosphere longwave radiative fluxes in CAM3. It is shown that the Bergeron-Findeisen process, i.e., the ice crystal growth by vapor deposition at the expense of coexisting liquid water, is important for the models to correctly simulate the characteristics of the observed microphysical properties in mixed-phase clouds. Sensitivity tests show that these results are not sensitive to the analysis data used for model initializations. Increasing model horizontal resolution helps capture the subgrid-scale features in Arctic frontal clouds but does not help improve the simulation of the single-layer boundary layer clouds. Ice crystal number density has large impact on the model simulated mixed-phase clouds and their microphysical properties and needs to be accurately represented in climate models.

  9. Ice Heating Up Cold Clouds | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ice Heating Up Cold Clouds Ice Heating Up Cold Clouds Released: October 04, 2011 In a heated battle, ice crystals win the competition for cloud water vapor The mighty cloud ice...

  10. Cloud Based Applications and Platforms (Presentation)

    SciTech Connect (OSTI)

    Brodt-Giles, D.

    2014-05-15T23:59:59.000Z

    Presentation to the Cloud Computing East 2014 Conference, where we are highlighting our cloud computing strategy, describing the platforms on the cloud (including Smartgrid.gov), and defining our process for implementing cloud based applications.

  11. Characterization of melting level clouds over the tropical western pacific warm pool

    SciTech Connect (OSTI)

    Jensen, M.; Johnson, K.; Billings, J.; Troyan, D.; Long, C.; Comstock, J.

    2010-03-15T23:59:59.000Z

    A cursory examination of historical ARSCL data indicates a common cloud feature in the tropics are thin detrainment shelves (Attendant Shelf Clouds, or ASCs) near the melting level (see figure for example). We use the ARSCL product to identify ASCs by defining them as cloud layers with bases above 4 km, a corresponding top below 6 km, and a thickness of less than 1 km. In order to prevent biases in determination of the diurnal cycle of cloud occurrence, we require that both the MMCR and MPL are operating well. In this study we use a total of 55 months of data collected over 14 years of deployments at the Manus, Nauru, and Darwin ARM sites in the Tropical Western Pacific to define the frequency of occurrence (~ 14% of the time) and diurnal cycle of these clouds, along with the atmospheric thermodynamic profile. We further investigate the horizontal extent, cloud radiative forcing, and cloud particle phase through a series of “golden cases” where there is a general absence of additional cloud types in the column and nearby deep convection. These cases indicate that the clouds can cover horizontal areas on the order of a GCM gridbox, have significant (but not always) cloud radiative forcing, and may be composed of liquid or ice water.

  12. Weather in stellar atmosphere: the dynamics of mercury clouds in alpha Andromedae

    E-Print Network [OSTI]

    Oleg Kochukhov; Saul J. Adelman; Austin F. Gulliver; Nikolai Piskunov

    2007-05-30T23:59:59.000Z

    The formation of long-lasting structures at the surfaces of stars is commonly ascribed to the action of strong magnetic fields. This paradigm is supported by observations of evolving cool spots in the Sun and active late-type stars, and stationary chemical spots in the early-type magnetic stars. However, results of our seven-year monitoring of mercury spots in non-magnetic early-type star alpha Andromedae show that the picture of magnetically-driven structure formation is fundamentally incomplete. Using an indirect stellar surface mapping technique, we construct a series of 2-D images of starspots and discover a secular evolution of the mercury cloud cover in this star. This remarkable structure formation process, observed for the first time in any star, is plausibly attributed to a non-equilibrium, dynamical evolution of the heavy-element clouds created by atomic diffusion and may have the same underlying physics as the weather patterns on terrestrial and giant planets.

  13. Modeling Incoherent Electron Cloud Effects

    E-Print Network [OSTI]

    Benedetto, E.

    2008-01-01T23:59:59.000Z

    electron-cloud effects and synchrotron radiation can lead toelectron-cloud effects and synchrotron radiation can lead tocloud phenomena in positrons storage rings the effect of syn- chrotron radiation

  14. INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE

    SciTech Connect (OSTI)

    Demory, Brice-Olivier; De Wit, Julien; Lewis, Nikole; Zsom, Andras; Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)] [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Fortney, Jonathan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)] [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Knutson, Heather; Desert, Jean-Michel [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)] [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Heng, Kevin [Center for Space and Habitability, University of Bern, Sidlerstrasse 5, CH-3012, Bern (Switzerland)] [Center for Space and Habitability, University of Bern, Sidlerstrasse 5, CH-3012, Bern (Switzerland); Madhusudhan, Nikku [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06520 (United States)] [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Gillon, Michael [Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, 17, Bat. B5C, B-4000 Liège 1 (Belgium)] [Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, 17, Bat. B5C, B-4000 Liège 1 (Belgium); Barclay, Thomas [NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States)] [NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States); Parmentier, Vivien [Laboratoire J.-L. Lagrange, UMR 7293, Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur B.P. 4229, F-06304 Nice Cedex 4 (France)] [Laboratoire J.-L. Lagrange, UMR 7293, Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur B.P. 4229, F-06304 Nice Cedex 4 (France); Cowan, Nicolas B., E-mail: demory@mit.edu [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, F165, Evanston, IL 60208 (United States)

    2013-10-20T23:59:59.000Z

    We present new visible and infrared observations of the hot Jupiter Kepler-7b to determine its atmospheric properties. Our analysis allows us to (1) refine Kepler-7b's relatively large geometric albedo of Ag = 0.35 ± 0.02, (2) place upper limits on Kepler-7b thermal emission that remains undetected in both Spitzer bandpasses and (3) report a westward shift in the Kepler optical phase curve. We argue that Kepler-7b's visible flux cannot be due to thermal emission or Rayleigh scattering from H{sub 2} molecules. We therefore conclude that high altitude, optically reflective clouds located west from the substellar point are present in its atmosphere. We find that a silicate-based cloud composition is a possible candidate. Kepler-7b exhibits several properties that may make it particularly amenable to cloud formation in its upper atmosphere. These include a hot deep atmosphere that avoids a cloud cold trap, very low surface gravity to suppress cloud sedimentation, and a planetary equilibrium temperature in a range that allows for silicate clouds to potentially form in the visible atmosphere probed by Kepler. Our analysis does not only present evidence of optically thick clouds on Kepler-7b but also yields the first map of clouds in an exoplanet atmosphere.

  15. A study of the Orion cometary cloud L1616

    E-Print Network [OSTI]

    B. Ramesh

    1995-05-27T23:59:59.000Z

    With its cometary appearance and a reflection nebula near its edge facing some bright Orion stars, the Lynd's cloud L1616 shows ample evidence for being affected by one or more of these massive stars. To estimate its mass and star formation efficiency as well as to determine if it is gravitationally bound, we mapped this cloud in J=1${\\rightarrow}$0 transitions of $^{12}$CO and $^{13}$CO. It is found that the distribution of the emission in the line {\\it wings} show clear evidence for substantial mass motions. Also, the ``virial'' mass of the cloud is found to be five times the actual cloud mass determined from the $^{13}$CO column density map. It is argued that this cloud has abnormally high star formation efficiency and is possibly disintegrating. The morphology and the location of the cloud indicate that it is being affected by the star ${\\epsilon}$ Orionis which is also possibly responsible for the cloud's unusual star formation efficiency. Over a range of values of the relevant parameters, the star is found to quantitatively satisfy the requirements of being the cause of the observed characteristics of the cloud.

  16. Secure Cloud Computing With Brokered Trusted

    E-Print Network [OSTI]

    ) ·Audio ·QualComm 7201 528MHZ ·64MB Ram ·MicroSD Slow Storage ·Currently NO SIM CHIPS Monday, March 29 External Storage External Storage Router Router Router Router Cloud Computing Cloud Computing Cloud Storage External Storage Router Router Router Router Cloud Computing Cloud Computing Cloud Computing Tower

  17. The Intrinsic Shapes of Molecular Cloud Fragments over a Range of Length Scales

    E-Print Network [OSTI]

    C. E. Jones; Shantanu Basu

    2001-12-19T23:59:59.000Z

    We decipher intrinsic three-dimensional shape distributions of molecular clouds, cloud cores, Bok globules, and condensations using recently compiled catalogues of observed axis ratios for these objects mapped in carbon monoxide, ammonia, through optical selection, or in continuum dust emission. We apply statistical techniques to compare assumed intrinsic axis ratio distributions with observed projected axis ratio distributions. Intrinsically triaxial shapes produce projected distributions which agree with observations. Molecular clouds mapped in $^{12}$CO are intrinsically triaxial but more nearly prolate than oblate, while the smaller cloud cores, Bok globules, and condensations are also intrinsically triaxial but more nearly oblate than prolate.

  18. Opaque cloud detection

    DOE Patents [OSTI]

    Roskovensky, John K. (Albuquerque, NM)

    2009-01-20T23:59:59.000Z

    A method of detecting clouds in a digital image comprising, for an area of the digital image, determining a reflectance value in at least three discrete electromagnetic spectrum bands, computing a first ratio of one reflectance value minus another reflectance value and the same two values added together, computing a second ratio of one reflectance value and another reflectance value, choosing one of the reflectance values, and concluding that an opaque cloud exists in the area if the results of each of the two computing steps and the choosing step fall within three corresponding predetermined ranges.

  19. Command Line Tools Cloud Computing

    E-Print Network [OSTI]

    Ferrara, Katherine W.

    Command Line Tools Cloud Computing #12;Everybody (or nearly everybody) loves GUI. AWS Command Line of advanced features. After surviving the cloud computing class till now, Your are almost a command line guru! You need AWS command line tools, ec2-api-tools, to maximize the power of AWS cloud computing. Plugging

  20. 8, 96979729, 2008 FRESCO+ cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 9697­9729, 2008 FRESCO+ cloud retrieval algorithm P. Wang et al. Title Page Abstract Chemistry and Physics Discussions FRESCO+: an improved O2 A-band cloud retrieval algorithm for tropospheric on behalf of the European Geosciences Union. 9697 #12;ACPD 8, 9697­9729, 2008 FRESCO+ cloud retrieval

  1. 3, 33013333, 2003 Cirrus cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 3, 3301­3333, 2003 Cirrus cloud occurrence as function of ambient relative humidity J. Str and Physics Discussions Cirrus cloud occurrence as function of ambient relative humidity: A comparison¨om (johan@itm.su.se) 3301 #12;ACPD 3, 3301­3333, 2003 Cirrus cloud occurrence as function of ambient

  2. Cloud Formation, Evolution and Destruction

    E-Print Network [OSTI]

    Estalella, Robert

    Chapter 4 Cloud Formation, Evolution and Destruction We now begin to trace the journey towards a star. How long does this take? The answer is surprisingly short: a good many clouds already contain new stars and these stars tend to be young. The typical cloud cannot spend long, if any time at all

  3. 5, 60136039, 2005 FRESCO cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 5, 6013­6039, 2005 FRESCO cloud algorithm N. Fournier et al. Title Page Abstract Introduction cloud information over deserts from SCIAMACHY O2 A-band N. Fournier 1 , P. Stammes 1 , M. de Graaf 1 , R, 6013­6039, 2005 FRESCO cloud algorithm N. Fournier et al. Title Page Abstract Introduction Conclusions

  4. NIST Cloud Computing Reference Architecture

    E-Print Network [OSTI]

    Perkins, Richard A.

    NIST Cloud Computing Reference Architecture Recommendations of the National Institute of Standards Publication 500-292 #12;i NIST Special Publication 500-292 NIST Cloud Computing Reference Architecture, John Messina, Lee Badger and Dawn Leaf Information Techonology Laboratory Cloud Computing Program

  5. Cover Crops for the Garden

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    matter for your soil or compost pile. Organic matter is thatin the spring or made into compost, cover crops will act asgathered up and added to your compost pile. The first method

  6. Stratocumulus Clouds ROBERT WOOD

    E-Print Network [OSTI]

    Wood, Robert

    by latent heating in updrafts and cooling in downdrafts. Turbulent eddies and evaporative cooling drives, stratification of the STBL, and in some cases cloud breakup. Feedbacks between radiative cooling, precipitation- way interactions may be a key driver of aerosol concentrations over the remote oceans. Aerosol

  7. Estimated probability of the partial coverage of QSOs by intervening H2-clouds at formation of QSO

    E-Print Network [OSTI]

    of the effect may change significantly physical parameters of interstellar clouds derived from the spectral the observer to the centres of QSO and cloud. q is a solid angle (light cone) of the whole BLR radiation fluxEstimated probability of the partial coverage of QSOs by intervening H2-clouds at formation of QSO

  8. Dynamic Effects on the Tropical Cloud Radiative Forcing and Radiation Budget JIAN YUAN, DENNIS L. HARTMANN, AND ROBERT WOOD

    E-Print Network [OSTI]

    Wood, Robert

    Dynamic Effects on the Tropical Cloud Radiative Forcing and Radiation Budget JIAN YUAN, DENNIS L to isolate the effect of large-scale dynamics on the observed radiation budget and cloud properties the Earth Radiation Budget Experiment (ERBE) show that the net radiative effect of clouds on the earth

  9. Cloud climatology at the Southern Great Plains and the layer structure, drizzle, and atmospheric modes of continental stratus

    E-Print Network [OSTI]

    of cloud layers, an issue that is important in calculating both the radiative and the hydro- logic effects.5 years) cloud observations from the Atmospheric Radiation Measurements (ARM) program Southern Great in Global Climate Models (GCMs) remains a source of uncertainty in climate simulations. Cloud climatologies

  10. Computing and Partitioning Cloud Feedbacks Using Cloud Property Histograms. Part I: Cloud Radiative Kernels

    E-Print Network [OSTI]

    Hartmann, Dennis

    radiative forcing. The global and annual mean model-simulated cloud feedback is dominated by contributions to a hypothetical cloudless but other- wise identical planet, the global and annual mean effect of clouds at the top is how cloud radiative effects will change as the planet warms because of long-lived greenhouse gases

  11. Ice Formation in Arctic Mixed-Phase Clouds: Insights from a 3-D Cloud-Resolving Model with Size-Resolved Aerosol and Cloud Microphysics

    SciTech Connect (OSTI)

    Fan, Jiwen; Ovtchinnikov, Mikhail; Comstock, Jennifer M.; McFarlane, Sally A.; Khain, Alexander

    2009-02-27T23:59:59.000Z

    The single-layer mixed-phase clouds observed during the Atmospheric Radiation Measurement (ARM) program’s Mixed-Phase Arctic Cloud Experiment (MPACE) are simulated with a 3-dimensional cloud-resolving model the System for Atmospheric Modeling (SAM) coupled with an explicit bin microphysics scheme and a radar-lidar simulator. Two possible ice enhancement mechanisms – activation of droplet evaporation residues by condensation-followed-by-freezing and droplet freezing by contact freezing inside-out, are scrutinized by extensive comparisons with aircraft and radar and lidar measurements. The locations of ice initiation associated with each mechanism and the role of ice nuclei (IN) in the evolution of mixed-phase clouds are mainly addressed. Simulations with either mechanism agree well with the in-situ and remote sensing measurements on ice microphysical properties but liquid water content is slightly underpredicted. These two mechanisms give very similar cloud microphysical, macrophysical, dynamical, and radiative properties, although the ice nucleation properties (rate, frequency and location) are completely different. Ice nucleation from activation of evaporation nuclei is most efficient near cloud top areas concentrated on the edges of updrafts, while ice initiation from the drop freezing process has no significant location preference (occurs anywhere that droplet evaporation is significant). Both enhanced nucleation mechanisms contribute dramatically to ice formation with ice particle concentration of 10-15 times higher relative to the simulation without either of them. The contribution of ice nuclei (IN) recycling from ice particle evaporation to IN and ice particle concentration is found to be very significant in this case. Cloud can be very sensitive to IN initially and form a nonquilibrium transition condition, but become much less sensitive as cloud evolves to a steady mixed-phase condition. The parameterization of Meyers et al. [1992] with the observed MPACE IN concentration is able to predict the observed mixed-phase clouds reasonably well. This validation may facilitate the application of this parameterization in the cloud and climate models to simulate Arctic clouds.

  12. Cover

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011AT&T, Inc.'sEnergyTexas1.SpaceFluorControlsEnergy Copyin Salt |Course

  13. Cover

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613PortsmouthBartlesvilleAbout » Contact Us ContactPractices inCostsCourse Overview

  14. cover

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron4 Self-Scrubbing:,, , ., ..., ,+ .

  15. MAGIC: Marine ARM GPCI Investigation of Clouds

    SciTech Connect (OSTI)

    Lewis, ER; Wiscombe, WJ; Albrecht, BA; Bland, GL; Flagg, CN; Klein, SA; Kollias, P; Mace, G; Reynolds, RM; Schwartz, SE; Siebesma, AP; Teixeira, J; Wood, R; Zhang, M

    2012-10-03T23:59:59.000Z

    The second Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF2) will be deployed aboard the Horizon Lines cargo container ship merchant vessel (M/V) Spirit for MAGIC, the Marine ARM GPCI1 Investigation of Clouds. The Spirit will traverse the route between Los Angeles, California, and Honolulu, Hawaii, from October 2012 through September 2013 (except for a few months in the middle of this time period when the ship will be in dry dock). During this field campaign, AMF2 will observe and characterize the properties of clouds and precipitation, aerosols, and atmospheric radiation; standard meteorological and oceanographic variables; and atmospheric structure. There will also be two intensive observational periods (IOPs), one in January 2013 and one in July 2013, during which more detailed measurements of the atmospheric structure will be made.

  16. EA-1852: Cloud County Community College Wind Energy Project,...

    Broader source: Energy.gov (indexed) [DOE]

    2: Cloud County Community College Wind Energy Project, Cloud County, Kansas EA-1852: Cloud County Community College Wind Energy Project, Cloud County, Kansas Summary This EA...

  17. CloudAnalyst: A CloudSim-based Visual Modeller for Analysing Cloud Computing Environments and Applications

    E-Print Network [OSTI]

    Calheiros, Rodrigo N.

    CloudAnalyst: A CloudSim-based Visual Modeller for Analysing Cloud Computing Environments and Applications Bhathiya Wickremasinghe1 , Rodrigo N. Calheiros2 , and Rajkumar Buyya1 1 The Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computer Science and Software Engineering The University

  18. CloudSat Overview CloudSat will provide, from space, the first global survey of cloud profiles and

    E-Print Network [OSTI]

    on the radiative and water budgets of clouds are broadly referred to as indirect aerosol effects. The aerosol processes and their accumulated effects on the global scale. 2. Mission Description CloudSat is plannedCloudSat Overview CloudSat will provide, from space, the first global survey of cloud profiles

  19. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01T23:59:59.000Z

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  20. The Launching of Cold Clouds by Galaxy Outflows I: Hydrodynamic Interactions with Radiative Cooling

    E-Print Network [OSTI]

    Scannapieco, Evan

    2015-01-01T23:59:59.000Z

    To better understand the nature of the multiphase material found in outflowing galaxies, we study the evolution of cold clouds embedded in flows of hot and fast material. Using a suite of adaptive-mesh refinement simulations that include radiative cooling, we investigate both cloud mass loss and cloud acceleration under the full range of conditions observed in galaxy outflows. The simulations are designed to track the cloud center of mass, enabling us to study the cloud evolution at long disruption times. For supersonic flows, a Mach cone forms around the cloud, which damps the Kelvin-Helmholtz instability but also establishes a streamwise pressure gradient that stretches the cloud apart. If time is expressed in units of the cloud crushing time, both the cloud lifetime and the cloud acceleration rate are independent of cloud radius, and we find simple scalings for these quantities as a function of the Mach number of the external medium. A resolution study suggests that our simulations have sufficient resoluti...

  1. The Near-infrared Period-luminosity Relations of Cepheids in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Mahzooni, Salma

    2011-08-08T23:59:59.000Z

    We present near-infrared (J & Ks) observations of Cepheids in the Large Magellanic Cloud. The goals of these observations are to better characterize the Cepheid Period-Luminosity relation at these wavelengths, especially for periods below 10 days...

  2. A Catalog of HI Clouds in the Large Magellanic Cloud

    E-Print Network [OSTI]

    S. Kim; E. Rosolowsky; Y. Lee; Y. Kim; Y. C. Jung; M. A. Dopita; B. G. Elmegreen; K. C. Freeman; R. J. Sault; M. J. Kesteven; D. McConnell; Y. -H. Chu

    2007-06-28T23:59:59.000Z

    A 21 cm neutral hydrogen interferometric survey of the Large Magellanic Cloud (LMC) combined with the Parkes multi-beam HI single-dish survey clearly shows that the HI gas is distributed in the form of clumps or clouds. The HI clouds and clumps have been identified using a thresholding method with three separate brightness temperature thresholds ($T_b$). Each catalog of HI cloud candidates shows a power law relationship between the sizes and the velocity dispersions of the clouds roughly following the Larson Law scaling $\\sigma_v \\propto R^{0.5}$, with steeper indices associated with dynamically hot regions. The clouds in each catalog have roughly constant virial parameters as a function mass suggesting that that the clouds are all in roughly the same dynamical state, but the values of the virial parameter are significantly larger than unity showing that turbulent motions dominate gravity in these clouds. The mass distribution of the clouds is a power law with differential indices between -1.6 and -2.0 for the three catalogs. In contrast, the distribution of mean surface densities is a log-normal distribution.

  3. Covered Product Category: Imaging Equipment

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including imaging equipment, which is covered by the ENERGY STAR® program. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  4. Deans Audit Cover Environmental Compliance

    E-Print Network [OSTI]

    Pawlowski, Wojtek

    facilities in central New York to comply with a New York State Department of Environmental Conservation (DECDeans Audit Cover Environmental Compliance Guidance Document Approved by: (Pat McNally) Last electronically at: http://sp.ehs.cornell.edu/env/general-environmental-management/environmental

  5. Constructing a Merged Cloud-Precipitation Radar Dataset for Tropical Convective Clouds during the DYNAMO/AMIE Experiment at Addu Atoll

    SciTech Connect (OSTI)

    Feng, Zhe; McFarlane, Sally A.; Schumacher, Courtney; Ellis, Scott; Comstock, Jennifer M.; Bharadwaj, Nitin

    2014-05-16T23:59:59.000Z

    To improve understanding of the convective processes key to the Madden-Julian-Oscillation (MJO) initiation, the Dynamics of the MJO (DYNAMO) and Atmospheric Radiation Measurement MJO Investigation Experiment (AMIE) collected four months of observations from three radars, the S-band Polarization Radar (S-Pol), the C-band Shared Mobile Atmospheric Research & Teaching Radar (SMART-R), and Ka-band Zenith Radar (KAZR) on Addu Atoll in the tropical Indian Ocean. This study compares the measurements from the S-Pol and SMART-R to those from the more sensitive KAZR in order to characterize the hydrometeor detection capabilities of the two scanning precipitation radars. Frequency comparisons for precipitating convective clouds and non-precipitating high clouds agree much better than non-precipitating low clouds for both scanning radars due to issues in ground clutter. On average, SMART-R underestimates convective and high cloud tops by 0.3 to 1.1 km, while S-Pol underestimates cloud tops by less than 0.4 km for these cloud types. S-Pol shows excellent dynamic range in detecting various types of clouds and therefore its data are well suited for characterizing the evolution of the 3D cloud structures, complementing the profiling KAZR measurements. For detecting non-precipitating low clouds and thin cirrus clouds, KAZR remains the most reliable instrument. However, KAZR is attenuated in heavy precipitation and underestimates cloud top height due to rainfall attenuation 4.3% of the time during DYNAMO/AMIE. An empirical method to correct the KAZR cloud top heights is described, and a merged radar dataset is produced to provide improved cloud boundary estimates, microphysics and radiative heating retrievals.

  6. Final Scientific/Technical Report Grant title: Use of ARM Measurements of Spectral Zenith Radiance for Better Understanding of 3D Cloud-Radiation Processes and Aerosol-Cloud Interaction This is a collaborative project with the NASA GSFC project of Dr. A. Marshak and W. Wiscombe (PIs). This report covers BU activities from February 2011 to June 2011 and BU "Â?no-cost extension" activities from June 2011 to June 2012. This report summarizes results that complement a final technical report submitted by the PIs in 2011.

    SciTech Connect (OSTI)

    Knyazikhin, Y

    2012-09-10T23:59:59.000Z

    Main results are summarized for work in these areas: spectrally-invariant approximation within atmospheric radiative transfer; spectral invariance of single scattering albedo for water droplets and ice crystals at weakly absorbing wavelengths; seasonal changes in leaf area of Amazon forests from leaf flushing and abscission; and Cloud droplet size and liquid water path retrievals from zenith radiance measurements.

  7. Broken and inhomogeneous cloud impact on satellite cloud particle effective radius and cloudphase retrievals

    E-Print Network [OSTI]

    Stoffelen, Ad

    on the particle size distribution, height, and thermo- dynamic phase of clouds. Water and ice clouds have parameterizations is the global dis- tribution of cloud thermodynamic phase, i.e., whether a cloud is composed on satellitederived cloud particle effective radius (re) and cloud phase (CPH) for broken and overcast inhomogeneous

  8. A Survey on Cloud Provider Security

    E-Print Network [OSTI]

    A Survey on Cloud Provider Security Measures Alex Pucher, Stratos Dimopoulos Abstract Cloud take advantage of this model already, but security and privacy concerns limit the further adoption agencies and start offering security certifications and separate tightly controlled "government" cloud

  9. Cicada: Predictive Guarantees for Cloud Network Bandwidth

    E-Print Network [OSTI]

    LaCurts, Katrina

    2014-03-24T23:59:59.000Z

    In cloud-computing systems, network-bandwidth guarantees have been shown to improve predictability of application performance and cost. Most previous work on cloud-bandwidth guarantees has assumed that cloud tenants know ...

  10. Electron-Cloud Build-Up: Summary

    E-Print Network [OSTI]

    Furman, M.A.

    2007-01-01T23:59:59.000Z

    Properties In?uencing Electron Cloud Phenomena,” Appl. Surf.Dissipation of the Electron Cloud,” Proc. PAC03 (Portland,is no signi?cant electron-cloud under nominal operating

  11. DIRSIG Cloud Modeling Capabilities; A Parametric Study

    E-Print Network [OSTI]

    Salvaggio, Carl

    1 DIRSIG Cloud Modeling Capabilities; A Parametric Study Kristen Powers powers:................................................................................................................... 13 Calculation of Sensor Reaching Radiance Truth Values for Cloudless & Stratus Cloud Scenes and Atmospheric Database Creation for Stratus Cloud Scene & Calculation of Associated Sensor Reaching Radiance

  12. Magellan: experiences from a Science Cloud

    E-Print Network [OSTI]

    Ramakrishnan, Lavanya

    2013-01-01T23:59:59.000Z

    2010. From Clusters To Clouds: xCAT 2 Is Out Of The Bag.Cost of Doing Science on the Cloud: The Montage Example. Incost of doing science on the cloud: the montage example. In

  13. The Cloud Computing and Other Variables

    E-Print Network [OSTI]

    Borjon-Kubota, Martha Estela

    2011-01-01T23:59:59.000Z

    12. Fragments in Six 13. Cloud Computing 14. Phase 15.Note 48. Devoured vi Cloud Computing and other Variables I.moment. Lasts hours. Cloud Computing Just there Over the

  14. The Magellan Final Report on Cloud Computing

    E-Print Network [OSTI]

    Coghlan, Susan

    2013-01-01T23:59:59.000Z

    4.3.1 Cloud Computing Attractive Features . 4.3.2A berkeley view of cloud computing. Technical Report UCB/matching computations on cloud computing platforms and hpc

  15. Tropical Cloud Properties and Radiative Heating Profiles

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Mather, James

    We have generated a suite of products that includes merged soundings, cloud microphysics, and radiative fluxes and heating profiles. The cloud microphysics is strongly based on the ARM Microbase value added product (Miller et al., 2003). We have made a few changes to the microbase parameterizations to address issues we observed in our initial analysis of the tropical data. The merged sounding product is not directly related to the product developed by ARM but is similar in that it uses the microwave radiometer to scale the radiosonde column water vapor. The radiative fluxes also differ from the ARM BBHRP (Broadband Heating Rate Profile) product in terms of the radiative transfer model and the sampling interval.

  16. Gamma-Ray Emission From Crushed Clouds in Supernova Remnants

    SciTech Connect (OSTI)

    Uchiyama, Yasunobu; Blandford, Roger D.; Funk, Stefan; /SLAC; Tajima, Hiroyasu; /Nagoya U., Solar-Terrestrial Environ. Lab.; Tanaka, Takaaki; /KIPAC, Menlo Park; ,

    2010-10-27T23:59:59.000Z

    It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of {pi}{sup 0}-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.

  17. Sunlight Changes Aerosols in Clouds | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sunlight Changes Aerosols in Clouds Sunlight Changes Aerosols in Clouds Released: October 20, 2011 Scientists show how sunlight alters optical, chemical properties of atmospheric...

  18. Study of Mechanisms of Aerosol Indirect Effects on Glaciated Clouds: Progress during the Project Final Technical Report

    SciTech Connect (OSTI)

    None

    2013-10-18T23:59:59.000Z

    This 3-year project has studied how aerosol pollution influences glaciated clouds. The tool applied has been an 'aerosol-cloud model'. It is a type of Cloud-System Resolving Model (CSRM) modified to include 2-moment bulk microphysics and 7 aerosol species, as described by Phillips et al. (2009, 2013). The study has been done by, first, improving the model and then performing sensitivity studies with validated simulations of a couple of observed cases from ARM. These are namely the Tropical Warm Pool International Cloud Experiment (TWP-ICE) over the tropical west Pacific and the Cloud and Land Surface Interaction Campaign (CLASIC) over Oklahoma. During the project, sensitivity tests with the model showed that in continental clouds, extra liquid aerosols (soluble aerosol material) from pollution inhibited warm rain processes for precipitation production. This promoted homogeneous freezing of cloud droplets and aerosols. Mass and number concentrations of cloud-ice particles were boosted. The mean sizes of cloud-ice particles were reduced by the pollution. Hence, the lifetime of glaciated clouds, especially ice-only clouds, was augmented due to inhibition of sedimentation and ice-ice aggregation. Latent heat released from extra homogeneous freezing invigorated convective updrafts, and raised their maximum cloud-tops, when aerosol pollution was included. In the particular cases simulated in the project, the aerosol indirect effect of glaciated clouds was twice than of (warm) water clouds. This was because glaciated clouds are higher in the troposphere than water clouds and have the first interaction with incoming solar radiation. Ice-only clouds caused solar cooling by becoming more extensive as a result of aerosol pollution. This 'lifetime indirect effect' of ice-only clouds was due to higher numbers of homogeneously nucleated ice crystals causing a reduction in their mean size, slowing the ice-crystal process of snow production and slowing sedimentation. In addition to the known indirect effects (glaciation, riming and thermodynamic), new indirect effects were discovered and quantified due to responses of sedimentation, aggregation and coalescence in glaciated clouds to changing aerosol conditions. In summary, the change in horizontal extent of the glaciated clouds ('lifetime indirect effects'), especially of ice-only clouds, was seen to be of higher importance in regulating aerosol indirect effects than changes in cloud properties ('cloud albedo indirect effects').

  19. 3, 44614488, 2003 Cloud particle

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    effects. On one hand, clouds reflect the incoming solar radiation and thus cool the Earth significant effect on the radiation balance (Wielicki et al, 1996; Mitchell, 1989) due to two competing-Atmosphere system. On the other hand, clouds absorb longwave thermal radiation coming from the surface and then re

  20. EVOLUTIONARY COMPUTATION AND POST-WILDFIRE LAND-COVER MAPPING WITH MULTISPECTRAL IMAGERY.

    SciTech Connect (OSTI)

    Brumby, Steven P.; Koch, S. W. (Steven W.); Hansen, L. A. (Leslie A.)

    2001-01-01T23:59:59.000Z

    The Cerro Grande Los Alamos wildfire devastated approximately 43,000 acres (17,500 ha) of forested land, and destroyed over 200 structures in the town of Los Alamos. The need to monitor the continuing impact of the fire on the local environment has led to the application of a number of advanced remote sensing technologies. During and after the fire, remote-sensing data was acquired fiorn a variety of aircraft- and satellite-based sensors, including Landsat 7 Enhanced Thematic Mapper (ETM+). We now report on the application of a machine learning technique io the automated classification of land cover using multispectral imagery. We apply a hybrid gertelic programminghupervised classification technique to evolve automatic feature extraction algorithms. We use a software package we have developed at Los Alamos National Laboratory, called GENIE, to carry out this evolution. We use multispectral imagery fiom the Landsat 7 ETM+ instrument fiom before and after the wildfire. Using an existing land cover classification based on a Landsat 5 TM scene for our training data, we evolve algorithms that distinguish a range of land cover categories, along with clouds and cloud shadows. The details of our evolved classification are compared to the manually produced land-cover classification. Keywords: Feature Extraction, Genetic programming, Supervised classification, Multi-spectral imagery, Land cover, Wildfire.

  1. Retrievals of mixed-phase cloud properties during the National Polar-Orbiting Operational Environmental

    E-Print Network [OSTI]

    Liou, K. N.

    Retrievals of mixed-phase cloud properties during the National Polar-Orbiting Operational/Visible Infrared Imaging Radiometer Suite (VIIRS) to retrieve pixel-level mixed-phase cloud optical thicknesses Satellite Observations Validation Project (C3VP), were analyzed. The performance of the mixed-phase

  2. MODELLING RADIATIVELY ACTIVE WATER-ICE CLOUDS: IMPACT ON THE THERMAL STRUCTURE AND WATER CYCLE.

    E-Print Network [OSTI]

    Madeleine, Jean-Baptiste

    MODELLING RADIATIVELY ACTIVE WATER-ICE CLOUDS: IMPACT ON THE THERMAL STRUCTURE AND WATER CYCLE. J. The essential role of water-ice clouds in shaping the thermal structure of the martian atmosphere has been long presumed [1] but neglected in GCMs because of the lack of observations and difficulty to predict

  3. OBSERVATIONS OF TWO TRANSIENT LUMINOUS EVENT-

    E-Print Network [OSTI]

    Rutledge, Steven

    OBSERVATIONS OF TWO TRANSIENT LUMINOUS EVENT- PRODUCING MESOSCALE CONVECTIVE SYSTEMS Timothy LangC by positive cloud-to-ground (+CG) lightning can lead to transient luminous events (TLEs; Williams 1998; Lyons

  4. A SEARCH FOR DUST EMISSION IN THE LEO INTERGALACTIC CLOUD

    SciTech Connect (OSTI)

    Bot, Caroline; Helou, George; Puget, Jeremie [California Institute of Technology, Pasadena, CA 91125 (United States); Latter, William B. [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Schneider, Stephen [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Terzian, Yervant [Department of Astronomy/NAIC, Cornell University, Ithaca, NY 14853 (United States)], E-mail: bot@astro.u-strasbg.fr

    2009-08-15T23:59:59.000Z

    We present a search for infrared dust emission associated with the Leo cloud, a large intergalactic cloud in the M96 group. Mid-infrared and far-infrared images were obtained with the InfraRed Array Camera and the Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope. Our analysis of these maps is done at each wavelength relative to the H I spatial distribution. We observe a probable detection at 8 {mu}m and a marginal detection at 24 {mu}m associated with the highest H I column densities in the cloud. At 70 and 160 {mu}m, upper limits on the dust emission are deduced. The level of the detection is low so that the possibility of a fortuitous cirrus clump or of an overdensity of extragalactic sources along the line of sight cannot be excluded. If this detection is confirmed, the quantities of dust inferred imply a dust-to-gas ratio in the intergalactic cloud up to a few times solar but no less than 1/20 solar. A confirmed detection would therefore exclude the possibility that the intergalactic cloud has a primordial origin. Instead, this large intergalactic cloud could therefore have been formed through interactions between galaxies in the group.

  5. Electron cloud experiments at Fermilab: Formation and mitigation

    SciTech Connect (OSTI)

    Zwaska, R.; /Fermilab

    2011-06-01T23:59:59.000Z

    We have performed a series of experiments at Fermilab to explore the electron cloud phenomenon. The Main Injector will have its beam intensity increased four-fold in the Project X upgrade, and would be subject to instabilities from the electron cloud. We present measurements of the cloud formation in the Main Injector and experiments with materials for the mitigation of the Cloud. An experimental installation of Titanium-Nitride (TiN) coated beam pipes has been under study in the Main Injector since 2009; this material was directly compared to an adjacent stainless chamber through electron cloud measurement with Retarding Field Analyzers (RFAs). Over the long period of running we were able to observe the secondary electron yield (SEY) change and correlate it with electron fluence, establishing a conditioning history. Additionally, the installation has allowed measurement of the electron energy spectrum, comparison of instrumentation techniques, and energydependent behavior of the electron cloud. Finally, a new installation, developed in conjunction with Cornell and SLAC, will allow direct SEY measurement of material samples irradiated in the accelerator.

  6. Cloud structure and composition of Jupiter's troposphere from 5-{\\mu}m Cassini VIMS spectroscopy

    E-Print Network [OSTI]

    Giles, Rohini S; Irwin, Patrick G J

    2015-01-01T23:59:59.000Z

    Jupiter's tropospheric composition and cloud structure are studied using Cassini VIMS 4.5-5.1 {\\mu}m thermal emission spectra from the 2000-2001 flyby. We make use of both nadir and limb darkening observations on the planet's nightside, and compare these with dayside observations. Although there is significant spatial variability in the 5-{\\mu}m brightness temperatures, the shape of the spectra remain very similar across the planet, suggesting the presence of a spectrally-flat, spatially inhomogeneous cloud deck. We find that a simple cloud model consisting of a single, compact cloud is able to reproduce both nightside and dayside spectra, subject to the following constraints: (i) the cloud base is located at pressures of 1.2 bar or lower; (ii) the cloud particles are highly scattering; (iii) the cloud is sufficiently spectrally flat. Using this cloud model, we search for global variability in the cloud opacity and the phosphine deep volume mixing ratio. We find that the vast majority of the 5-{\\mu}m inhomoge...

  7. X-Ray Binary Systems in the Small Magellanic Cloud

    E-Print Network [OSTI]

    P. Kahabka; W. Pietsch

    1997-06-09T23:59:59.000Z

    We present the result of a systematic search for spectrally hard and soft X-ray binary systems in the Small Magellanic Cloud (SMC). This search has been applied to ROSAT PSPC data (0.1-2.4 keV) collected during 9 pointed observations towards this galaxy covering a time span of 2 years from October 91 till October 93. Selection criteria have been defined in order to confine the sample of candidates. Finally 7 spectrally hard and 4 spectrally soft sources were selected from the list as candidates for binaries in the SMC. The sample is luminosity limited (>3.10**35 erg/s). SMC X-1 has been observed during a full binary orbit starting with a low-state covering an X-ray eclipse and emerging into a bright long-duration flare with two short-duration flares separated by 10 hours. The Be type transient SMC X-2 has been redetected with ROSAT. Variability has been found in the sources RX J0051.8-7231 and RX J0052.1-731 already discovered with Einstein. RX J0101.0-7206 has been discovered at the north-eastern boundary of the giant SMC HII region N66 during an X-ray outburst and half a year later during a quiescent phase. A variable source, RX J0049.1-7250, located north-east of the SMC supernova remnant N19 and which may either be an X-ray binary or an AGN turns out to be strongly absorbed. It may be located behind the SMC. If it is an X-ray binary then it radiates at the Eddington limit in the X-ray bright state. Another variable and hard X-ray source RX J0032.9-7348 has been discovered at the south-eastern border of the body of the SMC. A high mass X-ray binary nature is favored for this source. We searched for CAL87 like systems in the SMC catalog and found none. A new candidate supersoft source RX J0103.8-7254 has been detected. We cannot exclude that it is a foreground object.

  8. Using cloud resolving model simulations of deep convection to inform cloud parameterizations in large-scale models

    SciTech Connect (OSTI)

    Klein, Stephen A.; Pincus, Robert; Xu, Kuan-man

    2003-06-23T23:59:59.000Z

    Cloud parameterizations in large-scale models struggle to address the significant non-linear effects of radiation and precipitation that arise from horizontal inhomogeneity in cloud properties at scales smaller than the grid box size of the large-scale models. Statistical cloud schemes provide an attractive framework to self-consistently predict the horizontal inhomogeneity in radiation and microphysics because the probability distribution function (PDF) of total water contained in the scheme can be used to calculate these non-linear effects. Statistical cloud schemes were originally developed for boundary layer studies so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known about how deep convection alters the PDF of total water or how to parameterize these impacts. These issues are explored with data from a 29 day simulation by a cloud resolving model (CRM) of the July 1997 ARM Intensive Observing Period at the Southern Great Plains site. The simulation is used to answer two questions: (a) how well can the beta distribution represent the PDFs of total water relative to saturation resolved by the CRM? (b) how can the effects of convection on the PDF be parameterized? In addition to answering these questions, additional sections more fully describe the proposed statistical cloud scheme and the CRM simulation and analysis methods.

  9. THE MAGELLANIC INTER-CLOUD PROJECT (MAGIC). I. EVIDENCE FOR INTERMEDIATE-AGE STELLAR POPULATIONS IN BETWEEN THE MAGELLANIC CLOUDS

    SciTech Connect (OSTI)

    Noeel, N. E. D.; Read, J. I. [ETH Zuerich, Institute for Astronomy, Wolfgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); Conn, B. C.; Rix, H.-W. [Max Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Carrera, R. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain); Dolphin, A., E-mail: noelia@phys.ethz.ch [Raytheon Company, P.O. Box 11337, Tucson, AZ 85734-1337 (United States)

    2013-05-10T23:59:59.000Z

    The origin of the gas in between the Magellanic Clouds (MCs)-known as the ''Magellanic Bridge'' (MB)-is puzzling. Numerical simulations suggest that the MB formed from tidally stripped gas and stars in a recent interaction between the MCs. However, the apparent lack of stripped intermediate- or old-age stars associated with the MB is at odds with this picture. In this paper, we present the first results from the MAGellanic Inter-Cloud program (MAGIC) aimed at probing the stellar populations in the inter-Cloud region. We present observations of the stellar populations in two large fields located in between the Large and Small Magellanic Clouds (LMC/SMC), secured using the WFI camera on the 2.2 m telescope in La Silla. Using a synthetic color-magnitude diagram technique, we present the first quantitative evidence for the presence of intermediate-age and old stars in the inter-Cloud region. The intermediate-age stars-which make up {approx}28% of all stars in the region-are not present in fields at a similar distance from the SMC in a direction pointing away from the LMC. This provides potential evidence that these intermediate-age stars could have been tidally stripped from the SMC. However, spectroscopic studies will be needed to confirm or rule out the tidal origin for the inter-Cloud gas and stars.

  10. The dynamics and high-energy emission of conductive gas clouds in supernova-driven galactic superwinds

    E-Print Network [OSTI]

    A. Marcolini; D. K. Strickland; A. D'Ercole; T. M. Heckman; C. G. Hoopes

    2005-06-27T23:59:59.000Z

    In this paper we present high-resolution hydrodynamical models of warm ionized clouds embedded in a superwind, and compare the OVI and soft X-ray properties to the existing observational data. These models include thermal conduction, which we show plays an important role in shaping both the dynamics and radiative properties of the resulting wind/cloud interaction. Heat conduction stabilizes the cloud by inhibiting the growth of K-H and R-T instabilities, and also generates a shock wave at the cloud's surface that compresses the cloud. This dynamical behaviour influences the observable properties. We find that while OVI emission and absorption always arises in cloud material at the periphery of the cloud, most of the soft X-ray arises in the region between the wind bow shock and the cloud surface, and probes either wind or cloud material depending on the strength of conduction and the relative abundances of the wind with respect to the cloud. In general only a small fraction (thermal conduction, in particular in terms of the OVI-to-X-ray luminosity ratio, but cloud life times are uncomfortably short (thermal conductivity and found that even when we reduced conduction by a factor of 25 that the simulations retained the beneficial hydrodynamical stability and low O{\\sc vi}-to-X-ray luminosity ratio found in the Spitzer-level conductive models, while also having reduced evaporation rates.

  11. Evaluating cloud retrieval algorithms with the ARM BBHRP framework

    SciTech Connect (OSTI)

    Mlawer,E.; Dunn,M.; Mlawer, E.; Shippert, T.; Troyan, D.; Johnson, K. L.; Miller, M. A.; Delamere, J.; Turner, D. D.; Jensen, M. P.; Flynn, C.; Shupe, M.; Comstock, J.; Long, C. N.; Clough, S. T.; Sivaraman, C.; Khaiyer, M.; Xie, S.; Rutan, D.; Minnis, P.

    2008-03-10T23:59:59.000Z

    Climate and weather prediction models require accurate calculations of vertical profiles of radiative heating. Although heating rate calculations cannot be directly validated due to the lack of corresponding observations, surface and top-of-atmosphere measurements can indirectly establish the quality of computed heating rates through validation of the calculated irradiances at the atmospheric boundaries. The ARM Broadband Heating Rate Profile (BBHRP) project, a collaboration of all the working groups in the program, was designed with these heating rate validations as a key objective. Given the large dependence of radiative heating rates on cloud properties, a critical component of BBHRP radiative closure analyses has been the evaluation of cloud microphysical retrieval algorithms. This evaluation is an important step in establishing the necessary confidence in the continuous profiles of computed radiative heating rates produced by BBHRP at the ARM Climate Research Facility (ACRF) sites that are needed for modeling studies. This poster details the continued effort to evaluate cloud property retrieval algorithms within the BBHRP framework, a key focus of the project this year. A requirement for the computation of accurate heating rate profiles is a robust cloud microphysical product that captures the occurrence, height, and phase of clouds above each ACRF site. Various approaches to retrieve the microphysical properties of liquid, ice, and mixed-phase clouds have been processed in BBHRP for the ACRF Southern Great Plains (SGP) and the North Slope of Alaska (NSA) sites. These retrieval methods span a range of assumptions concerning the parameterization of cloud location, particle density, size, shape, and involve different measurement sources. We will present the radiative closure results from several different retrieval approaches for the SGP site, including those from Microbase, the current 'reference' retrieval approach in BBHRP. At the NSA, mixed-phase clouds and cloud with a low optical depth are prevalent; the radiative closure studies using Microbase demonstrated significant residuals. As an alternative to Microbase at NSA, the Shupe-Turner cloud property retrieval algorithm, aimed at improving the partitioning of cloud phase and incorporating more constrained, conditional microphysics retrievals, also has been evaluated using the BBHRP data set.

  12. Cloud Occurrence Frequency at the Barrow, Alaska, ARM Climate Research Facility for 2008 Third Quarter 2009 ARM and Climate Change Prediction Program Metric Report

    SciTech Connect (OSTI)

    M Jensen; K Johnson; JH Mather

    2009-07-14T23:59:59.000Z

    Clouds represent a critical component of the Earth’s atmospheric energy balance as a result of their interactions with solar and terrestrial radiation and a redistribution of heat through convective processes and latent heating. Despite their importance, clouds and the processes that control their development, evolution and lifecycle remain poorly understood. Consequently, the simulation of clouds and their associated feedbacks is a primary source of inter-model differences in equilibrium climate sensitivity. An important step in improving the representation of cloud process simulations is an improved high-resolution observational data set of the cloud systems including their time evolution. The first order quantity needed to understand the important role of clouds is the height of cloud occurrence and how it changes as a function of time. To this end, the Atmospheric Radiation Measurement (ARM) Climate Research Facilities (ACRF) suite of instrumentation has been developed to make the observations required to improve the representation of cloud systems in atmospheric models.

  13. Convective plumes and the scarcity of Titan's clouds Ralph D. Lorenz,1

    E-Print Network [OSTI]

    Lorenz, Ralph D.

    dynamical models and with the relative tropospheric cloud cover, which is only $1% on Titan. Rainstorms is significantly opaque to thermal infrared radiation, leading to a strong greenhouse effect. The equivalent grey is absorbed by methane in the troposphere. Only around 10% of the incident solar radiation reaches the surface

  14. Autonomous observing strategies for the ocean carbon cycle

    SciTech Connect (OSTI)

    Bishop, James K.; Davis, Russ E.

    2000-07-26T23:59:59.000Z

    Understanding the exchanges of carbon between the atmosphere and ocean and the fate of carbon delivered to the deep sea is fundamental to the evaluation of ocean carbon sequestration options. An additional key requirement is that sequestration must be verifiable and that environmental effects be monitored and minimized. These needs can be addressed by carbon system observations made from low-cost autonomous ocean-profiling floats and gliders. We have developed a prototype ocean carbon system profiler based on the Sounding Oceanographic Lagrangian Observer (SOLO; Davis et al., 1999). The SOLO/ carbon profiler will measure the two biomass components of the carbon system and their relationship to physical variables, such as upper ocean stratification and mixing. The autonomous observations within the upper 1500 m will be made on daily time scales for periods of months to seasons and will be carried out in biologically dynamic locations in the world's oceans that are difficult to access with ships (due to weather) or observe using remote sensing satellites (due to cloud cover). Such an observational capability not only will serve an important role in carbon sequestration research but will provide key observations of the global ocean's natural carbon cycle.

  15. Constraints on the Cosmic Rays in the Small Magellanic Cloud

    E-Print Network [OSTI]

    Arnon Dar; Ari Laor; Abraham Loeb

    1993-02-25T23:59:59.000Z

    We show that recent $\\gamma$-ray observations of the Small Magellanic Cloud with EGRET rule out a universal cosmic ray flux only at energies below $\\approx 10$ GeV, while the observed diffuse X-ray and $\\gamma$-ray background radiations have already ruled out, by more than three orders of magnitude, a universal extragalactic cosmic ray flux identical to that observed in the local solar neighborhood at energies below $10^6$ GeV.

  16. Construction Costs of Six Landfill Cover Designs

    SciTech Connect (OSTI)

    Dwyer, S.F.

    1998-12-23T23:59:59.000Z

    A large-scale field demonstration comparing and contrasting final landfill cover designs has been constructed and is currently being monitored. Four alternative cover designs and two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side for direct comparison. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper provides an overview of the construction costs of each cover design.

  17. Cost comparisons of alternative landfill final covers

    SciTech Connect (OSTI)

    Dwyer, S.F.

    1997-02-01T23:59:59.000Z

    A large-scale field demonstration comparing and contrasting final landfill cover designs has been constructed and is currently being monitored. Four alternative cover designs and two conventional designs (a RCRA Subtitle ``D`` Soil Cover and a RCRA Subtitle ``C`` Compacted Clay Cover) were constructed of uniform size, side-by-side. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper provides an overview of the construction costs of each cover design.

  18. Platform for Hybrid Cloud Technical White Paper

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Platform for Hybrid Cloud Technical White Paper Published: September 2013 (updated) Applies to: SQL Server and Windows Azure Summary: Cloud computing brings a new paradigm shift in computing in the cloud with greater scale and flexibility. Microsoft SQL Server runs very well in the cloud environment

  19. Cloud Computing An enterprise perspective Raghavan Subramanian

    E-Print Network [OSTI]

    Rajamani, Sriram K.

    Cloud Computing ­ An enterprise perspective Raghavan Subramanian Infosys Technologies Limited #12;2Infosys Confidential Overview of cloud computing? Cloud computing* Computing in which dynamically scalable of cloud computing 1. On-demand self-service 2. Ubiquitous network access 3. Location independent resource

  20. IBM Software Solution Brief Safeguarding the cloud

    E-Print Network [OSTI]

    IBM Software Solution Brief Safeguarding the cloud with IBM Security solutions Maintain visibility and control with proven security solutions for public, private and hybrid clouds Highlights Address cloud internal and external users, data, applications and workloads as they move to and from the cloud Regain

  1. Draft NISTIR 80061 NIST Cloud Computing2

    E-Print Network [OSTI]

    Draft NISTIR 80061 NIST Cloud Computing2 Forensic Science Challenges NIST Cloud Computing Forensic Computing11 Forensic Science Challenges 12 NIST Cloud Computing Forensic Science Working Group13 Information challenges77 faced by experts when responding to incidents that have occurred in a cloud-computing ecosystem

  2. Cloud Data Management (CDM) Yunpeng Chai

    E-Print Network [OSTI]

    /W performance / Parallelism No/ Simple SQL operations 12 /26 Survey of CDM Cloud Storage: Architecture: Master#12;Cloud Data Management (CDM) Yunpeng Chai 2 /26 Outline Motivation of CDM Survey of CDM IBM SUR Cloud China Mobile National Health Care #12;9 /26 Outline Motivation of CDM Survey of CDM IBM SUR Cloud

  3. 6, 43414373, 2006 Cloud-borne aerosol

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Discussions Impact of cloud-borne aerosol representation on aerosol direct and indirect effects S. J. Ghan of aerosols employ a variety of rep- resentations of such cloud-borne particles. Here we use a global aerosol- ulated aerosol, cloud and radiation fields to various approximations to the representa- tion of cloud

  4. Vision: Cloud-Powered Sight for All Showing the Cloud What You See

    E-Print Network [OSTI]

    Zhong, Lin

    Vision: Cloud-Powered Sight for All Showing the Cloud What You See Paramvir Bahl Matthai Philipose argue that for computers to do more for us, we need to show the cloud what we see and embrace cloud General Terms Algorithms, Design, Human Factors, Languages, Performance, Security Keywords Camera, cloud

  5. Cloud Futures Workshop 2010 Cloud Computing Support for Massively Social Gaming Alexandru Iosup

    E-Print Network [OSTI]

    Iosup, Alexandru

    1 Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming Alexandru Iosup Pierre (Vrije U.). Cloud Computing Support for Massively Social Gaming (Rain for the Thirsty) #12;Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming 2 Intermezzo: Tips on how

  6. Constraints on Stirring and Dissipation of MHD Turbulence in Molecular Clouds

    E-Print Network [OSTI]

    Shantanu Basu; Chigurupati Murali

    2001-02-23T23:59:59.000Z

    We discuss constraints on the rates of stirring and dissipation of MHD turbulence in molecular clouds. Recent MHD simulations suggest that turbulence in clouds decays rapidly, thus providing a significant source of energy input, particularly if driven at small scales by, for example, bipolar outflows. We quantify the heating rates by combining the linewidth-size relations, which describe global cloud properties, with numerically determined dissipation rates. We argue that, if cloud turbulence is driven on small internal scales, the $^{12}$CO flux (enhanced by emission from weakly supersonic shocks) will be much larger than observed; this, in turn, would imply excitation temperatures significantly above observed values. We reach two conclusions: (1) small-scale driving by bipolar outflows cannot possibly account for cloud support and yield long-lived clouds, unless the published MHD dissipation rates are seriously overestimated; (2) driving on large scales (comparable to the cloud size) is much more viable from an energetic standpoint, and if the actual net dissipation rate is only slightly lower than what current MHD simulations estimate, then the observationally inferred lifetimes and apparent virial equilibrium of molecular clouds can be explained.

  7. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    ScienceCinema (OSTI)

    Norris, Joe [Scripps Institution of Oceanography, University of California, San Diego, California, USA

    2010-09-01T23:59:59.000Z

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  8. Resolved Atomic Super-clouds in Spiral Galaxies

    E-Print Network [OSTI]

    Robert Braun

    1995-12-13T23:59:59.000Z

    High quality data are presented of neutral hydrogen emission and absorption in the fields of eleven of the nearest spiral galaxies. Multi-configuration VLA observations have provided angular resolution of 6~arcsec (corresponding to about 100~pc at the average galaxy distance of 3.5~Mpc) and velocity resolution of 6~km~s$^{-1}$, while accurately recovering the total line flux detected previously with filled apertures. Previous experience suggests that this physical resolution is sufficient to at least marginally resolve the \\ion{H}{1} super-cloud population which delineates regions of active star formation. A high brightness filamentary network of \\ion{H}{1} super-clouds is seen in each galaxy. Emission brightness temperatures in excess of 200~Kelvin are sometimes detected at large radii, even in relatively face-on systems. All galaxies display a systematic increase in the observed brightness temperature of super-clouds with radius, followed by a flattening and subsequent decline. In the few instances where background continuum sources allow detection of \\ion{H}{1} absorption, the indicative spin temperatures are consistent with the super-cloud brightness temperature seen in emission at similar radii. These data suggest substantial opacity of the \\ion{H}{1} in the super-cloud network.

  9. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    SciTech Connect (OSTI)

    Norris, Joel (Scripps Institution of Oceanography, UC San Diego) [Scripps Institution of Oceanography, UC San Diego

    2010-05-10T23:59:59.000Z

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  10. Mixed phase clouds, cloud electrification and remote sensing.

    SciTech Connect (OSTI)

    Chylek, P. (Petr); Borel, C. C. (Christoph C.); Klett, James

    2004-01-01T23:59:59.000Z

    Most of hypothesis trying to explain charge separation in thunderstorm clouds require presence of ice and supercooled water. Thus the existence of ice or at least mixed phase regions near cloud tops should be a necessary (but not a sufficient) condition for development of lightning. We show that multispectral satellite based instruments, like the DOE MTI (Multispectral Thermal Imager) or NASA MODIS (Moderate Resolution Imaging Spectroradiometer), using the near infrared and visible spectral bands are able to distinguish between water, ice and mixed phase cloud regions. An analysis of the MTI images of mixed phase clouds - with spatial resolution of about 20 m - shows regions of pure water, pure ice as well as regions of water/ice mixtures. We suggest that multispectral satellite instruments may be useful for a short time forecast of lightning probabilities.

  11. Estimation of precipitable water from surface observations

    E-Print Network [OSTI]

    Kahan, Archie Marion

    1959-01-01T23:59:59.000Z

    for estimating the precipitable water at Lake Charles, Louisiana. P red ic tors employed were surface vapor p re s ? sure, ceiling, cloud cover , cloud type, wind, pressure change and iv season. E rrors of estimate averaged approximately one tenth o f... of the photocells and the intense radiation of the noon sun leads one to accept the reality of a ce ll temperature greater than the ambient air temperature. The ce lls are, in effect, miniature green ? houses, The epoxy resin cylinder encasing the crysta l...

  12. Covered Product Category: Uninterruptible Power Supplies (for...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Applications) Covered Product Category: Uninterruptible Power Supplies (for Data Center, Computer, and Telecommunication Applications) The Federal Energy Management...

  13. A Comparison of Multiscale Variations of Decade-long Cloud Fractions from Six Different Platforms over the Southern Great Plains in the United States

    SciTech Connect (OSTI)

    Wu, Wei; Liu, Yangang; Jensen, Michael; Toto, Tami; Foster, Michael J.; Long, Charles N.

    2014-03-27T23:59:59.000Z

    This study investigates 1997-2011 observationally based cloud fraction estimates from different platforms over the Southern Great Plains, United States, including three ground-based estimates and three satellite-based estimates at multiple temporal and spatial scales. They are: 1) the Active Remotely Sensed Clouds Locations (ARSCL); 2) the Total Sky Imager (TSI); 3) the Radiative Flux Analysis (RFA); 4) Geostationary Operational Environmental Satellite (GOES); 5) the International Satellite Cloud Climatology Project (ISCCP); and 6) Advanced Very High Resolution Radiometer Pathfinder Atmospheres Extended (PATMOS-x). A substantial disagreement is evident among different estimates, especially for ISCCP and ARSCL with statistically significant larger cloud fractions than the other estimates. For example, ISCCP and ARSCL mean cloud fractions in January are ~21% and 8% larger than the average from all the other estimates, respectively. Three estimates (ISCCP, ARSCL, GOES) exhibit an 8%-10% overall increase in the annually averaged cloud fractions from 1998 to 2009; the other three estimates (TSI, RFA, and PATMOS-x) exhibit no significant tendency of increase in this decade. Monthly cloud fractions from all the estimates exhibit Gaussian-like distributions while the distributions of daily cloud fractions are dependent on spatial scales. Investigations of high-resolution cloud fractions reveal that the differences stem from the inconsistent definitions of cloud fraction. Findings from this study suggest caution when using observationally based cloud fraction estimates for climate studies, highlighting that the consistency in defining cloud fraction between models and observations is crucial for studying the Earth’s climate.

  14. ANISOTROPY LENGTHENS THE DECAY TIME OF TURBULENCE IN MOLECULAR CLOUDS

    SciTech Connect (OSTI)

    Hansen, Charles E.; McKee, Christopher F.; Klein, Richard I. [Astronomy Department, University of California, Berkeley, CA 94720 (United States)

    2011-09-01T23:59:59.000Z

    The decay of isothermal turbulence with velocity anisotropy is investigated using computational simulations and synthetic observations. We decompose the turbulence into isotropic and anisotropic components with total velocity dispersions {sigma}{sub iso} and {sigma}{sub ani}, respectively. We find that the decay rate of the turbulence depends on the crossing time of the isotropic component only. A cloud of size L with significant anisotropy in its turbulence has a dissipation time, t{sub diss} = L/(2{sigma}{sub iso}). This translates into turbulent energy decay rates on the cloud scale that can be much lower for anisotropic turbulence than for isotropic turbulence. To help future observations determine whether observed molecular clouds have the level of anisotropy required to maintain the observed level of turbulence over their lifetimes, we performed a principal component analysis on our simulated clouds. Even with projection effects washing out the anisotropic signal, there is a measurable difference in the axis-constrained principal component analysis performed in directions parallel and perpendicular to the direction of maximum velocity dispersion. When this relative difference, {psi}, is 0.1, there is enough anisotropy for the dissipation time to triple the expected isotropic value. We provide a fit for converting {psi} into an estimate for the dissipation time, t{sub diss}.

  15. Cloud vertical distribution from radiosonde, remote sensing, and model simulations

    E-Print Network [OSTI]

    Li, Zhanqing

    Cloud vertical distribution from radiosonde, remote sensing, and model simulations Jinqiang Zhang's radiation budget and atmospheric adiabatic heating. Yet it is among the most difficult quantities to observe Great Plains and along with ground- based and space-borne remote sensing products, use it to evaluate

  16. Study of Multi-Scale Cloud Processes Over the Tropical Western Pacific Using Cloud-Resolving Models Constrained by Satellite Data

    SciTech Connect (OSTI)

    Dudhia, Jimy

    2013-03-12T23:59:59.000Z

    Clouds in the tropical western Pacific are an integral part of the large scale environment. An improved understanding of the multi-scale structure of clouds and their interactions with the environment is critical to the ARM (Atmospheric Radiation Measurement) program for developing and evaluating cloud parameterizations, understanding the consequences of model biases, and providing a context for interpreting the observational data collected over the ARM Tropical Western Pacific (TWP) sites. Three-dimensional cloud resolving models (CRMs) are powerful tools for developing and evaluating cloud parameterizations. However, a significant challenge in using CRMs in the TWP is that the region lacks conventional data, so large uncertainty exists in defining the large-scale environment for clouds. This project links several aspects of the ARM program, from measurements to providing improved analyses, and from cloud-resolving modeling to climate-scale modeling and parameterization development, with the overall objective to improve the representations of clouds in climate models and to simulate and quantify resolved cloud effects on the large-scale environment. Our objectives will be achieved through a series of tasks focusing on the use of the Weather Research and Forecasting (WRF) model and ARM data. Our approach includes: -- Perform assimilation of COSMIC GPS radio occultation and other satellites products using the WRF Ensemble Kalman Filter assimilation system to represent the tropical large-scale environment at 36 km grid resolution. This high-resolution analysis can be used by the community to derive forcing products for single-column models or cloud-resolving models. -- Perform cloud-resolving simulations using WRF and its nesting capabilities, driven by the improved regional analysis and evaluate the simulations against ARM datasets such as from TWP-ICE to optimize the microphysics parameters for this region. A cirrus study (Mace and co-authors) already exists for TWP-ICE using satellite and ground-based observations. -- Perform numerical experiments using WRF to investigate how convection over tropical islands in the Maritime Continent interacts with large-scale circulation and affects convection in nearby regions. -- Evaluate and apply WRF as a testbed for GCM cloud parameterizations, utilizing the ability of WRF to run on multiple scales (from cloud resolving to global) to isolate resolution and physics issues from dynamical and model framework issues. Key products will be disseminated to the ARM and larger community through distribution of data archives, including model outputs from the data assimilation products and cloud resolving simulations, and publications.

  17. Parameterizations of Cloud Microphysics and Indirect Aerosol Effects

    SciTech Connect (OSTI)

    Tao, Wei-Kuo [NASA/GSFC] [NASA/GSFC

    2014-05-19T23:59:59.000Z

    1. OVERVIEW Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 2001]. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds [NRC, 2001]." The aerosol effect on clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path [Twomey, 1977] and the "semi-direct" effect on cloud coverage [e.g., Ackerman et al., 2000]. Enhanced aerosol concentrations can also suppress warm rain processes by producing a narrow droplet spectrum that inhibits collision and coalescence processes [e.g., Squires and Twomey, 1961; Warner and Twomey, 1967; Warner, 1968; Rosenfeld, 1999]. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect [Albrecht, 1989], is even more complex, especially for mixed-phase convective clouds. Table 1 summarizes the key observational studies identifying the microphysical properties, cloud characteristics, thermodynamics and dynamics associated with cloud systems from high-aerosol continental environments. For example, atmospheric aerosol concentrations can influence cloud droplet size distributions, warm-rain process, cold-rain process, cloud-top height, the depth of the mixed phase region, and occurrence of lightning. In addition, high aerosol concentrations in urban environments could affect precipitation variability by providing an enhanced source of cloud condensation nuclei (CCN). Hypotheses have been developed to explain the effect of urban regions on convection and precipitation [van den Heever and Cotton, 2007 and Shepherd, 2005]. Recently, a detailed spectral-bin microphysical scheme was implemented into the Goddard Cumulus Ensemble (GCE) model. Atmospheric aerosols are also described using number density size-distribution functions. A spectral-bin microphysical model is very expensive from a computational point of view and has only been implemented into the 2D version of the GCE at the present time. The model is tested by studying the evolution of deep tropical clouds in the west Pacific warm pool region and summertime convection over a mid-latitude continent with different concentrations of CCN: a low "clean" concentration and a high "dirty" concentration. The impact of atmospheric aerosol concentration on cloud and precipitation will be investigated. 2. MODEL DESCRIPTION AND CASE STUDIES 2.1 GCE MODEL The model used in this study is the 2D version of the GCE model. Modeled flow is anelastic. Second- or higher-order advection schemes can produce negative values in the solution. Thus, a Multi-dimensional Positive Definite Advection Transport Algorithm (MPDATA) has been implemented into the model. All scalar variables (potential temperature, water vapor, turbulent coefficient and all five hydrometeor classes) use forward time differencing and the MPDATA for advection. Dynamic variables, u, v and w, use a second-order accurate advection scheme and a leapfrog time integration (kinetic energy semi-conserving method). Short-wave (solar) and long-wave radiation as well as a subgrid-scale TKE turbulence scheme are also included in the model. Details of the model can be found in Tao and Simpson (1993) and Tao et al. (2003). 2.2 Microphysics (Bin Model) The formulation of the explicit spectral-bin microphysical processes is based on solving stochastic kinetic equations for the size distribution functions of water droplets (cloud droplets and raindrops), and six types of ice particles: pristine ice crystals (columnar and plate-like), snow (dendrites and aggregates), graupel and frozen drops/hail. Each type is described by a special size distribution function containing 33 categories (bin

  18. Environmental control of cloud-to-ground lightning polarity in severe storms

    E-Print Network [OSTI]

    Buffalo, Kurt Matthew

    2009-05-15T23:59:59.000Z

    directly control cloud electrification and CG flash polarity. A more specific hypothesis, which has been supported by past observational and laboratory charging studies, suggests that broad, strong updrafts and associated large liquid water contents...

  19. Climate Dynamics Observational, Theoretical and

    E-Print Network [OSTI]

    Dong, Xiquan

    1 23 Climate Dynamics Observational, Theoretical and Computational Research on the Climate System.6, and -22.5 Wm-2 , respectively, indicating a net cooling effect of clouds on the TOA radiation budget-2 , respectively, resulting in a larger net cooling effect of 2.9 Wm-2 in the model simu- lations

  20. Development and Testing of a Life Cycle Model and a Parameterization of Thin Mid-level Stratiform Clouds

    SciTech Connect (OSTI)

    Krueger, Steven K.

    2008-03-03T23:59:59.000Z

    We used a cloud-resolving model (a detailed computer model of cloud systems) to evaluate and improve the representation of clouds in global atmospheric models used for numerical weather prediction and climate modeling. We also used observations of the atmospheric state, including clouds, made at DOE's Atmospheric Radiation Measurement (ARM) Program's Climate Research Facility located in the Southern Great Plains (Kansas and Oklahoma) during Intensive Observation Periods to evaluate our detailed computer model as well as a single-column version of a global atmospheric model used for numerical weather prediction (the Global Forecast System of the NOAA National Centers for Environmental Prediction). This so-called Single-Column Modeling approach has proved to be a very effective method for testing the representation of clouds in global atmospheric models. The method relies on detailed observations of the atmospheric state, including clouds, in an atmospheric column comparable in size to a grid column used in a global atmospheric model. The required observations are made by a combination of in situ and remote sensing instruments. One of the greatest problems facing mankind at the present is climate change. Part of the problem is our limited ability to predict the regional patterns of climate change. In order to increase this ability, uncertainties in climate models must be reduced. One of the greatest of these uncertainties is the representation of clouds and cloud processes. This project, and ARM taken as a whole, has helped to improve the representation of clouds in global atmospheric models.

  1. Cloud Computing and Validation of Expandable In Silico Livers

    E-Print Network [OSTI]

    Ropella, Glen EP; Hunt, C Anthony

    2010-01-01T23:59:59.000Z

    benefit analysis of cloud computing versus desktop grids.as: Ropella and Hunt: Cloud computing and validation ofCloud computing and validation of expandable in silico

  2. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kalesse, Heike

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  3. Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Avramov, A.; Harringston, J.Y.; Verlinde, J.

    2005-03-18T23:59:59.000Z

    Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic (Curry et al. 2000) and through various feedback mechanisms exert a strong influence on the Arctic climate. Perhaps one of the most intriguing of their features is that they tend to have liquid tops that precipitate ice. Despite the fact that this situation is colloidally unstable, these cloud systems are quite long lived - from a few days to over a couple of weeks. It has been hypothesized that mixed-phase clouds are maintained through a balance between liquid water condensation resulting from the cloud-top radiative cooling and ice removal by precipitation (Pinto 1998; Harrington et al. 1999). In their modeling study Harrington et al. (1999) found that the maintenance of this balance depends strongly on the ambient concentration of ice forming nucleus (IFN). In a follow-up study, Jiang et al. (2002), using only 30% of IFN concentration predicted by Meyers et al. (1992) IFN parameterization were able to obtain results similar to the observations reported by Pinto (1998). The IFN concentration measurements collected during the Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004 over the North Slope of Alaska and the Beaufort Sea (Verlinde et al. 2005), also showed much lower values then those predicted (Prenne, pers. comm.) by currently accepted ice nucleation parameterizations (e.g. Meyers et al. 1992). The goal of this study is to use the extensive IFN data taken during M-PACE to examine what effects low IFN concentrations have on mesoscale cloud structure and coastal dynamics.

  4. Title: Networking the Cloud: Enabling Enterprise Computing and Storage Cloud computing has been changing how enterprises run and manage their IT systems. Cloud

    E-Print Network [OSTI]

    Title: Networking the Cloud: Enabling Enterprise Computing and Storage Abstract: Cloud computing has been changing how enterprises run and manage their IT systems. Cloud computing platforms provide introduction on Cloud Computing. We propose a Virtual Cloud Pool abstraction to logically unify cloud

  5. Cluster analysis of cloud properties : a method for diagnosing cloud-climate feedbacks

    E-Print Network [OSTI]

    Gordon, Neil D.

    2008-01-01T23:59:59.000Z

    represent cloud effects on gridbox mean visible radiationclouds and the resulting effect on the balance of radiationrepresent cloud effects on grid-box-mean visible radiation

  6. The Evolution of Cloud Computing in ATLAS

    E-Print Network [OSTI]

    Taylor, Ryan P.; The ATLAS collaboration; Love, Peter; Leblanc, Matthew Edgar; Di Girolamo, Alessandro; Paterson, Michael; Gable, Ian; Sobie, Randall; Field, Laurence

    2015-01-01T23:59:59.000Z

    The ATLAS experiment has successfully incorporated cloud computing technology and cloud resources into its primarily grid-based model of distributed computing. Cloud R&D activities continue to mature and transition into stable production systems, while ongoing evolutionary changes are still needed to adapt and refine the approaches used, in response to changes in prevailing cloud technology. In addition, completely new developments are needed to handle emerging requirements. This work will describe the overall evolution of cloud computing in ATLAS. The current status of the VM management systems used for harnessing IAAS resources will be discussed. Monitoring and accounting systems tailored for clouds are needed to complete the integration of cloud resources within ATLAS' distributed computing framework. We are developing and deploying new solutions to address the challenge of operation in a geographically distributed multi-cloud scenario, including a system for managing VM images across multiple clouds, ...

  7. From the warm magnetized atomic medium to molecular clouds

    E-Print Network [OSTI]

    P. Hennebelle; R. Banerjee; E. Vazquez-Semadeni; R. Klessen; E. Audit

    2008-05-09T23:59:59.000Z

    {It has recently been proposed that giant molecular complexes form at the sites where streams of diffuse warm atomic gas collide at transonic velocities.} {We study the global statistics of molecular clouds formed by large scale colliding flows of warm neutral atomic interstellar gas under ideal MHD conditions. The flows deliver material as well as kinetic energy and trigger thermal instability leading eventually to gravitational collapse.} {We perform adaptive mesh refinement MHD simulations which, for the first time in this context, treat self-consistently cooling and self-gravity.} {The clouds formed in the simulations develop a highly inhomogeneous density and temperature structure, with cold dense filaments and clumps condensing from converging flows of warm atomic gas. In the clouds, the column density probability density distribution (PDF) peaks at $\\sim 2 \\times 10^{21} \\psc$ and decays rapidly at higher values; the magnetic intensity correlates weakly with density from $n \\sim 0.1$ to $10^4 \\pcc$, and then varies roughly as $n^{1/2}$ for higher densities.} {The global statistical properties of such molecular clouds are reasonably consistent with observational determinations. Our numerical simulations suggest that molecular clouds formed by the moderately supersonic collision of warm atomic gas streams.}

  8. Tropical Warm Pool International Cloud Experiment (TWP-ICE): Cloud and Rain Characteristics in the Australian Monsoon

    SciTech Connect (OSTI)

    PT May; C Jakob; JH Mather

    2004-05-30T23:59:59.000Z

    The impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool – International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them. The experiment is a collaboration between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program, the Bureau of Meteorology (BoM), the National Aeronautics and Space Administration (NASA), the European Commission DG RTD-1.2, and several United States, Australian, Canadian, and European Universities. This experiment will be undertaken over a 4-week period in early 2006. January and February corresponds to the wet phase of the Australia monsoon. This season has been selected because, despite Darwin’s coastal location, the convection that occurs over and near Darwin at this time is largely of maritime origin with a large fetch over water. Based on previous experiments, the convection appears typical of maritime convection with widespread convection that has complex organization, but is not as deep or as intense as continental or coastal convection. Therefore, it is expected that the convection and cloud characteristics will be representative of conditions typical for wide areas of the tropics.

  9. An Analysis of Cloud Cover and Water Vapor for the ALMA Project

    E-Print Network [OSTI]

    (Chile), Chalviri (Bolivia) and Five Sites in Argentina using Satellite Data and a Verification and water vapor at Chajnantor (Chile), Chalviri (Bolivia) and four sites in Argentina. Since time

  10. Accounting for Circumsolar and Horizon Cloud Determination Errors in Sky Image Inferral of Sky Cover

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In theACMEAccountable Property

  11. Equivalence demonstration of an alternative cover system 307 EQUIVALENCE DEMONSTRATION OF AN ALTERNATIVE COVER SYSTEM

    E-Print Network [OSTI]

    Zornberg, Jorge G.

    engineered components of municipal and hazardous waste landfills is the cover system. The cover system should systems for arid locations has been acknowledged by field experimental assessments (e.g., Anderson et al for final cover design at hazardous waste sites. Evapotranspirative covers are also referred

  12. Global Climate Change,Global Climate Change, Land Cover Change, andLand Cover Change, and

    E-Print Network [OSTI]

    1 Global Climate Change,Global Climate Change, Land Cover Change, andLand Cover Change Changes · Due to ­ Climate Change ­ Land Cover / Land Use Change ­ Interaction of Climate and Land Cover Change · Resolution ­ Space ­ Time Hydro-Climatic Change · Variability vs. Change (Trends) · Point data

  13. Low virial parameters in molecular clouds: Implications for high-mass star formation and magnetic fields

    SciTech Connect (OSTI)

    Kauffmann, Jens; Pillai, Thushara [Astronomy Department, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Goldsmith, Paul F., E-mail: jens.kauffmann@astro.caltech.edu, E-mail: tpillai@astro.caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States)

    2013-12-20T23:59:59.000Z

    Whether or not molecular clouds and embedded cloud fragments are stable against collapse is of utmost importance for the study of the star formation process. Only 'supercritical' cloud fragments are able to collapse and form stars. The virial parameter ? = M {sub vir}/M, which compares the virial mass to the actual mass, provides one way to gauge stability against collapse. Supercritical cloud fragments are characterized by ? ? 2, as indicated by a comprehensive stability analysis considering perturbations in pressure and density gradients. Past research has suggested that virial parameters ? ? 2 prevail in clouds. This would suggest that collapse toward star formation is a gradual and relatively slow process and that magnetic fields are not needed to explain the observed cloud structure. Here, we review a range of very recent observational studies that derive virial parameters <<2 and compile a catalog of 1325 virial parameter estimates. Low values of ? are in particular observed for regions of high-mass star formation (HMSF). These observations may argue for a more rapid and violent evolution during collapse. This would enable 'competitive accretion' in HMSF, constrain some models of 'monolithic collapse', and might explain the absence of high-mass starless cores. Alternatively, the data could point at the presence of significant magnetic fields ?1 mG at high gas densities. We examine to what extent the derived observational properties might be biased by observational or theoretical uncertainties. For a wide range of reasonable parameters, our conclusions appear to be robust with respect to such biases.

  14. Aerosol Observing System (AOS) Handbook

    SciTech Connect (OSTI)

    Jefferson, A

    2011-01-17T23:59:59.000Z

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  15. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

    SciTech Connect (OSTI)

    Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying

    2015-01-01T23:59:59.000Z

    A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they will be included in a future public release of WRF-Chem.

  16. AN INVESTIGATION ON THE MORPHOLOGICAL EVOLUTION OF BRIGHT-RIMMED CLOUDS

    SciTech Connect (OSTI)

    Miao Jingqi [Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NR (United Kingdom); White, Glenn J. [Centre for Earth, Planetary, Space and Astronomical Research, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Thompson, M. A. [School of Physics Astronomy and Maths, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Nelson, Richard P. [School of Mathematical Sciences, Queen Mary College, University of London, Mile End Road, London E1 4NS (United Kingdom)], E-mail: J.Miao@kent.ac.uk

    2009-02-10T23:59:59.000Z

    A new radiative driven implosion (RDI) model based on smoothed particle hydrodynamics technique is developed and applied to investigate the morphological evolutions of molecular clouds under the effect of ionizing radiation. This model self-consistently includes the self-gravity of the cloud in the hydrodynamical evolution, the UV radiation component in the radiation transferring equations, the relevant heating and cooling mechanisms in the energy evolution, and a comprehensive chemical network. The simulation results reveal that under the effect of ionizing radiation, a molecular cloud may evolve through different evolutionary sequences. Depending on its initial gravitational state, the evolution of a molecular cloud does not necessarily follow a complete morphological evolution sequence from type A{yields}B{yields}C, as described by previous RDI models. When confronted with observations, the simulation results provide satisfactory physical explanations for a series of puzzles derived from bright-rimmed clouds observations. The consistency of the modeling results with observations shows that the self-gravity of a molecular cloud should not be neglected in any investigation on the dynamical evolution of molecular clouds when they are exposed to ionizing radiation.

  17. An Investigation on the Morphological Evolution of Bright-Rimmed Clouds

    E-Print Network [OSTI]

    J. Miao; G. J. White; M. A. Thompson; R. P. Nelson

    2008-10-15T23:59:59.000Z

    A new Radiative Driven Implosion (RDI) model based on Smoothed Particle Hydrodynamics (SPH) technique is developed and applied to investigate the morphological evolutions of molecular clouds under the effect of ionising radiation. This model self-consistently includes the self-gravity of the cloud in the hydrodynamical evolution, the UV radiation component in the radiation transfer equations, the relevant heating and cooling mechanisms in the energy evolution and a comprehensive chemical network. The simulation results reveal that under the effect of ionising radiation, a molecular cloud may evolve through different evolutionary sequences. Dependent on its initial gravitational state, the evolution of a molecular cloud does not necessarily follow a complete morphological evolution sequence from type A to B to C, as described by previous RDI models. When confronted with observations, the simulation results provide satisfactory physical explanations for a series of puzzles derived from Bright-Rimmed Clouds (BRCs) observations. The consistency of the modelling results with observations shows that the self-gravity of a molecular cloud should not be neglected in any investigation on the dynamical evolution of molecular clouds when they are exposed to ionising radiation.

  18. Global circulation as the main source of cloud activity on Titan

    E-Print Network [OSTI]

    Rodriguez, Sébastien; Rannou, Pascal; Tobie, Gabriel; Baines, Kevin H; Barnes, Jason W; Griffith, Caitlin A; Hirtzig, Mathieu; Pitman, Karly M; Sotin, Christophe; Brown, Robert H; Buratti, Bonnie J; Clark, Roger N; Nicholson, Phil D; 10.1038/NATURE08014

    2009-01-01T23:59:59.000Z

    Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole, resulting from the subsidence and condensation of ethane-rich air into the colder troposphere. General circulation models predict that this distribution should change with the seasons on a 15-year timescale, and that clouds should develop under certain circumstances at temperate latitudes (~40\\degree) in the winter hemisphere. The models, however, have hitherto been poorly constrained and their long-term predictions have not yet been observationally verified. Here we report that the global spatial cloud coverage on Titan is in general agreement with the models, confirming that cloud activity is mainly controlled by the global circ...

  19. Dust takes detour on ice-cloud journey | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dust takes detour on ice-cloud journey Dust takes detour on ice-cloud journey Pollution-coated particles bypass ice formation, but influence clouds Cirrus clouds are composed of...

  20. Tiny HI Clouds in the Local ISM

    E-Print Network [OSTI]

    Robert Braun; Nissim Kanekar

    2005-06-08T23:59:59.000Z

    We report deep, high spectral resolution WSRT HI 21cm observations of four high latitude compact radio sources, that have revealed a new population of tiny, discrete clouds in the diffuse ISM, with peak optical depths tau ~ 0.1-2%, HI column densities of 0.4-8 * 10^{18} cm^{-2} and core temperatures of 20-80 K. Imaging detections confirm these low column densities and imply linear core dimensions of a few thousand AU, assuming a distance of 100 pc. The physical origin of these tiny HI structures and their distribution in the ISM is at present unknown. Further observations will be required to determine whether they are a ubiquitous component of the ISM.

  1. Compact High Velocity Clouds

    E-Print Network [OSTI]

    Robert Braun

    2000-09-01T23:59:59.000Z

    We summarize the observed properties of the CHVC population, which provide strong evidence for source distances in the range 200-1000 kpc. At these distances, the population corresponds to strongly dark-matter dominated sub-dwarf galaxies still accreting onto the more massive Local Group systems. Recent searches for faint associated stellar populations have revealed red-giant candidates for which follow-up spectroscopy is scheduled. A sensitive HI survey for CHVC counterparts in the NGC 628 galaxy group has allowed tentative detection of 40 candidates, for which confirming observations have been approved. Many open issues should be resolved by observational programs within the coming years.

  2. Refinement, Validation and Application of Cloud-Radiation Parameterization in a GCM

    SciTech Connect (OSTI)

    Dr. Graeme L. Stephens

    2009-04-30T23:59:59.000Z

    The research performed under this award was conducted along 3 related fronts: (1) Refinement and assessment of parameterizations of sub-grid scale radiative transport in GCMs. (2) Diagnostic studies that use ARM observations of clouds and convection in an effort to understand the effects of moist convection on its environment, including how convection influences clouds and radiation. This aspect focuses on developing and testing methodologies designed to use ARM data more effectively for use in atmospheric models, both at the cloud resolving model scale and the global climate model scale. (3) Use (1) and (2) in combination with both models and observations of varying complexity to study key radiation feedback Our work toward these objectives thus involved three corresponding efforts. First, novel diagnostic techniques were developed and applied to ARM observations to understand and characterize the effects of moist convection on the dynamical and thermodynamical environment in which it occurs. Second, an in house GCM radiative transfer algorithm (BUGSrad) was employed along with an optimal estimation cloud retrieval algorithm to evaluate the ability to reproduce cloudy-sky radiative flux observations. Assessments using a range of GCMs with various moist convective parameterizations to evaluate the fidelity with which the parameterizations reproduce key observable features of the environment were also started in the final year of this award. The third study area involved the study of cloud radiation feedbacks and we examined these in both cloud resolving and global climate models.

  3. Covered Product Category: Residential Central Air Conditioners...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Central Air Conditioners Covered Product Category: Residential Central Air Conditioners The Federal Energy Management Program (FEMP) provides acquisition guidance for residential...

  4. Covered Product Category: Hot Food Holding Cabinets

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for hot food holding cabinets, which are covered by the ENERGY STAR program.

  5. Covered Product Category: Commercial Steam Cookers

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial steam cookers, which are covered by the ENERGY STAR program.

  6. Covered Product Category: Residential Electric Resistance Water...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Electric Resistance Water Heaters Covered Product Category: Residential Electric Resistance Water Heaters The Federal Energy Management Program (FEMP) sets federal efficiency...

  7. Covered Product Category: Commercial Refrigerators and Freezers

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial refrigerators and freezers, which are covered by the ENERGY STAR program.

  8. Socially Optimal Pricing of Cloud Computing Resources

    E-Print Network [OSTI]

    Menache, Ishai

    The cloud computing paradigm offers easily accessible computing resources of variable size and capabilities. We consider a cloud-computing facility that provides simultaneous service to a heterogeneous, time-varying ...

  9. The Evolution of Cloud Computing in ATLAS

    E-Print Network [OSTI]

    Taylor, Ryan P; The ATLAS collaboration; Brasolin, Franco; Cordeiro, Cristovao; Desmarais, Ron; Field, Laurence; Gable, Ian; Giordano, Domenico; Di Girolamo, Alessandro; Hover, John; Leblanc, Matthew Edgar; Love, Peter; Paterson, Michael; Sobie, Randall; Zaytsev, Alexandr

    2015-01-01T23:59:59.000Z

    The ATLAS experiment has successfully incorporated cloud computing technology and cloud resources into its primarily grid-based model of distributed computing. Cloud R&D activities continue to mature and transition into stable production systems, while ongoing evolutionary changes are still needed to adapt and refine the approaches used, in response to changes in prevailing cloud technology. In addition, completely new developments are needed to handle emerging requirements. This paper describes the overall evolution of cloud computing in ATLAS. The current status of the virtual machine (VM) management systems used for harnessing infrastructure as a service (IaaS) resources are discussed. Monitoring and accounting systems tailored for clouds are needed to complete the integration of cloud resources within ATLAS' distributed computing framework. We are developing and deploying new solutions to address the challenge of operation in a geographically distributed multi-cloud scenario, including a system for ma...

  10. Disruptive technology business models in cloud computing

    E-Print Network [OSTI]

    Krikos, Alexis Christopher

    2010-01-01T23:59:59.000Z

    Cloud computing, a term whose origins have been in existence for more than a decade, has come into fruition due to technological capabilities and marketplace demands. Cloud computing can be defined as a scalable and flexible ...

  11. Cloud-Top Temperatures for Precipitating Winter Clouds JAY W. HANNA

    E-Print Network [OSTI]

    Schultz, David

    1 Cloud-Top Temperatures for Precipitating Winter Clouds JAY W. HANNA NOAA/NESDIS Satellite of satellite-derived cloud-top brightness temperatures from GOES longwave infrared (channel 4) satellite data, rain, freezing rain, and sleet. The distributions of cloud-top brightness temperatures were constructed

  12. Cloud networking and communications Cloud computing is having an important impact on

    E-Print Network [OSTI]

    Boutaba, Raouf

    Editorial Cloud networking and communications Cloud computing is having an important impact attention has been devoted to system aspects of Cloud computing. More recently, however, the focus is shifting towards Cloud net- working and communications with evolutionary and revo- lutionary propositions

  13. Cloud seeding as a technique for studying aerosol-cloud interactions in marine stratocumulus

    E-Print Network [OSTI]

    Miami, University of

    Cloud seeding as a technique for studying aerosol-cloud interactions in marine stratocumulus hygroscopic aerosols were introduced into a solid marine stratocumulus cloud (200 m thick) by burning hygroscopic flares mounted on an aircraft. The cloud microphysical response in two parallel seeding plumes

  14. The Cloud Adoption Toolkit: Supporting Cloud Adoption Decisions in the Enterprise

    E-Print Network [OSTI]

    Sommerville, Ian

    1 The Cloud Adoption Toolkit: Supporting Cloud Adoption Decisions in the Enterprise Ali Khajeh-Hosseini, David Greenwood, James W. Smith, Ian Sommerville Cloud Computing Co-laboratory, School of Computer Science University of St Andrews, UK {akh, dsg22, jws7, ifs}@cs.st-andrews.ac.uk Abstract Cloud computing

  15. CLOUD COMPUTING AND INFORMATION POLICY 1 Cloud Computing and Information Policy

    E-Print Network [OSTI]

    Lin, Jimmy

    CLOUD COMPUTING AND INFORMATION POLICY 1 Cloud Computing and Information Policy: Computing in a Policy Cloud? Forthcoming in the Journal of Information Technology and Politics, 5(3). Paul T. Jaeger University of Maryland Jimmy Lin University of Maryland Justin M. Grimes University of Maryland #12;CLOUD

  16. HPI Cloud Symposium ,Operating The Cloud` 25.09.2013, Hasso-Plattner-Institut, Auditorium Building

    E-Print Network [OSTI]

    Weske, Mathias

    Agenda HPI Cloud Symposium ,Operating The Cloud` 25.09.2013, Hasso-Plattner-Institut, Auditorium Building 09:30h Registration 10:00h Opening Prof. Dr. Christoph Meinel, HPI Potsdam 10:30h Cloud-RAID: Eine Methode zur Bereitstellung zuverlässiger Speicherressourcen in Öffentlichen Clouds Maxim Schnajkin, HPI

  17. Cloud Verifier: Verifiable Auditing Service for IaaS Clouds Joshua Schiffman

    E-Print Network [OSTI]

    Jaeger, Trent

    Cloud Verifier: Verifiable Auditing Service for IaaS Clouds Joshua Schiffman Security Architecture University Park, PA, USA yus138,hvijay,tjaeger@cse.psu.edu Abstract--Cloud computing has commoditized compute paradigm, its adoption has been stymied by cloud platform's lack of trans- parency, which leaves customers

  18. Cloud Tracking in Cloud-Resolving Models R. S. Plant1

    E-Print Network [OSTI]

    Plant, Robert

    Cloud Tracking in Cloud-Resolving Models R. S. Plant1 1 Department of Meteorology, University. INTRODUCTION In recent years Cloud Resolving Models (CRMs) have become an increasingly important tool for CRM data, which allows one to investigate statistical prop- erties of the lifecycles of the "clouds

  19. From mini-clouds to Cloud Computing Boris Mejias, Peter Van Roy

    E-Print Network [OSTI]

    Bonaventure, Olivier

    From mini-clouds to Cloud Computing Boris Mej´ias, Peter Van Roy Universit´e catholique de Louvain ­ Belgium {boris.mejias|peter.vanroy}@uclouvain.be Abstract Cloud computing has many definitions with different views within industry and academia, but everybody agrees on that cloud computing is the way

  20. AnonymousCloud: A Data Ownership Privacy Provider Framework in Cloud Computing

    E-Print Network [OSTI]

    Hamlen, Kevin W.

    AnonymousCloud: A Data Ownership Privacy Provider Framework in Cloud Computing Safwan Mahmud Khan their computation results are ultimately delivered. To provide this data ownership privacy, the cloud's distributed-anonymity; authentication; cloud computing; in- formation security; privacy; Tor I. INTRODUCTION Revolutionary advances

  1. Leveraging Platform Basic Services in Cloud Application Platforms for the Development of Cloud

    E-Print Network [OSTI]

    Simons, Anthony J. H.

    Leveraging Platform Basic Services in Cloud Application Platforms for the Development of Cloud.Simons@dcs.shef.ac.uk Abstract-- Cloud application platforms gain popularity and have the potential to alter the way service based cloud applications are developed involving utilisation of platform basic services. A platform

  2. Fractal dimension of interstellar clouds: opacity and noise effects

    E-Print Network [OSTI]

    Nestor Sanchez; Emilio J. Alfaro; Enrique Perez

    2006-10-20T23:59:59.000Z

    There exists observational evidence that the interstellar medium has a fractal structure in a wide range of spatial scales. The measurement of the fractal dimension (Df) of interstellar clouds is a simple way to characterize this fractal structure, but several factors, both intrinsic to the clouds and to the observations, may contribute to affect the values obtained. In this work we study the effects that opacity and noise have on the determination of Df. We focus on two different fractal dimension estimators: the perimeter-area based dimension (Dper) and the mass-size dimension (Dm). We first use simulated fractal clouds to show that opacity does not affect the estimation of Dper. However, Dm tends to increase as opacity increases and this estimator fails when applied to optically thick regions. In addition, very noisy maps can seriously affect the estimation of both Dper and Dm, decreasing the final estimation of Df. We apply these methods to emission maps of Ophiuchus, Perseus and Orion molecular clouds in different molecular lines and we obtain that the fractal dimension is always in the range 2.6 2.3) average fractal dimension for the interstellar medium, as traced by different chemical species.

  3. Using Surface Remote Sensors to Derive Radiative Characteristics of Mixed-Phase Clouds: An Example from M-PACE

    SciTech Connect (OSTI)

    de Boer, Gijs; Collins, William D.; Menon, Surabi; Long, Charles N.

    2011-12-02T23:59:59.000Z

    Measurements from ground-based cloud radar, high spectral resolution lidar and microwave radiometer are used in conjunction with a column version of the Rapid Radiative Transfer Model (RRTMG) and radiosonde measurements to derive the surface radiative properties under mixed-phase cloud conditions. These clouds were observed during the United States Department of Energy (US DOE) Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment (M-PACE) between September and November of 2004. In total, sixteen half hour time periods are reviewed due to their coincidence with radiosonde launches. Cloud liquid (ice) water paths are found to range between 11.0-366.4 (0.5-114.1) gm-2, and cloud physical thicknesses fall between 286-2075 m. Combined with temperature and hydrometeor size estimates, this information is used to calculate surface radiative flux densities using RRTMG, which are demonstrated to generally agree with measured flux densities from surface-based radiometric instrumentation. Errors in longwave flux density estimates are found to be largest for thin clouds, while shortwave flux density errors are generally largest for thicker clouds. A sensitivity study is performed to understand the impact of retrieval assumptions and uncertainties on derived surface radiation estimates. Cloud radiative forcing is calculated for all profiles, illustrating longwave dominance during this time of year, with net cloud forcing generally between 50 and 90 Wm-2.

  4. Carbon Chemistry in interstellar clouds

    E-Print Network [OSTI]

    Maryvonne Gerin; David Fosse; Evelyne Roueff

    2002-12-03T23:59:59.000Z

    We discuss new developments of interstellar chemistry, with particular emphasis on the carbon chemistry. We confirm that carbon chains and cycles are ubiquitous in the ISM and closely chemically related to ea ch other, and to carbon. Investigation of the carbon budget in shielded and UV illuminated gas shows that the inventory of interstellar molecules is not complete and more complex molecules with 4 or more carbon atoms must be present. Finally we discuss the consequences for the evolution of clouds and conclude that the ubiquitous presence of carbon chains and cycles is not a necessary consequence of a very young age for interstellar clouds.

  5. Kordylewski clouds: the observational object for the most ambitious.

    E-Print Network [OSTI]

    Mrozek, Tomasz

    of Sciences #12;A bit of history Tycho Brahe Johannes Kepler Tycho Brahe carried out extremely accurate visual

  6. Aerosol, Cloud, and Climate: From Observation to Model

    ScienceCinema (OSTI)

    Jian Wang

    2010-09-01T23:59:59.000Z

    Scientists have long been investigating this phenomenon of "global warming," which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions.

  7. Gulf of Mexico cloud observations and the atmospheric water budget

    E-Print Network [OSTI]

    Banks, Richard Wesley

    1963-01-01T23:59:59.000Z

    x '3 + 0. 75 . ?. , 3 ~ 0. /3 I 0. 40 X4 24. 85 0. 5959 0. 3551 24. 67 0. 6038 0. 3645 24. 29 24. 52 23. 14 O. el93 0. 383e 0. 6099 0. 3/20 0. 6641 0. 4410 22. 97 22. 75 22. 86 O. e'00 0. 6778 0. 6739 0. 4489 0. 4595 0. 4541 29... 12. 63 12. r 5 0. 9091 0. 9335 n, 93&7 0, 8264 0. 6345 0, 8'3'39 24. 38 0. 6194 0. 3836 24. 60 0. 6099 0. 3720 23. 19 0. 6648 0. 4439 23. 04 0. 6702 0. 4492 22. 82 0. 6780 0. 4596 22. 94 0. 6740 0. 4543 IABLE 7. (continued7 ?JLTIPLE...

  8. Aerosol, Cloud, and Climate: From Observation to Model

    SciTech Connect (OSTI)

    Jian Wang

    2010-05-12T23:59:59.000Z

    Scientists have long been investigating this phenomenon of "global warming," which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions.

  9. Radiosonde observations at Pt. Reyes and cloud properties retrieved from

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection Radiation Protection Regulations:Radiological ThreatGOES-WEST

  10. Interdisciplinary Pest Management Potentials of Cover Cropping Systems

    E-Print Network [OSTI]

    Bachie, Oli Gurmu

    2011-01-01T23:59:59.000Z

    Cover Crops: Cowpea, Sunn Hemp, and Velvetbean. HottscienceCover Crops: Cowpea, Sunn Hemp, and Velvetbean. Hottsciencethan grasses using sun hemp mulches. While cover cropping

  11. Using a cloud resolving model to generate the beam-filling correction for microwave retrieval of oceanic rainfall

    E-Print Network [OSTI]

    Feng, Kai

    2003-01-01T23:59:59.000Z

    ), respectively. They have a parameterized two-class liquid water (cloud water and rain) and a parameterized three-class ice-phase scheme (cloud ice, snow, and graupel). A tropical squall line has been observed on 29 August 1999 during the Kwajalein Experiment...

  12. Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

    SciTech Connect (OSTI)

    Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

    2013-08-16T23:59:59.000Z

    Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

  13. Interactive physically-based cloud simulation

    E-Print Network [OSTI]

    Overby, Derek Robert

    2002-01-01T23:59:59.000Z

    of digital artistic media. Previous methods for modeling the growth of clouds do not account for the fluid interactions that are responsible for cloud formation in the physical atmosphere. We propose a model for simulating cloud formation based on a basic...

  14. Dynamics of Clouds Fall Semester 2012

    E-Print Network [OSTI]

    ATS712 Dynamics of Clouds Fall Semester 2012 Meeting Times: T/Th: 9-10:15am Room: ATS 101-2pm Course Description: This class focuses on the general dynamics of cloud systems. Models of fog and other Tools / Skills Cotton, W.R., G.H. Bryan, and S.C. van den Heever, 2010: Storm and Cloud Dynamics

  15. Microsoft Private Cloud Title of document

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Microsoft Private Cloud Title of document 1 1 Microsoft Private Cloud A Comparative Look at Functionality, Benefits, and Economics November2012 #12;Microsoft Private Cloud Title of document 2 2 Copyright Information © 2012 Microsoft Corporation. All rights reserved. This document is provided "as-is." Information

  16. Performance Engineering for Cloud Computing John Murphy

    E-Print Network [OSTI]

    Murphy, John

    Performance Engineering for Cloud Computing John Murphy Lero ­ The Irish Software Engineering.Murphy@ucd.ie Abstract. Cloud computing potentially solves some of the major challenges in the engineering of large efficient operation. This paper argues that cloud computing is an area where performance engineering must

  17. Level Set Implementations on Unstructured Point Cloud

    E-Print Network [OSTI]

    Duncan, James S.

    Level Set Implementations on Unstructured Point Cloud by HO, Hon Pong A Thesis Submitted;Level Set Implementations on Unstructured Point Cloud by HO, Hon Pong This is to certify that I have implementations on unstructured point cloud 15 3.1 Level set initialization

  18. 6, 93519388, 2006 Aerosol-cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al Chemistry and Physics Discussions Aerosol-cloud interaction inferred from MODIS satellite data and global 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al. Title

  19. Cloud Security: Issues and Concerns Pierangela Samarati*

    E-Print Network [OSTI]

    Samarati, Pierangela

    1 Cloud Security: Issues and Concerns Authors Pierangela Samarati* Università degli Studi di Milano, Italy sabrina.decapitani@unimi.it Keywords cloud security confidentiality integrity availability secure data storage and processing Summary The cloud has emerged as a successful computing paradigm

  20. Cloud Computing: Centralization and Data Sovereignty

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Cloud Computing: Centralization and Data Sovereignty Primavera De Filippi, Smari McCarthy Abstract: Cloud computing can be defined as the provision of computing resources on-demand over and elasticity of costs, problems arise concerning the collection of personal information in the Cloud

  1. Optimizing Offloading Strategies in Mobile Cloud Computing

    E-Print Network [OSTI]

    Hyytiä, Esa

    Optimizing Offloading Strategies in Mobile Cloud Computing Esa Hyyti¨a Department of Communications Abstract--We consider a dynamic offloading problem arising in the context of mobile cloud computing (MCC consider the task assignment problem arising in the context of the mobile cloud computing (MCC). In MCC

  2. CONTROLLING DATA IN THE CLOUD: OUTSOURCING COMPUTATION

    E-Print Network [OSTI]

    Zou, Cliff C.

    #12;CONTROLLING DATA IN THE CLOUD: OUTSOURCING COMPUTATION WITHOUT OUTSOURCING CONTROL Paper By Laboratories Of America 2009 ACM WORKSHOP ON CLOUD COMPUTING SECURITY (CCSW 2009) Presented By Talal Basaif CAP that will arise later · New directions to solve some issues #12;INTRODUCTION · Cloud computing is one of desirable

  3. Towards a Ubiquitous Cloud Computing Infrastructure

    E-Print Network [OSTI]

    van der Merwe, Kobus

    Towards a Ubiquitous Cloud Computing Infrastructure Jacobus Van der Merwe, K.K. Ramakrishnan of a number of cloud computing use cases. We specifically consider cloudbursting and follow-the-sun and focus that are also network service providers. I. INTRODUCTION Cloud computing is rapidly gaining acceptance

  4. Cloud Computing: Legal Issues in Centralized Architectures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Cloud Computing: Legal Issues in Centralized Architectures Primavera DE FILIPPI1 , Smari McCARTHY2, Reykjavik, 101, Iceland - Email: smari@gmail.com Abstract: Cloud computing can be defined as the provision they can access their data and the extent to which parties can exploit it. Keywords: Cloud Computing

  5. Cloud and Star Formation in Disk Galaxy Models with Feedback

    E-Print Network [OSTI]

    Rahul Shetty; Eve C. Ostriker

    2008-05-26T23:59:59.000Z

    We include feedback in global hydrodynamic simulations in order to study the star formation properties, and gas structure and dynamics, in models of galactic disks. We extend previous models by implementing feedback in gravitationally bound clouds: momentum is injected at a rate proportional to the star formation rate. This mechanical energy disperses cloud gas back into the surrounding ISM, truncating star formation in a given cloud, and raising the overall level of ambient turbulence. Propagating star formation can however occur as expanding shells collide, enhancing the density and triggering new cloud and star formation. By controlling the momentum injection per massive star and the specific star formation rate in dense gas, we find that the negative effects of high turbulence outweigh the positive ones, and in net feedback reduces the fraction of dense gas and thus the overall star formation rate. The properties of the large clouds that form are not, however, very sensitive to feedback, with cutoff masses of a few million solar masses, similar to observations. We find a relationship between the star formation rate surface density and the gas surface density with a power law index ~2 for our models with the largest dynamic range, consistent with theoretical expectations for our model of disk flaring. We point out that the value of the "Kennicutt-Schmidt" index depends on the thickness of the disk. With our simple feedback prescription (a single combined star formation event per cloud), we find that global spiral patterns are not sustained; less correlated feedback and smaller scale turbulence appear to be necessary for spiral patterns to persist.

  6. The Temperature of Interstellar Clouds from Turbulent Heating

    E-Print Network [OSTI]

    Liubin Pan; Paolo Padoan

    2008-10-22T23:59:59.000Z

    To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the dimension of the most dissipative structures. By comparing the model with the probability distribution of the turbulent dissipation rate in a simulation of supersonic and super-Alfvenic turbulence, we find a best-fit value of d=1.64. We apply this intermittency model to the computation of the mass-weighted probability distribution of the gas temperature of molecular clouds, high-mass star-forming cores, and cold diffuse HI clouds. Our main results are: i) The mean gas temperature in molecular clouds can be explained as the effect of turbulent heating alone, while cosmic ray heating may dominate only in regions where the turbulent heating is low; ii) The mean gas temperature in high-mass star-forming cores with typical FWHM of ~6 km/s (corresponding to a 1D rms velocity of 2.5 km/s) may be completely controlled by turbulent heating, which predicts a mean value of approximately 36 K, two to three times larger than the mean gas temperature in the absence of turbulent heating; iii) The intermittency of the turbulent heating can generate enough hot regions in cold diffuse HI clouds to explain the observed CH+ abundance, if the rms velocity on a scale of 1 pc is at least 3 km/s, in agreement with previous results based on incompressible turbulence. Because of its importance in the thermal balance of molecular clouds and high-mass star-forming cores, the process of turbulent heating may be central in setting the characteristic stellar mass and in regulating molecular chemical reactions.

  7. Distances and Metallicities of High- and Intermediate-Velocity Clouds

    E-Print Network [OSTI]

    B. P. Wakker

    2001-02-08T23:59:59.000Z

    A table is presented that summarizes published absorption line measurements for the high- and intermediate velocity clouds (HVCs and IVCs). New values are derived for N(HI) in the direction of observed probes, in order to arrive at reliable abundances and abundance limits (the HI data are described in Paper II). Distances to stellar probes are revisited and calculated consistently, in order to derive distance brackets or limits for many of the clouds, taking care to properly interpret non-detections. The main conclusions are the following. 1) Absolute abundances have been measured using lines of SII, NI and OI, with the following resulting values: ~0.1 solar for one HVC (complex C), ~0.3 solar for the Magellanic Stream, ~0.5 solar for a southern IVC, and ~ solar for two northern IVCs (the IV Arch and LLIV Arch). Finally, approximate values in the range 0.5-2 solar are found for three more IVCs. 2) Depletion patterns in IVCs are like those in warm disk or halo gas. 3) Most distance limits are based on strong UV lines of CII, SiII and MgII, a few on CaII. Distance limits for major HVCs are >5 kpc, while distance brackets for several IVCs are in the range 0.5-2 kpc. 4) Mass limits for major IVCs are 0.5-8x10^5 M_sun, but for major HVCs they are >10^6 M_sun. 5) The CaII/HI ratio varies by up to a factor 2-5 within a single cloud, somewhat more between clouds. 6) The NaIHI ratio varies by a factor >10 within a cloud, and even more between clouds. Thus, CaII can be useful for determining both lower and upper distance limits, but NaI only yields upper limits.

  8. Late-Quaternary Variations in Tree Cover at the Northern Forest-Tundra Ecotone

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    and contemporary observations of woody cover from the Advanced Very High Resolution Radiometer (AVHRR) sensor. Our about land-use and land-cover change [DeFries, 2008]. The widespread availability, low cost, and high. Biogeophysical feedbacks, involving exchanges of water and energy between the land surface and atmosphere [Bonan

  9. Ice Cover on the Great Lakes NATIONALOCEANIC

    E-Print Network [OSTI]

    Ice Cover on the Great Lakes NATIONALOCEANIC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM ER CE Great Lakes Ice Cover facts since 1973 - 94.7% ice coverage in 1979 is the maximum on record - 9.5% ice coverage in 2002 is the lowest on record - 11.5% ice coverage in 1998, a strong El Nino

  10. THREE-DIMENSIONAL CLOUD STRUCTURE OBSERVED DURING DOE ARM'S 2009 CLOUD TOMOGRAPHY FIELD EXPERIMENT

    E-Print Network [OSTI]

    vapor. During the Summer of 2009, five scanning microwave radiometers were deployed along an eight conditions. The high-resolution tomographic retrievals provide a unique opportunity for investigating Associates, LLC under Contract No. DE-AC02- 98CH10886 with the U.S. Department of Energy. The publisher

  11. Using Radar, Lidar and Radiometer Data from NSA and SHEBA to Quantify Cloud Property Effects on the Surface Heat Budget in the Arctic

    SciTech Connect (OSTI)

    Janet Intrieri; Mathhew Shupe

    2005-01-01T23:59:59.000Z

    Cloud and radiation data from two distinctly different Arctic areas are analyzed to study the differences between coastal Alaskan and open Arctic Ocean region clouds and their respective influence on the surface radiation budget. The cloud and radiation datasets were obtained from (1) the DOE North Slope of Alaska (NSA) facility in the coastal town of Barrow, Alaska, and (2) the SHEBA field program, which was conducted from an icebreaker frozen in, and drifting with, the sea-ice for one year in the Western Arctic Ocean. Radar, lidar, radiometer, and sounding measurements from both locations were used to produce annual cycles of cloud occurrence and height, atmospheric temperature and humidity, surface longwave and shortwave broadband fluxes, surface albedo, and cloud radiative forcing. In general, both regions revealed a similar annual trend of cloud occurrence fraction with minimum values in winter (60-75%) and maximum values during spring, summer and fall (80-90%). However, the annual average cloud occurrence fraction for SHEBA (76%) was lower than the 6-year average cloud occurrence at NSA (92%). Both Arctic areas also showed similar annual cycle trends of cloud forcing with clouds warming the surface through most of the year and a period of surface cooling during the summer, when cloud shading effects overwhelm cloud greenhouse effects. The greatest difference between the two regions was observed in the magnitude of the cloud cooling effect (i.e., shortwave cloud forcing), which was significantly stronger at NSA and lasted for a longer period of time than at SHEBA. This is predominantly due to the longer and stronger melt season at NSA (i.e., albedo values that are much lower coupled with Sun angles that are somewhat higher) than the melt season observed over the ice pack at SHEBA. Longwave cloud forcing values were comparable between the two sites indicating a general similarity in cloudiness and atmospheric temperature and humidity structure between the two regions.

  12. Cloud Seeding By: Julie Walter

    E-Print Network [OSTI]

    Toohey, Darin W.

    , smoke, that then are cooled because of the high altitudes. As the water or condensation nuclei cool more pushed up enough the warm air that is filled with moisture should reach an optimum cooling point-based Western Weather Consultants, whose company supplied Vail Resorts with the cloud seeding generators

  13. Cloud and Autonomic Computing Center

    E-Print Network [OSTI]

    Gelfond, Michael

    boundary layers and wind turbine aerodynamics Siva Parameswarn, Ph.D. Professor in the Department vehicles » Wake development behind wind turbines PHYSICS Ismael Regis de Farias Jr., Ph.D. Associate in cloud environments » Intelligent data management & understanding » Automated web service composition

  14. Clouds are integral to the climate system. They are a crucial component of the global water cycle, vital

    E-Print Network [OSTI]

    Allan, Richard P.

    gives a value of 61.6% cloud cover over the period January 2001 to December 2010). These estimates were with the Earth's radiative energy balance. They cool the surface by shading it from the direct solar beam but almost as strongly enhance the greenhouse effect of the atmosphere by reducing the efficiency by which

  15. Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud II: A Parameter Study

    E-Print Network [OSTI]

    Takahiro Kudoh; Shantanu Basu

    2006-01-04T23:59:59.000Z

    We use numerical simulations to study the effect of nonlinear MHD waves in a stratified, self-gravitating molecular cloud that is bounded by a hot and tenuous external medium. In a previous paper, we had shown the details of a standard model and studied the effect of varying the dimensionless amplitude. In this paper, we present the results of varying two other important free parameters: beta_0, the initial ratio of gas to magnetic pressure at the cloud midplane, and the dimensionless frequency of driving. Furthermore, we present the case of a temporally random driving force. Our results demonstrate that a very important consideration for the actual level of turbulent support against gravity is the ratio of driving wavelength lambda_0 to the the size of the initial non-turbulent cloud; maximum cloud expansion is achieved when this ratio is close to unity. The best consistency with the observational correlation of magnetic field strength, turbulent line width, and density is achieved by cloud models with beta_0 approx 1. We also calculate the spatial power spectra of the turbulent clouds, and show that significant power is developed on scales larger than the scale length H_0 of the initial cloud, even if the input wavelength of turbulence lambda_0 approx H_0. The cloud stratification and resulting increase of Alfven speed toward the cloud edge allows for a transfer of energy to wavelengths significantly larger than lambda_0. This explains why the relevant time scale for turbulent dissipation is the crossing time over the cloud scale rather than the crossing time over the driving scale.

  16. Why do Particle Clouds Generate Electric Charges?

    E-Print Network [OSTI]

    T. Pähtz; H. J. Herrmann; T. Shinbrot

    2015-03-16T23:59:59.000Z

    Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment.

  17. Simulating mixed-phase Arctic stratus clouds: Sensitivity to ice initiationmechanisms

    SciTech Connect (OSTI)

    Sednev, I.; Menon, S.; McFarquhar, G.

    2009-04-10T23:59:59.000Z

    The importance of Arctic mixed-phase clouds on radiation and the Arctic climate is well known. However, the development of mixed-phase cloud parameterization for use in large scale models is limited by lack of both related observations and numerical studies using multidimensional models with advanced microphysics that provide the basis for understanding the relative importance of different microphysical processes that take place in mixed-phase clouds. To improve the representation of mixed-phase cloud processes in the GISS GCM we use the GISS single-column model coupled to a bin resolved microphysics (BRM) scheme that was specially designed to simulate mixed-phase clouds and aerosol-cloud interactions. Using this model with the microphysical measurements obtained from the DOE ARM Mixed-Phase Arctic Cloud Experiment (MPACE) campaign in October 2004 at the North Slope of Alaska, we investigate the effect of ice initiation processes and Bergeron-Findeisen process (BFP) on glaciation time and longevity of single-layer stratiform mixed-phase clouds. We focus on observations taken during October 9th-10th, which indicated the presence of a single-layer mixed-phase clouds. We performed several sets of 12-hour simulations to examine model sensitivity to different ice initiation mechanisms and evaluate model output (hydrometeors concentrations, contents, effective radii, precipitation fluxes, and radar reflectivity) against measurements from the MPACE Intensive Observing Period. Overall, the model qualitatively simulates ice crystal concentration and hydrometeors content, but it fails to predict quantitatively the effective radii of ice particles and their vertical profiles. In particular, the ice effective radii are overestimated by at least 50%. However, using the same definition as used for observations, the effective radii simulated and that observed were more comparable. We find that for the single-layer stratiform mixed-phase clouds simulated, process of ice phase initiation due to freezing of supercooled water in both saturated and subsaturated (w.r.t. water) environments is as important as primary ice crystal origination from water vapor. We also find that the BFP is a process mainly responsible for the rates of glaciation of simulated clouds. These glaciation rates cannot be adequately represented by a water-ice saturation adjustment scheme that only depends on temperature and liquid and solid hydrometeors contents as is widely used in bulk microphysics schemes and are better represented by processes that also account for supersaturation changes as the hydrometeors grow.

  18. Simulating mixed-phase Arctic stratus clouds: sensitivity to ice initiation mechanisms

    SciTech Connect (OSTI)

    Sednev, Igor; Sednev, I.; Menon, S.; McFarquhar, G.

    2008-02-18T23:59:59.000Z

    The importance of Arctic mixed-phase clouds on radiation and the Arctic climate is well known. However, the development of mixed-phase cloud parameterization for use in large scale models is limited by lack of both related observations and numerical studies using multidimensional models with advanced microphysics that provide the basis for understanding the relative importance of different microphysical processes that take place in mixed-phase clouds. To improve the representation of mixed-phase cloud processes in the GISS GCM we use the GISS single-column model coupled to a bin resolved microphysics (BRM) scheme that was specially designed to simulate mixed-phase clouds and aerosol-cloud interactions. Using this model with the microphysical measurements obtained from the DOE ARM Mixed-Phase Arctic Cloud Experiment (MPACE) campaign in October 2004 at the North Slope of Alaska, we investigate the effect of ice initiation processes and Bergeron-Findeisen process (BFP) on glaciation time and longevity of single-layer stratiform mixed-phase clouds. We focus on observations taken during 9th-10th October, which indicated the presence of a single-layer mixed-phase clouds. We performed several sets of 12-h simulations to examine model sensitivity to different ice initiation mechanisms and evaluate model output (hydrometeors concentrations, contents, effective radii, precipitation fluxes, and radar reflectivity) against measurements from the MPACE Intensive Observing Period. Overall, the model qualitatively simulates ice crystal concentration and hydrometeors content, but it fails to predict quantitatively the effective radii of ice particles and their vertical profiles. In particular, the ice effective radii are overestimated by at least 50%. However, using the same definition as used for observations, the effective radii simulated and that observed were more comparable. We find that for the single-layer stratiform mixed-phase clouds simulated, process of ice phase initiation due to freezing of supercooled water in both saturated and undersaturated (w.r.t. water) environments is as important as primary ice crystal origination from water vapor. We also find that the BFP is a process mainly responsible for the rates of glaciation of simulated clouds. These glaciation rates cannot be adequately represented by a water-ice saturation adjustment scheme that only depends on temperature and liquid and solid hydrometeors contents as is widely used in bulk microphysics schemes and are better represented by processes that also account for supersaturation changes as the hydrometeors grow.

  19. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-10T23:59:59.000Z

    The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available.

  20. Cloud speed impact on solar variability scaling â?? Application to the wavelet variability model

    E-Print Network [OSTI]

    Lave, Matthew; Kleissl, Jan

    2013-01-01T23:59:59.000Z

    Kleissl, J. , 2013. Deriving cloud velocity from an array ofCloud Speed Impact on Solar Variability Scaling -this work, we determine from cloud speeds. Cloud simulator

  1. Coherent flash of light emitted by a cold atomic cloud

    SciTech Connect (OSTI)

    Chalony, M. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Pierrat, R. [Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, F-75005 Paris (France); Delande, D. [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Wilkowski, D. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore)

    2011-07-15T23:59:59.000Z

    When a resonant laser sent on an optically thick cold atomic cloud is abruptly switched off, a coherent flash of light is emitted in the forward direction. This transient phenomenon is observed due to the highly resonant character of the atomic scatterers. We analyze quantitatively its temporal properties and show very good agreement with theoretical predictions. Based on complementary experiments, the phase of the coherent field is reconstructed without interferometric tools.

  2. Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos

    E-Print Network [OSTI]

    J. E. G. Peek; M. E. Putman; Jesper Sommer-Larsen

    2007-09-11T23:59:59.000Z

    Ongoing accretion onto galactic disks has been recently theorized to progress via the unstable cooling of the baryonic halo into condensed clouds. These clouds have been identified as analogous to the High-Velocity Clouds (HVCs) observed in HI in our Galaxy. Here we compare the distribution of HVCs observed around our own Galaxy and extra-planar gas around the Andromeda galaxy to these possible HVC analogs in a simulation of galaxy formation that naturally generates these condensed clouds. We find a very good correspondence between these observations and the simulation, in terms of number, angular size, velocity distribution, overall flux and flux distribution of the clouds. We show that condensed cloud accretion only accounts for ~ 0.2 M_solar / year of the current overall Galactic accretion in the simulations. We also find that the simulated halo clouds accelerate and become more massive as they fall toward the disk. The parameter space of the simulated clouds is consistent with all of the observed HVC complexes that have distance constraints, except the Magellanic Stream which is known to have a different origin. We also find that nearly half of these simulated halo clouds would be indistinguishable from lower-velocity gas and that this effect is strongest further from the disk of the galaxy, thus indicating a possible missing population of HVCs. These results indicate that the majority of HVCs are consistent with being infalling, condensed clouds that are a remnant of Galaxy formation.

  3. Features . . . Cover Crop Value to Cotton

    E-Print Network [OSTI]

    Watson, Craig A.

    .............................................................................................Page 6 Fuel Prices Projections - Encouraging News .......................Page 7 Agronomy Notes VolumeFeatures . . . Cotton Cover Crop Value to Cotton Cotton Price and Rotation ..............................................................Page 5 Miscellaneous Large differences in nitrogen prices.......................................Page 6

  4. The VMC Survey - XIV. First results on the look-back time star-formation rate tomography of the Small Magellanic Cloud

    E-Print Network [OSTI]

    Rubele, Stefano; Kerber, Leandro; Cioni, Maria-Rosa L; Piatti, Andres E; Zaggia, Simone; Bekki, Kenji; Bressan, Alessandro; Clementini, Gisella; de Grijs, Richard; Emerson, Jim P; Groenewegen, Martin A T; Ivanov, Valentin D; Marconi, Marcella; Marigo, Paola; Moretti, Maria-Ida; Ripepi, Vincenzo; Subramanian, Smitha; Tatton, Benjamin L; van Loon, Jacco Th

    2015-01-01T23:59:59.000Z

    We analyse deep images from the VISTA survey of the Magellanic Clouds in the YJKs filters, covering 14 sqrdeg (10 tiles), split into 120 subregions, and comprising the main body and Wing of the Small Magellanic Cloud (SMC). We apply a colour--magnitude diagram reconstruction method that returns their best-fitting star formation rate SFR(t), age-metallicity relation (AMR), distance and mean reddening, together with 68% confidence intervals. The distance data can be approximated by a plane tilted in the East-West direction with a mean inclination of 39 deg, although deviations of up to 3 kpc suggest a distorted and warped disk. After assigning to every observed star a probability of belonging to a given age-metallicity interval, we build high-resolution population maps. These dramatically reveal the flocculent nature of the young star-forming regions and the nearly smooth features traced by older stellar generations. They document the formation of the SMC Wing at ages <0.2 Gyr and the peak of star formation ...

  5. High-resolution imaging of compact high-velocity clouds

    E-Print Network [OSTI]

    Robert Braun; Butler Burton

    1999-12-20T23:59:59.000Z

    Six examples of the compact, isolated high-velocity HI clouds (CHVCs) identified by Braun and Burton (1999) have been imaged with the WSRT. The 65 confirmed objects in this class define a dynamically cold system, with a global minimum for the velocity dispersion of only 70 km/s, found in the Local Group Standard of Rest, while in-falling at 100 km/s toward the LG barycenter. These objects have a characteristic morphology, in which several compact cores are embedded in a diffuse halo. The compact cores typically account for 40% of the HI line flux while covering some 15% of the source area. The cores are the cool condensed phase of HI, the CNM, with temp. near 100 K, while the halos appear to be a shielding column of warm diffuse HI, the WNM, with temp. near 8000 K. We detect a core with one of the narrowest HI emission lines ever observed, with intrinsic FWHM of 2 km/s and 75 K brightness. From a comparison of column and volume densities we derive a distance in the range 0.5 to 1 Mpc. We determine a metallicity for this same object of 0.04 to 0.07 solar. Comparably high distances are implied by demanding the stability of objects with multiple cores, which show relative velocities as large as 70 km/s on 30 arcmin scales. Many compact cores show systematic velocity gradients along the major axis of their elliptical extent which are consistent with circular rotation. Several of the derived rotation curves are well-fit by Navarro, Frenk, and White (1997) cold dark matter profiles. These kinematic signatures imply a high dark-to-visible mass ratio of 10-50, for D=0.7Mpc, which scales as 1/D. The implied dark matter halos dominate the mass volume density within the central 2 kpc (10 arcmin) of each source, providing a sufficent hydrostatic pressure to allow local CNM condensation. (abridged)

  6. Long-term Observations of the Convective Boundary Layer Using Insect Radar Returns at the SGP ARM Climate Research Facility

    SciTech Connect (OSTI)

    Chandra, A S; Kollias, P; Giangrande, S E; Klein, S A

    2009-08-20T23:59:59.000Z

    A long-term study of the turbulent structure of the convective boundary layer (CBL) at the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) Climate Research Facility is presented. Doppler velocity measurements from insects occupying the lowest 2 km of the boundary layer during summer months are used to map the vertical velocity component in the CBL. The observations cover four summer periods (2004-08) and are classified into cloudy and clear boundary layer conditions. Profiles of vertical velocity variance, skewness, and mass flux are estimated to study the daytime evolution of the convective boundary layer during these conditions. A conditional sampling method is applied to the original Doppler velocity dataset to extract coherent vertical velocity structures and to examine plume dimension and contribution to the turbulent transport. Overall, the derived turbulent statistics are consistent with previous aircraft and lidar observations. The observations provide unique insight into the daytime evolution of the convective boundary layer and the role of increased cloudiness in the turbulent budget of the subcloud layer. Coherent structures (plumes-thermals) are found to be responsible for more than 80% of the total turbulent transport resolved by the cloud radar system. The extended dataset is suitable for evaluating boundary layer parameterizations and testing large-eddy simulations (LESs) for a variety of surface and cloud conditions.

  7. 6, 55435583, 2006 Aerosol nucleation

    E-Print Network [OSTI]

    Boyer, Edmond

    and cloud cover via the second indirect aerosol effect that would explain observed variations in global cloud cover. We esti- mate that the variation in radiative forcing resulting from a response of clouds

  8. A Novel Retrieval Algorithm for Cloud Optical Properties from the Atmopsheric Radiation Measurement Program's Two-Channel Narrow-Field-of-View Radiometer

    SciTech Connect (OSTI)

    Wiscombe, Warren J.; Marshak, A.; Chiu, J.-Y. C.; Knyazikhin, Y.; Barnard, James C.; Luo, Yi

    2005-03-14T23:59:59.000Z

    Cloud optical depth is the most important of all cloud optical properties, and vital for any cloud-radiation parameterization. To estimate cloud optical depth, the atmospheric science community has widely used ground-based flux measurements from either broadband or narrowband radiometers in the past decade. However, this type of technique is limited to overcast conditions and, at best, gives us an "effective" cloud optical depth instead of its "local" value. Unlike flux observations, monochromatic narrow-field-of-view (NFOV) radiance measurements contain information of local cloud properties, but unfortunately, the use of radiance to interpret optical depth suffers from retrieval ambiguity. We have pioneered an algorithm to retrieve cloud optical depth in a fully three-dimensional cloud situation using new Atmospheric Radiation Measurement (ARM) ground-based passive two-channel (673 and 870 nm) NFOV measurements. The underlying principle of the algorithm is that these two channels have similar cloud properties but strong spectral contrast in surface reflectance. This algorthm offers the first opportunity to illustrate cloud evolution with high temporal resolution retrievals. A combination of two-channel NFOV radiances with multi-filter rotating shadowband radiometer (MFRSR) fluxes for the retrieval of cloud optical properties is also discussed.

  9. UNDERSTANDING TRENDS ASSOCIATED WITH CLOUDS IN IRRADIATED EXOPLANETS

    SciTech Connect (OSTI)

    Heng, Kevin [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Demory, Brice-Olivier, E-mail: kevin.heng@csh.unibe.ch, E-mail: demory@mit.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2013-11-10T23:59:59.000Z

    Unlike previously explored relationships between the properties of hot Jovian atmospheres, the geometric albedo and the incident stellar flux do not exhibit a clear correlation, as revealed by our re-analysis of Q0-Q14 Kepler data. If the albedo is primarily associated with the presence of clouds in these irradiated atmospheres, a holistic modeling approach needs to relate the following properties: the strength of stellar irradiation (and hence the strength and depth of atmospheric circulation), the geometric albedo (which controls both the fraction of starlight absorbed and the pressure level at which it is predominantly absorbed), and the properties of the embedded cloud particles (which determine the albedo). The anticipated diversity in cloud properties renders any correlation between the geometric albedo and the stellar flux weak and characterized by considerable scatter. In the limit of vertically uniform populations of scatterers and absorbers, we use an analytical model and scaling relations to relate the temperature-pressure profile of an irradiated atmosphere and the photon deposition layer and to estimate whether a cloud particle will be lofted by atmospheric circulation. We derive an analytical formula for computing the albedo spectrum in terms of the cloud properties, which we compare to the measured albedo spectrum of HD 189733b by Evans et al. Furthermore, we show that whether an optical phase curve is flat or sinusoidal depends on whether the particles are small or large as defined by the Knudsen number. This may be an explanation for why Kepler-7b exhibits evidence for the longitudinal variation in abundance of condensates, while Kepler-12b shows no evidence for the presence of condensates despite the incident stellar flux being similar for both exoplanets. We include an 'observer's cookbook' for deciphering various scenarios associated with the optical phase curve, the peak offset of the infrared phase curve, and the geometric albedo.

  10. Determinating Timing Channels in Statistically Multiplexed Clouds

    E-Print Network [OSTI]

    Aviram, Amittai; Ford, Bryan; Gummadi, Ramakrishna

    2010-01-01T23:59:59.000Z

    Timing side-channels represent an insidious security challenge for cloud computing, because: (a) they enable one customer to steal information from another without leaving a trail or raising alarms; (b) only the cloud provider can feasibly detect and report such attacks, but the provider's incentives are not to; and (c) known general-purpose timing channel control methods undermine statistical resource sharing efficiency, and, with it, the cloud computing business model. We propose a new cloud architecture that uses provider-enforced deterministic execution to eliminate all timing channels internal to a shared cloud domain, without limiting internal resource sharing. A prototype determinism-enforcing hypervisor demonstrates that utilizing such a cloud might be both convenient and efficient. The hypervisor enables parallel guest processes and threads to interact via familiar shared memory and file system abstractions, and runs moderately coarse-grained parallel tasks as efficiently and scalably as current nond...

  11. New XMM-Newton observations of SNRs in the SMC

    E-Print Network [OSTI]

    Filipovic, M D; Winkler, P F; Pietsch, W; Payne, J L; Crawford, E J; De Horta, A Y; Stootman, F H; Reaser, B E

    2008-01-01T23:59:59.000Z

    A complete overview of the supernova remnant (SNR) population is required to investigate their evolution and interaction with the surrounding interstellar medium in the Small Magellanic Cloud (SMC). Recent XMM-Newton observations of the SMC cover three known SNRs (DEM S5, SNR B0050-72.8, and SNR B0058-71.8), which are poorly studied and are X-ray faint. We used new multi-frequency radio-continuum surveys and new optical observations at Ha, [SII], and [OIII] wavelengths, in combination with the X-ray data, to investigate their properties and to search for new SNRs in the SMC. We used X-ray source selection criteria and found one SMC object with typical SNR characteristics (HFPK 334), that was initially detected by ROSAT. We analysed the X-ray spectra and present multi-wavelength morphological studies of the three SNRs and the new candidate. Using a non-equilibrium ionisation collisional plasma model, we find temperatures kT around 0.18 keV for the three known remnants and 0.69 keV for the candidate. The low te...

  12. Fine-scale Horizontal Structure of Arctic Mixed-Phase Clouds.

    SciTech Connect (OSTI)

    Rambukkange,M.; Verlinde, J.; Elorante, E.; Luke, E.; Kollias, P.; Shupe, M.

    2006-07-10T23:59:59.000Z

    Recent in situ observations in stratiform clouds suggest that mixed phase regimes, here defined as limited cloud volumes containing both liquid and solid water, are constrained to narrow layers (order 100 m) separating all-liquid and fully glaciated volumes (Hallett and Viddaurre, 2005). The Department of Energy Atmospheric Radiation Measurement Program's (DOE-ARM, Ackerman and Stokes, 2003) North Slope of Alaska (NSA) ARM Climate Research Facility (ACRF) recently started collecting routine measurement of radar Doppler velocity power spectra from the Millimeter Cloud Radar (MMCR). Shupe et al. (2004) showed that Doppler spectra has potential to separate the contributions to the total reflectivity of the liquid and solid water in the radar volume, and thus to investigate further Hallett and Viddaurre's findings. The Mixed-Phase Arctic Cloud Experiment (MPACE) was conducted along the NSA to investigate the properties of Arctic mixed phase clouds (Verlinde et al., 2006). We present surface based remote sensing data from MPACE to discuss the fine-scale structure of the mixed-phase clouds observed during this experiment.

  13. Searching for Dark Matter Annihilation in the Smith High-Velocity Cloud

    E-Print Network [OSTI]

    Alex Drlica-Wagner; German A. Gomez-Vargas; John W. Hewitt; Tim Linden; Luigi Tibaldo

    2014-06-30T23:59:59.000Z

    Recent observations suggest that some high-velocity clouds may be confined by massive dark matter halos. In particular, the proximity and proposed dark matter content of the Smith Cloud make it a tempting target for the indirect detection of dark matter annihilation. We argue that the Smith Cloud may be a better target than some Milky Way dwarf spheroidal satellite galaxies and use gamma-ray observations from the Fermi Large Area Telescope to search for a dark matter annihilation signal. No significant gamma-ray excess is found coincident with the Smith Cloud, and we set strong limits on the dark matter annihilation cross section assuming a spatially-extended dark matter profile consistent with dynamical modeling of the Smith Cloud. Notably, these limits exclude the canonical thermal relic cross section ($\\sim 3\\times10^{-26}{\\rm cm}^{3}{\\rm s}^{-1}$) for dark matter masses $\\lesssim 30$ GeV annihilating via the $b \\bar b$ or $\\tau^{+}\\tau^{-}$ channels for certain assumptions of the dark matter density profile; however, uncertainties in the dark matter content of the Smith Cloud may significantly weaken these constraints.

  14. The Microbase Value-Added Product: A Baseline Retrieval of Cloud Microphysical Properties

    SciTech Connect (OSTI)

    Dunn, M; Johnson, K; Jensen, M

    2011-05-31T23:59:59.000Z

    This report describes the Atmospheric Radiation Measurement (ARM) Climate Research Facility baseline cloud microphysical properties (MICROBASE) value-added product (VAP). MICROBASE uses a combination of millimeter-wavelength cloud radar, microwave radiometer, and radiosonde observations to estimate the vertical profiles of the primary microphysical parameters of clouds including the liquid/ice water content and liquid/ice cloud particle effective radius. MICROBASE is a baseline algorithm designed to apply to most conditions and locations using a single set of parameterizations and a simple determination of water phase based on temperature. This document provides the user of this product with guidelines to assist in determining the accuracy of the product under certain conditions. Quality control flags are designed to identify outliers and indicate instances where the retrieval assumptions may not be met. The overall methodology is described in this report through a detailed description of the input variables, algorithms, and output products.

  15. Analysis of cloud layer structure in Shouxian, China using RS92 radiosonde aided by 95 GHz cloud radar

    E-Print Network [OSTI]

    Li, Zhanqing

    Analysis of cloud layer structure in Shouxian, China using RS92 radiosonde aided by 95 GHz cloud to analyze cloud vertical structure over this area by taking advantage of the first direct measurements of cloud vertical layers from the 95 GHz radar. Singlelayer, twolayer, and threelayer clouds account for 28

  16. In Proceedings of APSEC 2010 Cloud Workshop, Sydney, Australia, 30th An Analysis of The Cloud Computing Security Problem

    E-Print Network [OSTI]

    Grundy, John

    of The Cloud Computing Security Problem Mohamed Al Morsy, John Grundy and Ingo Müller Computer Science to adopt IT without upfront investment. Despite the potential gains achieved from the cloud computing solution. Keywords: cloud computing; cloud computing security; cloud computing security management. I

  17. April 12, 2014: The Era of Cloud Computing is coming Headline: The Era of Cloud Computing is coming

    E-Print Network [OSTI]

    Buyya, Rajkumar

    April 12, 2014: The Era of Cloud Computing is coming #12;Headline: The Era of Cloud Computing of Cloud Computing at a seminar in MANIT and RGPV on Saturday. Inset headline: This is the right time to build a career in Cloud Computing Article: Prof. Rajkumar Buyya gave guidance to students about Cloud

  18. After the definition of Cloud Computing ... What has NIST done in the Cloud space lately? What's next?

    E-Print Network [OSTI]

    After the definition of Cloud Computing ... What has NIST done in the Cloud space lately? What Publication SP 500-292: Cloud Computing Reference Architecture. This document takes the NIST definition of Cloud Computing a step further by expanding the definition into a logical representation of the cloud

  19. Generated using version 3.0 of the official AMS LATEX template Computing and Partitioning Cloud Feedbacks using Cloud1

    E-Print Network [OSTI]

    Hartmann, Dennis

    by adjusting the change in cloud radiative forcing for non-cloud22 related effects as in Soden et al. (2008 planet, the global and annual mean effect40 of clouds at the top of atmosphere (TOA) is to increase Feedbacks using Cloud1 Property Histograms.2 Part I: Cloud Radiative Kernels3 Mark D. Zelinka Department

  20. Influence of Cloud-Top Height and Geometric Thickness on a MODIS Infrared-Based Ice Cloud Retrieval

    E-Print Network [OSTI]

    Baum, Bryan A.

    of the net cloud radiative forc- ing of these clouds requires a global, diurnal climatology, which can most and temporal scales. In this study, the sensitivity of an infrared-based ice cloud retrieval to effective cloud temperature is investigated, with a focus on the effects of cloud-top height and geometric thickness

  1. Alternative Landfill Cover. Innovative Technology Summary Report

    SciTech Connect (OSTI)

    NONE

    2000-12-01T23:59:59.000Z

    The primary purpose of an engineered cover is to isolate the underlying waste. A key element to isolating the wastes from the environment, engineered covers should minimize or prevent water from infiltrating into the landfill and coming into contact with the waste, thereby minimizing leachate generation. The U.S. EPA construction guidelines for soil hydraulic barriers specify that the soil moisture content and compactive effort may be increased to ensure that the barrier achieves a specified permeability of 1 x 10{sup {minus}7} cm/sec. However, constructing a soil barrier with high moisture content makes the soil more difficult to work and increases the required compactive effort to achieve the specified density, ultimately increasing the construction cost of the barrier. Alternative landfill cover designs rely on soil physical properties, hydraulic characteristics, and vegetation requirements to lower the flux rate of water through the cover. They can achieve greater reliability than the prescriptive RCRA Subtitle C design, especially under arid or semi-arid environmental conditions. With an alternative cover design, compacted soil barriers can be constructed with a soil moisture content that makes placement and compaction of the soil easier and less expensive. Under these conditions, the soil barrier has more capacity to absorb and control moisture within it, thereby enhancing the reliability of the barrier. This document contains information on the above-mentioned technology, including description, applicability, cost, and performance, data.

  2. CHARACTERIZATION OF CLOUDS IN TITAN'S TROPICAL ATMOSPHERE

    SciTech Connect (OSTI)

    Griffith, Caitlin A.; Penteado, Paulo [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85719 (United States); Rodriguez, Sebastien [Laboratoire AIM, Universite Paris 7/CNRS/CEA-Saclay, DSM/IRFU/SAp (France); Le Mouelic, Stephane [Laboratoire de Planetologie et Geodynamique, CNRS, UMR-6112, Universite de Nantes, 44000 Nantes (France); Baines, Kevin H.; Buratti, Bonnie; Sotin, Christophe [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Clark, Roger [U.S. Geological Survey, Denver, CO 80225 (United States); Nicholson, Phil [Department of Astronomy, Cornell University, Ithaca, NY (United States); Jaumann, Ralf [Institute of Planetary Exploration, Deutsche Zentrum, fuer Luft- und Raumfahrt (Germany)

    2009-09-10T23:59:59.000Z

    Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere. Radiative transfer analyses indicate similarities between summer polar and tropical methane clouds. Like their southern counterparts, tropical clouds consist of particles exceeding 5 {mu}m. They display discrete structures suggestive of convective cumuli. They prevail at a specific latitude band between 8 deg. - 20 deg. S, indicative of a circulation origin and the beginning of a circulation turnover. Yet, unlike the high latitude clouds that often reach 45 km altitude, these discrete tropical clouds, so far, remain capped to altitudes below 26 km. Such low convective clouds are consistent with the highly stable atmospheric conditions measured at the Huygens landing site. Their characteristics suggest that Titan's tropical atmosphere has a dry climate unlike the south polar atmosphere, and despite the numerous washes that carve the tropical landscape.

  3. Dark Clouds on the Horizon: Using Cloud Storage as Attack Vector and Online Slack Space

    E-Print Network [OSTI]

    Dark Clouds on the Horizon: Using Cloud Storage as Attack Vector and Online Slack Space Martin this as online slack space. We conclude by discussing security improvements for mod- ern online storage services protocol. With the advent of cloud computing and the shared usage of resources, these centralized storage

  4. To Cloud or Not to Cloud: A Mobile Device Perspective on Energy Consumption of Applications

    E-Print Network [OSTI]

    Namboodiri, Vinod

    To Cloud or Not to Cloud: A Mobile Device Perspective on Energy Consumption of Applications Vinod important criteria might be the energy consumed by the applications they run. The goal of this work is to characterize under what scenarios cloud-based applications would be relatively more energy-efficient for users

  5. Aircraft Microphysical Documentation from Cloud Base to Anvils of Hailstorm Feeder Clouds in Argentina

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    in Argentina DANIEL ROSENFELD The Hebrew University of Jerusalem, Jerusalem, Israel WILLIAM L. WOODLEY Woodley, Argentina, with a cloud-physics jet aircraft penetrating the major feeder clouds from cloud base to the 45°C. Introduction The province of Mendoza in western Argentina (32°S, 68°W), which is known worldwide for its wine

  6. Investigating the Radiative Impact Clouds Using Retrieved Properties to Classify Cloud Type

    E-Print Network [OSTI]

    Hogan, Robin

    of Reading, RG6 6AL, UK Abstract. Active remote sensing allows cloud properties such as ice and liquid water remote sensing, Cloud categorization, Cloud properties, Radiative impact. PACS: 92.60. Vb. INTRODUCTION in a radiation scheme which can simulate the radiation budget and heating rates throughout the atmospheric

  7. The Design of a Community Science Cloud: The Open Science Data Cloud Perspective

    E-Print Network [OSTI]

    Grossman, Robert

    The Design of a Community Science Cloud: The Open Science Data Cloud Perspective Robert L. Grossman, Matthew Greenway, Allison P. Heath, Ray Powell, Rafael D. Suarez, Walt Wells, and Kevin White University Abstract--In this paper we describe the design, and implemen- tation of the Open Science Data Cloud

  8. From Grid to private Clouds, to interClouds. Project Team

    E-Print Network [OSTI]

    Vialle, Stéphane

    24/10/2011 1 From Grid to private Clouds, to interClouds. AlGorille Project Team An overviewGorille INRIA Project Team October 21, 2011 I Premise of Grid ComputingI Premise of Grid Computing... From Grid to private Clouds, to inter

  9. A 3D STOCHASTIC CLOUD MODEL FOR INVESTIGATING THE RADIATIVE PROPERTIES OF INHOMOGENEOUS CIRRUS CLOUDS

    E-Print Network [OSTI]

    Hogan, Robin

    A 3D STOCHASTIC CLOUD MODEL FOR INVESTIGATING THE RADIATIVE PROPERTIES OF INHOMOGENEOUS CIRRUS, Berkshire, United Kingdom 1 INTRODUCTION The importance of ice clouds on the earth's radiation budget for quantifying this effect, and several such models exist for boundary layer clouds, such as those of Cahalan et

  10. Compact, Isolated High-Velocity Clouds

    E-Print Network [OSTI]

    W. B. Burton; R. Braun; V. de Heij

    2002-06-20T23:59:59.000Z

    We consider here the class of compact, isolated, high-velocity HI clouds, CHVCs, which are sharply bounded in angular extent down to a limiting column density of 1.5x10^18 cm^-2. We describe our automated search algorithm and it's application to the LDS north of dec= -28 deg. and the HIPASS data south of dec=0, resulting in an all--sky catalog numbering 246 CHVCs. We argue that these objects are more likely to represent a single phenomenon in a similar evolutionary state than would a sample which included any of the major HVC complexes. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densities, (4) the number distribution of angular sizes, and (5) the number distribution of line widths. We show that the spatial and kinematic deployments of the ensemble of CHVCs contain various clues regarding their characteristic distance. These clues are not compatible with a location of the ensemble within the Galaxy proper. The deployments resemble in several regards those of the Local Group galaxies. We describe a model testing the hypothesis that the CHVCs are a Local Group population. The agreement of the model with the data is judged by extracting the observables from simulations, in a manner consistent with the sensitivities of the observations and explicitly taking account of Galactic obscuration. We show that models in which the CHVCs are the HI counterparts of dark-matter halos evolving in the Local Group potential provide a good match to the observables, if account is taken of tidal and ram--pressure disruption, the consequences of obscuration due to Galactic HI and of differing sensitivities and selection effects pertaining to the surveys.

  11. Free-Floating HI Clouds in the M 81 Group

    E-Print Network [OSTI]

    Elias Brinks; Fabian Walter; Evan D. Skillman

    2007-08-21T23:59:59.000Z

    Recent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~1e5 Msol) HI clouds with no obvious optical counterparts. We have searched 10 fields in the M81 group totalling 2.2 square degree, both targeting known dwarf spheroidal galaxies and blank fields around the central triplet. Our observations show that the new population of low-mass HI clouds appears to be confined to a region toward the South-East of the central triplet (at distances of ~100 kpc from M 81). Possible explanations for these free-floating HI clouds are that they are related to the dSphs found to the South-East of M 81, that they belong to the galaxies of the M 81 triplet (equivalent to HVCs), that they are of primordial nature and provide fresh, unenriched material falling into the M 81 group, or that they are tidal debris from the 3-body interaction involving M 81-M 82-NGC 3077. Based on circumstantial evidence, we currently favour the latter explanation.

  12. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-27T23:59:59.000Z

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore »scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  13. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lu, Chunsong [Nanjing Univ. of Information Science and Technology (China). Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters; Chinese Acadamy of Sciences, Beijing (China); Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.; Liu, Yangang [Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.; Niu, Shengjie [Nanjing Univ. of Information Science and Technology (China). Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters; Endo, Satoshi [Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.

    2014-12-27T23:59:59.000Z

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  14. HCN ice in Titan's high-altitude southern polar cloud

    E-Print Network [OSTI]

    de Kok, Remco J; Maltagliati, Luca; Irwin, Patrick G J; Vinatier, Sandrine

    2014-01-01T23:59:59.000Z

    Titan's middle atmosphere is currently experiencing a rapid change of season after northern spring arrived in 2009. A large cloud was observed for the first time above Titan's southern pole in May 2012, at an altitude of 300 km. This altitude previously showed a temperature maximum and condensation was not expected for any of Titan's atmospheric gases. Here we show that this cloud is composed of micron-sized hydrogen cyanide (HCN) ice particles. The presence of HCN particles at this altitude, together with new temperature determinations from mid-infrared observations, indicate a very dramatic cooling of Titan's atmosphere inside the winter polar vortex in early 2012. Such a cooling is completely contrary to previously measured high-altitude warming in the polar vortex, and temperatures are a hundred degrees colder than predicted by circulation models. Besides elucidating the nature of Titan's mysterious polar cloud, these results thus show that post-equinox cooling at the winter pole is much more efficient th...

  15. Assessing Cloud Spatial and Vertical Distribution with Infrared Cloud Analyzer

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProductsAlternativeOperational Management »EnergyHubs | DepartmentCloud Spatial

  16. Coherent light transport in a cold Strontium cloud

    E-Print Network [OSTI]

    Y. Bibel; B. Klappauf; J. C. Bernard; D. Delande; G. Labeyrie; C. Miniatura; D. Wilkowski; R. Kaiser

    2002-02-05T23:59:59.000Z

    We study light coherent transport in the weak localization regime using magneto-optically cooled strontium atoms. The coherent backscattering cone is measured in the four polarization channels using light resonant with a J=0 to J=1 transition of the Strontium atom. We find an enhancement factor close to 2 in the helicity preserving channel, in agreement with theoretical predictions. This observation confirms the effect of internal structure as the key mechanism for the contrast reduction observed with an Rubidium cold cloud (see: Labeyrie et al., PRL 83, 5266 (1999)). Experimental results are in good agreement with Monte-Carlo simulations taking into account geometry effects.

  17. Shoring up Infrastructure Weaknesses with Hybrid Cloud Storage

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Shoring up Infrastructure Weaknesses with Hybrid Cloud Storage #12;2StorSimple White Pages: Shoring Up Infrastructure Weaknesses with Hybrid Cloud Storage Table of Contents The Hybrid Cloud Context for IT Managers ............................................................. 3 The Bottleneck of Managing Storage

  18. Satellite Remote Sensing of Mid-level Clouds

    E-Print Network [OSTI]

    Jin, Hongchun 1980-

    2012-11-07T23:59:59.000Z

    algorithm is evaluated using the CALIPSO cloud phase products for single-layer, heterogeneous, and multi-layer scenes. The AIRS phase algorithm has excellent performance (>90%) in detecting ice clouds compared to the CALIPSO ice clouds. It is capable...

  19. A cloud-assisted design for autonomous driving

    E-Print Network [OSTI]

    Suresh Kumar, Swarun

    This paper presents Carcel, a cloud-assisted system for autonomous driving. Carcel enables the cloud to have access to sensor data from autonomous vehicles as well as the roadside infrastructure. The cloud assists autonomous ...

  20. Aneka Cloud Application Platform and Its Integration with Windows Azure

    E-Print Network [OSTI]

    Melbourne, University of

    scheduling, and energy efficient resource utilization. The Aneka Cloud Application platform, together. Ltd., Melbourne, Victoria, Australia 2 Cloud Computing and Distributed Systems (CLOUDS) Laboratory, Department of Computer Science and Software Engineering, The University of Melbourne, Australia Abstract

  1. Fair-weather clouds hold dirty secret | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fair-weather clouds hold dirty secret Fair-weather clouds hold dirty secret Released: May 05, 2013 New study reveals particles that seed small-scale clouds over Oklahoma Air...

  2. E-Cloud Build-up in Grooved Chambers

    E-Print Network [OSTI]

    Venturini, Marco

    2007-01-01T23:59:59.000Z

    and F. Zimmermann, ”LC e-Cloud Activities at CERN”, talkal. , Simulations of the Electron Cloud for Vari- ous Con?E-CLOUD BUILD-UP IN GROOVED CHAMBERS ? M. Venturini † LBNL,

  3. Building Dynamic Computing Infrastructures over Distributed Clouds Pierre Riteau

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Building Dynamic Computing Infrastructures over Distributed Clouds Pierre Riteau University--The emergence of cloud computing infrastructures brings new ways to build and manage computing systems objectives. First, leveraging virtualization and cloud computing infrastruc- tures to build distributed large

  4. Modelling Cloud Computing Infrastructure Marianne Hickey and Maher Rahmouni,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modelling Cloud Computing Infrastructure Marianne Hickey and Maher Rahmouni, HP Labs, Long Down, and shared vocabularies. Keywords: Modelling, Cloud Computing, RDF, Ontology, Rules, Validation 1 Introduction There is currently a shift towards cloud computing, which changes the model of provision

  5. Consistent cloud computing storage as the basis for distributed applications

    E-Print Network [OSTI]

    Anderson, James William

    2011-01-01T23:59:59.000Z

    Messaging in Cloud Computing . . . . . . . . . .7 1.4Eucalyptus Open—Source Cloud—Computing System. In C'C&#http://www.eweek.com/c/a/Cloud-Computing/Amazons—Head—Start—

  6. Spatial motion of the Magellanic Clouds. Tidal models ruled out?

    E-Print Network [OSTI]

    Ruzicka, Adam; Palous, Jan

    2008-01-01T23:59:59.000Z

    Recently, Kallivayalil et al. derived new values of the proper motion for the Large and Small Magellanic Clouds (LMC and SMC, respectively). The spatial velocities of both Clouds are unexpectedly higher than their previous values resulting from agreement between the available theoretical models of the Magellanic System and the observations of neutral hydrogen (HI) associated with the LMC and the SMC. Such proper motion estimates are likely to be at odds with the scenarios for creation of the large-scale structures in the Magellanic System suggested so far. We investigated this hypothesis for the pure tidal models, as they were the first ones devised to explain the evolution of the Magellanic System, and the tidal stripping is intrinsically involved in every model assuming the gravitational interaction. The parameter space for the Milky Way (MW)-LMC-SMC interaction was analyzed by a robust search algorithm (genetic algorithm) combined with a fast restricted N-body model of the interaction. Our method extended ...

  7. Magnetic Fields and the Triaxiality of Molecular Cloud Cores

    E-Print Network [OSTI]

    Shantanu Basu

    2000-08-16T23:59:59.000Z

    We make the hypothesis that molecular cloud fragments are triaxial bodies with a large scale magnetic field oriented along the short axis. While consistent with theoretical expectations, this idea is supported by magnetic field strength data, which show strong evidence for flattening along the direction of the mean magnetic field. It is also consistent with early submillimeter polarization data, which show that the projected direction of the magnetic field is often slightly misaligned with the projected minor axis of a molecular cloud core, i.e., the offset angle $\\Psi$ is nonzero. We calculate distributions of $\\Psi$ for various triaxial bodies, when viewed from a random set of viewing angles. The highest viewing probability always corresponds to $\\Psi=0^{\\circ}$, but there is a finite probability of viewing all nonzero $\\Psi$, including even $\\Psi =90^{\\circ}$; the average offset typically falls in the range $10^{\\circ}-30^{\\circ}$ for triaxial bodies most likely to satisfy observational and theoretical constraints.

  8. A new survey of cool supergiants in the Magellanic Clouds

    E-Print Network [OSTI]

    González-Fernández, Carlos; Negueruela, Ignacio; Marco, Amparo

    2015-01-01T23:59:59.000Z

    In this study, we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership to the clouds. Around two hundred new RSGs have been detected, hinting at a yet to be observed large population. Using near and mid infrared photometry we study the brightness distribution of these stars, the onset of mass-loss and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid and near infrared photometry to improve the observat...

  9. SGP Cloud and Land Surface Interaction Campaign (CLASIC): Measurement Platforms

    SciTech Connect (OSTI)

    MA Miller; R Avissar; LK Berg; SA Edgerton; ML Fischer; TJ Jackson; B. Kustas; PJ Lamb; G McFarquhar; Q Min; B Schmid; MS Torn; DD Tuner

    2007-06-01T23:59:59.000Z

    The Cloud and Land Surface Interaction Campaign (CLASIC) will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of CLASIC includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the ACRF SGP site. Mesoscale and microscale structures will be sampled with a variety of aircraft, surface, and radar observations. An overview of the measurement platforms that will be used during the CLASIC are described in this report. The coordination of measurements, especially as it relates to aircraft flight plans, will be discussed in the CLASIC Implementation Plan.

  10. Fast and efficient transport of large ion clouds

    E-Print Network [OSTI]

    Kamsap, Marius Romuald; Champenois, Caroline; Guyomarc'H, Didier; Houssin, Marie; Knoop, Martina

    2015-01-01T23:59:59.000Z

    The manipulation of trapped charged particles by electric fields is an accurate, robust and reliable technique for many applications or experiments in high-precision spectroscopy. The transfer of the ion sample between multiple traps allows the use of a tailored environment in quantum information, cold chemistry, or frequency metrology experiments. In this article, we experimentally study the transport of ion clouds of up to 50 000 ions. The design of the trap makes ions very sensitive to any mismatch between the assumed electric potential and the actual local one. Nevertheless, we show that being fast (100 $\\mu$s to transfer over more than 20 mm) increases the transport efficiency to values higher than 90 %, even with a large number of ions. For clouds of less than 2000 ions, a 100 % transfer efficiency is observed.

  11. Covered Product Category: Light Fixtures (Luminaires)

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including luminaires, or light fixtures. The luminaires product category is very broad and covers a wide variety of lighting products. Both ENERGY STAR® and FEMP provide programmatic guidance for various types of luminaires. See table 2 for more information about which types of light fixtures are covered by which program (FEMP or ENERGY STAR). Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  12. Land Use and Land Cover Change

    SciTech Connect (OSTI)

    Brown, Daniel; Polsky, Colin; Bolstad, Paul V.; Brody, Samuel D.; Hulse, David; Kroh, Roger; Loveland, Thomas; Thomson, Allison M.

    2014-05-01T23:59:59.000Z

    A contribution to the 3rd National Climate Assessment report, discussing the following key messages: 1. Choices about land-use and land-cover patterns have affected and will continue to affect how vulnerable or resilient human communities and ecosystems are to the effects of climate change. 2. Land-use and land-cover changes affect local, regional, and global climate processes. 3. Individuals, organizations, and governments have the capacity to make land-use decisions to adapt to the effects of climate change. 4. Choices about land use and land management provide a means of reducing atmospheric greenhouse gas levels.

  13. On water ice formation in interstellar clouds

    E-Print Network [OSTI]

    Renaud Papoular

    2005-07-06T23:59:59.000Z

    A model is proposed for the formation of water ice mantles on grains in interstellar clouds. This occurs by direct accretion of monomers from the gas, be they formed by gas or surface reactions. The model predicts the existence of a threshold in interstellar light extinction, A(v), which is mainly determined by the adsorption energy of water molecules on the grain material; for hydrocarbon material, chemical simulation places this energy between 0.5 and 2 kcal/mole, which sets the visible exctinction threshold at a few magnitudes, as observed. Once the threshold is crossed, all available water molecules in the gas are quickly adsorbed, forming an ice mantle, because the grain cools down and the adsorption energy on ice is higher than on bare grain. The model also predicts that the thickness of the mantle, and, hence, the optical thickness at 3 mu, grow linearly with A(v), as observed, with a slope which depends upon the total amount of water in the gas. Chemical simulation was also used to determine the adsorption sites and energies of O and OH on hydrocarbons, and study the dynamics of formation of water molecules by surface reactions with gaseous H atoms, as well as their chances of sticking in situ.

  14. Astrophysics of Dust in Cold Clouds

    E-Print Network [OSTI]

    B. T. Draine

    2003-04-28T23:59:59.000Z

    Nine lectures reviewing the astrophysics of dust in interstellar clouds. Topics include: (1) Summary of observational evidence concerning interstellar dust: broadband extinction, scattering of starlight, polarization of starlight, spectroscopy of dust, IR and FIR emission, and depletions of grain-forming elements. (2) Optics of interstellar dust grains: dielectric functions of nonconducting and conducting materials, calculational techniques, formulae valid in the Rayleigh limit, Kramers-Kronig relations, microwave emission mechanisms, and X-ray scattering. (3) IR and FIR emission: heating of interstellar dust, including single-photon heating, and resulting IR emission spectrum. (4) Charging of dust grains: collisional charging, photoelectric emission, and resulting charge distribution functions. (5) Dynamics: gas drag, Lorentz force, forces due to anisotropic radiation, and resulting drift velocities. (6) Rotational dynamics: brownian rotation, suprathermal rotation, and effects of starlight torques. (7) Alignment of interstellar dust: observations and theories. (8) Evolution of the grain population: dust formation in outflows, grain growth in the ISM, photodesorption, and grain destruction in shock waves. (9) Effects of dust grains: photoelectric heating, H2 formation, ion recombination, coupling of gas to magnetic fields, and dust grains as indicators of magnetic field direction.

  15. The Giant Molecular Cloud Environments of Infrared Dark Clouds

    E-Print Network [OSTI]

    Hernandez, Audra K

    2015-01-01T23:59:59.000Z

    We study the GMC environments surrounding 10 IRDCs, based on 13CO molecular line emission from the Galactic Ring Survey. Using a range of physical scales, we measure the physical properties of the IRDCs and their surrounding molecular material extending out to radii, R, of 30pc. By comparing different methods for defining cloud boundaries and for deriving mass surface densities, Sigma, and velocity dispersions, sigma, we settled on a preferred "CE,tau,G" method of "Connected Extraction" in position-velocity space along with Gaussian fitting to opacity-corrected line profiles for velocity dispersion and mass estimation. We examine how cloud definition affects measurements of the magnitude and direction of line of sight velocity gradients and velocity dispersions, including the associated dependencies on size scale. CE,tau,G-defined IRDCs and GMCs show velocity gradient versus size relations that scale approximately as dv_0/ds~s^(-1/2) and velocity dispersion versus size relations sigma~s^(1/2), which are consi...

  16. Percutaneous Endoluminal Bypass of Iliac Aneurysms with a Covered Stent

    SciTech Connect (OSTI)

    Ruebben, Alexander; Tettoni, Serena; Muratore, Pierluigi; Rossato, Dennis; Savio, Daniele; Rabbia, Claudio [Radiologia del Pronto Soccorso, Servizio di Angioradiologia, Azienda Ospedaliera San Giovanni Battista, Corso Bramante 88, I-10126 Turin (Italy)

    1998-07-15T23:59:59.000Z

    To evaluate the feasibility of percutaneous treatment of iliac aneurysms, a covered stent was inserted in nine men suffering from common iliac artery aneurysms (six cases), external iliac aneurysms (one case), or pseudoaneurysms (two cases). Placement of the stent was successful in all patients. In one patient, an endoprosthesis thrombosed after 15 days, but was successfully treated by thrombolysis and additional stent placement. At the follow-up examinations (mean period 22 months) all stent-grafts had remained patent. No late leakage or stenosis was observed.

  17. Cover Image: The cover shows the crystal structure of the alanate NaAlH4,

    E-Print Network [OSTI]

    of materials, hydrogen "encapsulates" Al to form a hydrogen-rich anion, AlH4 -, whose structure resembles is encapsulated by metal ions, and the hydrogen density is correspondingly lower. In the cover image, the diameter) - p13 (top): The estimated power output from 10% efficient solar cells covering 1.7% of the land area

  18. Electron Cloud Effects in Accelerators

    SciTech Connect (OSTI)

    Furman, M.A.

    2012-11-30T23:59:59.000Z

    Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  19. ARM - Lesson Plans: Making Clouds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow, Alaska OutreachMaking Clouds Outreach Home

  20. Sandia Energy - Cloud Computing Services

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand RequirementsCoatings Initiated at PNNL's Sequim BayCaptureCloud Computing Services