Sample records for tropical mesoscale convective

  1. October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems

    E-Print Network [OSTI]

    Johnson, Richard H.

    October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems: Implications for the Problem of Cumulus Parameterization By Richard H. Johnson Department beneath the stratiform com- ponents of these systems (Houze, 1977; Zipser, 1977; Johnson and Kriete, 1982

  2. Passive microwave observations of mesoscale convective systems over the tropical Pacific Ocean

    E-Print Network [OSTI]

    McGaughey, Gary Rae

    1994-01-01T23:59:59.000Z

    This paper presents high resolution passive microwave measurements obtained in the western Pacific warm pool region. These measurements represent the first comprehensive observations of convection over the tropical oceans, and were obtained from...

  3. A numerical study of mesoscale convection in a rotating tropical atmosphere

    E-Print Network [OSTI]

    Fitzpatrick, Patrick James

    1992-01-01T23:59:59.000Z

    similar to the profile of a tropical disturbance. The meso-p forcing of convection consisted of' seven temperature perturbations con- fined below 2. 4 km at intervals of 8 km out to 60 km. The meso-9 forcing of convection comprised of a cosine thermal... perturbation field out to 75 km. Two different classes of simulations were performed. The first part explored how background vorticity affects convection generated by meso-7 and meso-9 forcing. The second part investigated how meso-9 forcing of convection...

  4. Application of the 85 GHz ice scattering signature to a global study of mesoscale convective systems

    E-Print Network [OSTI]

    Devlin, Karen Irene

    1995-01-01T23:59:59.000Z

    It has long been observed that tropical convection tends to cluster, organizing into multicellular mesoscale convective systems (MCS), In convective towers, updrafts on the order of 10 m s-I favor the formation of large, precipitation-sized ice...

  5. Vertical profiles of radar reflectivity of convective cells in tropical and mid-latitude mesoscale convective systems

    E-Print Network [OSTI]

    Lutz, Kurt Reed

    1992-01-01T23:59:59.000Z

    of the radar beam for the NCAR CP-3 and CP-4 Doppler radars and the NOAA/TOGA Doppler radar as a function of beamwidth 3 Maximum ref lectivity at selected heights and the range to the closest radar, at 4. 4 km, for the convective cells from the 10-11 June... Maximum ref lectivity at selected heights and the range to the NOAA/TOGA Doppler radar, at 3. 9 km, for the convective cells from the 2 December 1988 monsoon case 21 21 51 56 63 70 76 Table 8 As in Table 7, except for the convective cells from...

  6. Mesoscale convective complex vs. non-mesoscale convective complex thunderstorms: a comparison of selected meteorological variables

    E-Print Network [OSTI]

    Hoofard, Michael Eugene

    1986-01-01T23:59:59.000Z

    MESOSCALE CONVECTIVE CCMPLLX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis MICHAkL EUGENE JJOOFARD Submitted to the Graduate College of Texas AJkM University in partial... by MICHAEL EUGENE HOOFARD Approved as to style and content by: a ter . enry (Chairman of Committee) %~5 44 c5 c usan gur c (Member) ona . oc ing (Member) ames . cogg (Head of Department) August 1986 ABSTRACT Nesoscale Convective Complex vs. Non...

  7. Air-sea interaction at contrasting sites in the Eastern Tropical Pacific : mesoscale variability and atmospheric convection at 10įN

    E-Print Network [OSTI]

    Farrar, J. Thomas (John Thomas), 1976-

    2007-01-01T23:59:59.000Z

    The role of ocean dynamics in driving air-sea interaction is examined at two contrasting sites on 125įW in the eastern tropical Pacific Ocean using data from the Pan American Climate Study (PACS) field program. Analysis ...

  8. Momentum transport processes in the stratiform regions of mesoscale convective systems over the western Pacific warm pool

    E-Print Network [OSTI]

    Mechem, David B.; Chen, Shuyi S.; Houze, Robert A. Jr.

    2006-04-01T23:59:59.000Z

    Momentum transport by the stratiform components of mesoscale convective systems (MCSs) during the Tropical OceanĖGlobal Atmosphere Coupled OceanĖAtmosphere Response Experiment in December 1992 is investigated using a ...

  9. Convective cell development and propagation in a mesoscale convective complex

    E-Print Network [OSTI]

    Ahn, Yoo-Shin

    2012-06-07T23:59:59.000Z

    ~ , National Fisheries University of Pusan Chairman of Advisory Committee: Dr ~ Kennth CD Brundidge A case study was made of the mesoscale convective complex (MCC) which occurred over southern Oklahoma and northern Texas on 27 May 1981. This storm moved... in an east-southeasterly direction and during much of its lifetime was observable by radars at Oklahoma City, OK and Stephenville, TX. It was found that the direction of cell (VIP level 3 or more reflectivity) propagation was somewhat erratic...

  10. Cold domes over the warm pool: a study of the properties of cold domes produced by mesoscale convective systems during TOGA COARE

    E-Print Network [OSTI]

    Caesar, Kathy-Ann Lois

    1995-01-01T23:59:59.000Z

    Mesoscale convective systems (MCSs) are known to cool the subcloud layer by the introduction of penetrative downdrafts to the surface, resulting in the formation of cold domes (also known as cold pools). Five MCSs sampled during the Tropical Ocean...

  11. Evolution of moisture convergence in a mesoscale convective complex

    E-Print Network [OSTI]

    Bercherer, John Phillip

    1990-01-01T23:59:59.000Z

    Committee: Dr. Keuneth C. Brundidge Two separate Mesoscale Convective Complexes (MCCs) were investigated to determine if a characteristic surface moisture convergence (MC) signature existed on the mesoscale during their lifecycle. The first storm (Case 1... convergence, a bandpass filtering technique was utilized. It was found that MC could identify the general area of initial thunderstorm activity 2 h prior to its development for both cases. During the initial development stage of Case 1, advection...

  12. Observations of prolific transient luminous event production above a mesoscale convective system in Argentina during

    E-Print Network [OSTI]

    Thomas, Jeremy N.

    in Argentina during the Sprite2006 Campaign in Brazil F. T. S√£o Sabbas,1 M. J. Taylor,2 P.D. Pautet,2 M. Bailey convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil, J. Geophys. Res., 115, A

  13. The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems

    E-Print Network [OSTI]

    Restivo, Michael Edward

    1995-01-01T23:59:59.000Z

    suggested that the threshold of about 40 dBZ at the -10 C level for rapid cloud electrification found in New Mexico by Dye et al. (1989) could be valid for tropical convection as well. Orville and Henderson (1986), and Goodman and Christian (1993), have... along with small ice and supercooled liquid water for cloud electrification and lightning to occur. Since most oceanic VPRR drop off rapidly above the freezing level compared to continental VPRR, this would provide evidence that the updraft velocities...

  14. Parameterized Mesoscale Forcing Mechanisms for Initiating Numerically Simulated Isolated Multicellular Convection

    E-Print Network [OSTI]

    Doswell III, Charles A.

    Multicellular Convection ADRIAN M. LOFTUS* School of Meteorology, University of Oklahoma, Norman, Oklahoma DANIEL B. WEBER Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma CHARLES A. DOSWELL III Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma

  15. Evaluation of mesoscale convective systems in South America using multiple satellite products and an objectbased approach

    E-Print Network [OSTI]

    Ebert, Beth

    and an objectbased approach E. M. C. Demaria,1 D. A. Rodriguez,2 E. E. Ebert,3 P. Salio,4 F. Su,5 and J. B. Valdes1 to precipitation was mitigating the effect of the errors. Citation: Demaria, E. M. C., D. A. Rodriguez, E. E. Ebert, P. Salio, F. Su, and J. B. Valdes (2011), Evaluation of mesoscale convective systems in South

  16. Cloud-to-ground lightning characteristics of warm season Mesoscale Convection Systems in the Central United States: 1992-1993

    E-Print Network [OSTI]

    Hoeth, Brian Richard

    2012-06-07T23:59:59.000Z

    This study provides a detailed analysis of cloud-to-aphics. ground (CG) lightning flashes within individual Mesoscale Convective Systems (MCSs) that occurred in the Central United States during May-August of 1992 and 1993. Analysis of the CG...

  17. The evolution of total lightning and radar reflectivity characteristics of two mesoscale convective systems over Houston, Texas

    E-Print Network [OSTI]

    Hodapp, Charles Lee

    2009-05-15T23:59:59.000Z

    originated in the convective or transition regions. Both in-situ charging mechanisms created by the development of the mesoscale updraft and charge advection by the front-to-rear flow likely contribute to the increased electrification and lightning...

  18. Meso-scale eects of tropical deforestation in Amazonia: preparatory LBA modelling studies

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Meso-scale eects of tropical deforestation in Amazonia: preparatory LBA modelling studies A. J forest is good, above deforested areas (pasture) poor. The models' underestimate of the temperature Modelling studies with general circulation models have shown that large-scale deforestation of the Amazon

  19. Impact of Resolution on Simulation of Closed Mesoscale Cellular Convection Identified by Dynamically Guided Watershed Segmentation

    SciTech Connect (OSTI)

    Martini, Matus; Gustafson, William I.; Yang, Qing; Xiao, Heng

    2014-11-27T23:59:59.000Z

    Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus that forms in response to a balance between mesoscale dynamics and smaller scale processes such as cloud radiative cooling and microphysics. We use the Weather Research and Forecasting model with chemistry (WRF-Chem) and fully coupled cloud-aerosol interactions to simulate marine low clouds during the VOCALS-REx campaign over the southeast Pacific. A suite of experiments with 3- and 9-km grid spacing indicates resolution-dependent behavior. The simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we develop a new automated method, which uses a variation of the watershed segmentation technique that combines the detection of cloud boundaries with a test for coincident vertical velocity characteristics. This ensures that the detected cloud fields are dynamically consistent for closed MCC, the most common MCC type over the VOCALS-REx region. We demonstrate that the 3-km simulation is able to reproduce the scaling between horizontal cell size and boundary layer height seen in satellite observations. However, the 9-km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing invariant MCC horizontal scale for all simulated boundary layers depths. The results imply that climate models with grid spacing of roughly 3 km or smaller may be needed to properly simulate the MCC structure in the marine stratocumulus regions.

  20. On the effect of the steady-state approximation in time-space composite studies of mesoscale convective systems

    E-Print Network [OSTI]

    Mattison, Kevin Morgan

    1992-01-01T23:59:59.000Z

    ON THE EFFECT OF THE STRA 'Y-STATE APPROXIMATION IN TIME-SPACE COMPOSITE STUDIES OF MESOSCALE CONVECTIVE SYSTEMS A Thesis KEVIN MORGAN MATTISON Subnitted to the Office of Graduate Studies of Texas A&M University in partial fulfillnent... of the requirements for the degree of MASTER OF SCIENCE Decenber 1992 Major Subject: Meteorology ON THE EFFECT OF THE STEADY-STATE APPROXINATIOH IN TIME-SPACE COMPOSITE STUDIES OF NESOSCALE COHVECTIVE SYSTENS A Thesis KEVIN MORGAN NATTISOH Approved as to style...

  1. Impact of Convective Organization on the Response of Tropical Precipitation Extremes to Warming

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Impact of Convective Organization on the Response of Tropical Precipitation Extremes to Warming extremes to warming in organized convection is ex- amined using a cloud-resolving model. Vertical shear, the fractional increase of precipitation extremes is similar to that of surface water vapor, which

  2. Regional Contrast of Mesoscale Convective System Structure prior to and during Monsoon Onset across South America

    E-Print Network [OSTI]

    Nesbitt, Steve

    South America THOMAS M. RICKENBACH, ROSANA NIETO-FERREIRA, AND RICHARD P. BARNHILL* Department across tropical and subtropical South America. The approach is to contrast regional differences tropical South America has the characteristic summertime maximum of a monsoon climate (Kousky 1988; Horel

  3. Mesoscale environmental models accompanying convection in the Texas HIPLEX region / by Mark Edward Humbert

    E-Print Network [OSTI]

    Humbert, Mark Edward

    1980-01-01T23:59:59.000Z

    with convection is upward motion at all levels with a maximum value just prior to max1mum convect1ve intensity. Days without convection showed a cont1nual vertical turbulent m1xing of moisture from a shallow boundary layer to the 700 mb level. Lack... of 4 g kg 1 are observed. The moisture content increases at the 22 Post Big Spring Midland Robert Lee 4 500 mb cn 0 O m 8 L. cn 6 x 4 2 700 mb . . ~ ''. ~' . ~ / r 12 10 850 mb 15 18 21 00 03 Time (GNT hours) Fig. 9. Time profiles...

  4. Radar, satellite, and lightning characteristics of select mesoscale convective systems in Texas

    E-Print Network [OSTI]

    Toracinta, Ernest Richard

    1995-01-01T23:59:59.000Z

    , the observation of high negative flash counts coincident with convective cores having small reflectivity lapse rates in the mixed phase region is consistent with the presence of large ice particles aloft. Positive CG flashes were mostly located in low reflectivity...

  5. Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK AND WILLIAM R. COTTON

    E-Print Network [OSTI]

    AND WILLIAM R. COTTON Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado merge into a large, long-lived organized convective system (Cotton and Anthes 1989). Thus, forecasting

  6. Influence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep Convection

    E-Print Network [OSTI]

    Johnson, Richard H.

    -Service Aircraft (MOZAIC) project are analyzed in the vicinity of deep convective outflow to study the variationsInfluence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep upper-tropospheric temperature and humidity by the Mea- surement of Ozone and Water Vapor by Airbus In

  7. Vertical structure of tropical oceanic convective clouds and its relation to precipitation

    E-Print Network [OSTI]

    Hartmann, Dennis

    data are collocated with precipitation rates from the Advanced Microwave Scanning Radiometer (AMSR high tops that are nearly two km deeper than moderately raining or non- raining high clouds. Rain rate.1029/2007GL032811. 1. Introduction [2] Tropical convection plays an important role in the energy and moisture

  8. The effect of shear on heat budgets in a simulated Mesoscale Convective System

    E-Print Network [OSTI]

    Shaw, Justin David

    2000-01-01T23:59:59.000Z

    in the lowest 2.5 km varying from 10-25 m s?Ļ. A fourth simulation was conducted using the weak wind shear profile and incorporating ice microphysics. An analysis domain was produced every two hours for the northern and southern portions of the convective line...

  9. Layer inflow into precipitating convection over the western tropical Pacific

    E-Print Network [OSTI]

    Mechem, David B.; Houze, Robert A. Jr.; Chen, Shuyi S.

    2002-07-01T23:59:59.000Z

    and the relativecoarseness of the TOGA COARE soundings.The available input data from the mesoscale model consist of three wind components(u, v and w), temperature, pressure, water vapour, rain water, cloud water and cloudice. The last two quantities, by de? nition, have zero... by linear interpolation of the hourly supplied MM5 data, to the right-hand side of the u, v, w, temperature, pressure and water vapour equations in a narrowzone near the lateral boundaries. The forcing is strongest at the boundary and decreasesto a ? fth...

  10. 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.

  11. ARM - Field Campaign - Year of Tropical Convection (YOTC)

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    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcal Documentation(AVIRIS) ProductsAirborneOctober 11, 2011 [Facility News]JanuarygovCampaignsYear of Tropical

  12. A comparison of tropical mesoscale convective systems in El Nino and La Nina

    E-Print Network [OSTI]

    Zolman, Jody Lynn

    1999-01-01T23:59:59.000Z

    the two years tend to follow these patterns. There was a greater number of MCSs in the Central Pacific and East Pacific in the El Nino year and fewer MCSs in the Maritime Continent. The area distributions and median intensities of MCSs were found...

  13. Use of ARM observations and numerical models to determine radiative and latent heating profiles of mesoscale convective systems for general circulation models

    SciTech Connect (OSTI)

    Tao, Wei-Kuo; Houze, Robert, A., Jr.; Zeng, Xiping

    2013-03-14T23:59:59.000Z

    This three-year project, in cooperation with Professor Bob Houze at University of Washington, has been successfully finished as planned. Both ARM (the Atmospheric Radiation Measurement Program) data and cloud-resolving model (CRM) simulations were used to identify the water budgets of clouds observed in two international field campaigns. The research results achieved shed light on several key processes of clouds in climate change (or general circulation models), which are summarized below. 1. Revealed the effect of mineral dust on mesoscale convective systems (MCSs) Two international field campaigns near a desert and a tropical coast provided unique data to drive and evaluate CRM simulations, which are TWP-ICE (the Tropical Warm Pool International Cloud Experiment) and AMMA (the African Monsoon Multidisciplinary Analysis). Studies of the two campaign data were contrasted, revealing that much mineral dust can bring about large MCSs via ice nucleation and clouds. This result was reported as a PI presentation in the 3rd ASR Science Team meeting held in Arlington, Virginia in March 2012. A paper on the studies was published in the Journal of the Atmospheric Sciences (Zeng et al. 2013). 2. Identified the effect of convective downdrafts on ice crystal concentration Using the large-scale forcing data from TWP-ICE, ARM-SGP (the Southern Great Plains) and other field campaigns, Goddard CRM simulations were carried out in comparison with radar and satellite observations. The comparison between model and observations revealed that convective downdrafts could increase ice crystal concentration by up to three or four orders, which is a key to quantitatively represent the indirect effects of ice nuclei, a kind of aerosol, on clouds and radiation in the Tropics. This result was published in the Journal of the Atmospheric Sciences (Zeng et al. 2011) and summarized in the DOE/ASR Research Highlights Summaries (see http://www.arm.gov/science/highlights/RMjY5/view). 3. Used radar observations to evaluate model simulations In cooperation with Profs. Bob Houze at University of Washington and Steven Rutledge at Colorado State University, numerical model results were evaluated with observations from W- and C-band radars and CloudSat/TRMM satellites. These studies exhibited some shortcomings of current numerical models, such as too little of thin anvil clouds, directing the future improvement of cloud microphysics parameterization in CRMs. Two papers of Powell et al (2012) and Zeng et al. (2013), summarizing these studies, were published in the Journal of the Atmospheric Sciences. 4. Analyzed the water budgets of MCSs Using ARM data from TWP-ICE, ARM-SGP and other field campaigns, the Goddard CRM simulations were carried out to analyze the water budgets of clouds from TWP-ICE and AMMA. The simulations generated a set of datasets on clouds and radiation, which are available http://cloud.gsfc.nasa.gov/. The cloud datasets were available for modelers and other researchers aiming to improve the representation of cloud processes in multi-scale modeling frameworks, GCMs and climate models. Special datasets, such as 3D cloud distributions every six minutes for TWP-ICE, were requested and generated for ARM/ASR investigators. Data server records show that 86,206 datasets were downloaded by 120 users between April of 2010 and January of 2012. 5. MMF simulations The Goddard MMF (multi-scale modeling framework) has been improved by coupling with the Goddard Land Information System (LIS) and the Goddard Earth Observing System Model, Version 5 (GOES5). It has also been optimized on NASA HEC supercomputers and can be run over 4000 CPUs. The improved MMF with high horizontal resolution (1 x 1 degree) is currently being applied to cases covering 2005 and 2006. The results show that the spatial distribution pattern of precipitation rate is well simulated by the MMF through comparisons with satellite retrievals from the CMOPRH and GPCP data sets. In addition, the MMF results were compared with three reanalyses (MERRA, ERA-Interim and CFSR). Although the MMF tends

  14. Final Technical Report for "Radiative Heating Associated with Tropical Convective Cloud Systems: Its Importance at Meso and Global Scales"

    SciTech Connect (OSTI)

    Schumacher, Courtney

    2012-12-13T23:59:59.000Z

    Heating associated with tropical cloud systems drive the global circulation. The overall research objectives of this project were to i) further quantify and understand the importance of heating in tropical convective cloud systems with innovative observational techniques, and ii) use global models to determine the large-scale circulation response to variability in tropical heating profiles, including anvil and cirrus cloud radiative forcing. The innovative observational techniques used a diversity of radar systems to create a climatology of vertical velocities associated with the full tropical convective cloud spectrum along with a dissection of the of the total heating profile of tropical cloud systems into separate components (i.e., the latent, radiative, and eddy sensible heating). These properties were used to validate storm-scale and global climate models (GCMs) and were further used to force two different types of GCMs (one with and one without interactive physics). While radiative heating was shown to account for about 20% of the total heating and did not have a strong direct response on the global circulation, the indirect response was important via its impact on convection, esp. in how radiative heating impacts the tilt of heating associated with the Madden-Julian Oscillation (MJO), a phenomenon that accounts for most tropical intraseasonal variability. This work shows strong promise in determining the sensitivity of climate models and climate processes to heating variations associated with cloud systems.

  15. The QBO's influence on lightning production and deep convection in the tropics

    E-Print Network [OSTI]

    Hernandez, Celina Anne

    2009-05-15T23:59:59.000Z

    ) flash densities and ten years (1998-2007) of TRMM Precipitation Radar (PR) deep convective and stratiform rainfall and convective echo top heights are analyzed. The QBO can be linked to deep convection through two hypothesized mechanisms: 1) modulation...

  16. Convective-Scale Variations in the Inner-Core Rainbands of a Tropical Cyclone ANTHONY C. DIDLAKE JR. AND ROBERT A. HOUZE JR.

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    Convective-Scale Variations in the Inner-Core Rainbands of a Tropical Cyclone ANTHONY C. DIDLAKE JR secondary eyewall forms at a certain radius, subsidence occurring along its inner edge separates it from the primary eyewall. 1. Introduction Improving intensity forecasts of tropical cyclones al- most certainly

  17. Convective-scale variations in the inner-core rainbands of a tropical cyclone Submitted for publication in Journal of the Atmospheric Sciences

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    Convective-scale variations in the inner-core rainbands of a tropical cyclone Submitted inner edge separates it from the primary eyewall. #12;3 1. Introduction Improving intensity forecasts of tropical cyclones almost certainly requires a better understanding of the structure and dynamics

  18. Impact of Aerosols on Tropical Cyclones: An Investigation Using Convection-permitting Model Simulation

    SciTech Connect (OSTI)

    Hazra, Anupam; Mukhopadhyay, P.; Taraphdar, Sourav; Chen, J. P.; Cotton, William R.

    2013-07-16T23:59:59.000Z

    The role of aerosols effect on two tropical cyclones over Bay of Bengal are investigated using a convection permitting model with two-moment mixed-phase bulk cloud microphysics scheme. The simulation results show the role of aerosol on the microphysical and dynamical properties of cloud and bring out the change in efficiency of the clouds in producing precipitation. The tracks of the TCs are hardly affected by the changing aerosol types, but the intensity exhibits significant sensitivity due to the change in aerosol contribution. It is also clearly seen from the analyses that higher heating in the middle troposphere within the cyclone center is in response to latent heat release as a consequence of greater graupel formation. Greater heating in the middle level is particularly noticeable for the clean aerosol regime which causes enhanced divergence in the upper level which, in turn, forces the lower level convergence. As a result, the cleaner aerosol perturbation is more unstable within the cyclone core and produces a more intense cyclone as compared to other two perturbations of aerosol. All these studies show the robustness of the concept of TC weakening by storm ingestion of high concentrations of CCN. The consistency of these model results gives us confidence in stating there is a high probability that ingestion of high CCN concentrations in a TC will lead to weakening of the storm but has little impact on storm direction. Moreover, as pollution is increasing over the Indian sub-continent, this study suggests pollution may be weakening TCs over the Bay of Bengal.

  19. Equilibrium Tropical Cyclone Size in an Idealized State of Axisymmetric RadiativeĖConvective Equilibrium*

    E-Print Network [OSTI]

    Chavas, Daniel R.

    Tropical cyclone size remains an unsolved problem in tropical meteorology, yet size plays a significant role in modulating damage. This work employs the Bryan cloud model (CM1) to systematically explore the sensitivity of ...

  20. Convection?

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

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  1. A Test of the Simulation of Tropical Convective Cloudiness by a Cloud-Resolving Model MARIO A. LOPEZ, DENNIS L. HARTMANN, PETER N. BLOSSEY, ROBERT WOOD,

    E-Print Network [OSTI]

    Hartmann, Dennis

    un- certainties in projections of future climates (Bony et al. 2006; Solomon et al. 2007). Clouds solar radiation, although their effect on the net energy balance is often much less than with intense tropical convective systems are known to have long lifetimes and to cover large areas, accounting

  2. EQUILIBRIUM VS. ACTIVATION CONTROL OF LARGE-SCALE VARIATIONS OF TROPICAL DEEP CONVECTION

    E-Print Network [OSTI]

    Mapes, Brian

    convective cloud systems. This essay highlights the distinction between processes which supply moisture separations of the LSVDC problem are reviewed. Scale separation, though rigorous, is artificial, since net cloudiness, are exam- ined as examples. Lower boundary flux enhancements and deep lifting exert both

  3. RETRIEVAL OF HYDROMETEOR PROFILES IN TROPICAL CYCLONES AND CONVECTION BY A COMBINED

    E-Print Network [OSTI]

    Jiang, Haiyan

    to simulate the ice phase radiative transfer process more reasonably. Final optimal 's as well as the observed a significant influence on the energy and water budgets. The latent heat release in tropical cyclones provides of the circulation of the storm. Directly related to latent heating, ice water content (IWC) and liq

  4. Characteristics of Precipitating Convective Systems Accounting for the Summer Rainfall of Tropical and Subtropical South America

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    and Subtropical South America ULRIKE ROMATSCHKE AND ROBERT A. HOUZE JR. University of Washington, Seattle of the precipitating cloud systems that account for the summer rainfall of tropical and subtropical South America role in the meteorology, climatology, and hydrology of South America. They not only produce

  5. The kinematic and cloud-to-ground lightning structure of the 9-10, June 1998 Red River Mesoscale Convective System

    E-Print Network [OSTI]

    Santarpia, Joshua

    2001-01-01T23:59:59.000Z

    interest in using it to study severe weather. Mesoscale vortices that are often asso- ciated with severe storms such as supercells and bow echoes have been of particular interest. One of the first discussions of this type of circulation is from Brooks... radar echoes associated with a tornado indicating a cyclonic circulation. He likened the structure to that of a small-scale hurricane. Ray's (1976) dual-Doppler radar analysis of a supercell storm was the first to show a vortex pair and strong cy...

  6. Use of ARM observations and numerical models to determine radiative and latent heating profiles of mesoscale convective systems for general circulation models

    SciTech Connect (OSTI)

    Houze, Jr., Robert A. [University of Washington Dept. of Atmospheric Sciences

    2013-11-13T23:59:59.000Z

    We examined cloud radar data in monsoon climates, using cloud radars at Darwin in the Australian monsoon, on a ship in the Bay of Bengal in the South Asian monsoon, and at Niamey in the West African monsoon. We followed on with a more in-depth study of the continental MCSs over West Africa. We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the observed anvil clouds to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model at high resolution using six different ice-phase microphysical schemes. We carried out further simulations with a cloud-resolving model forced by sounding network budgets over the Niamey region and over the northern Australian region. We have devoted some of the effort of this project to examining how well satellite data can determine the global breadth of the anvil cloud measurements obtained at the ARM ground sites. We next considered whether satellite data could be objectively analyzed to so that their large global measurement sets can be systematically related to the ARM measurements. Further differences were detailed between the land and ocean MCS anvil clouds by examining the interior structure of the anvils with the satellite-detected the CloudSat Cloud Profiling Radar (CPR). The satellite survey of anvil clouds in the Indo-Pacific region was continued to determine the role of MCSs in producing the cloud pattern associated with the MJO.

  7. 12.811 Tropical Meteorology, Spring 2005

    E-Print Network [OSTI]

    Emanuel, Kerry

    This course describes the behavior and dynamics of the tropical troposphere, from the large-scale energy balance down to cumulus convection and tropical cyclones. Topics include: Radiative-convective equilibrium; the Hadley ...

  8. Development and testing of parameterizations for continental and tropical ice cloud microphysical and radiative properties in GCM and mesoscale models. Final report

    SciTech Connect (OSTI)

    Heymsfield, A.

    1997-09-01T23:59:59.000Z

    The overall purpose of this research was to exploit measurements in clouds sampled during several field programs, especially from experiments in tropical regions, in a four-component study to develop and validate cloud parameterizations for general circulation models, emphasizing ice clouds. The components were: (1) parameterization of basic properties of mid- and upper-tropospheric clouds, such as condensed water content, primarily with respect to cirrus from tropical areas; (2) the second component was to develop parameterizations which express cloud radiative properties in terms of basic cloud microphysical properties, dealing primarily with tropical oceanic cirrus clouds and continental thunderstorm anvils, but also including altocumulus clouds; (3) the third component was to validate the parameterizations through use of ground-based measurements calibrated using existing and planned in-situ measurements of cloud microphysical properties and bulk radiative properties, as well as time-resolved data collected over extended periods of time; (4) the fourth component was to implement the parameterizations in the National Center for Atmospheric Research (NCAR) community climate model (CCM) II or in the NOAA-GFDL model (by L. Donner GFDL) and to perform sensitivity studies.

  9. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 98, NO. D5, PAGES 8695-8711, MAY 20, 1993 The Radiative Budgets of a Tropical MesoscaleConvective System

    E-Print Network [OSTI]

    Stephens, Graeme L.

    . The value of this total heating is governedby both infrared and solar absorption. Vertical profiles of this heating show the dominance of infrared cooling near cloud top and infrared heating inside and near cloud base. The shortwave heating rate can also be as large as the infrared coolingnear the cloud top region

  10. Structure and evolution of a convective band MCS

    E-Print Network [OSTI]

    Valdes-Manzanilla, Arturo

    1995-01-01T23:59:59.000Z

    circulation of the Mesoscale Convective Complex apparently aided in the formation of new lines of convection behind the primary convective line of the system. This process was repeated twice in the storm life cycle and led to multiple bands of convection...

  11. 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.

  12. Hydration of the lower stratosphere by ice crystal geysers over land convective systems

    E-Print Network [OSTI]

    Khaykin, S.

    The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to Mesoscale Convective Systems (MCSs) during ...

  13. The multiple vortex nature of tropical cyclogenesis

    E-Print Network [OSTI]

    Sippel, Jason Allen

    2005-02-17T23:59:59.000Z

    cells and vortices are the respective source of PV production and building blocks for the meso-?-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking...

  14. The Generation of a Mesoscale Convective System from Mountain Convection

    E-Print Network [OSTI]

    Tucker, Donna F.; Crook, N. Andrew

    1999-06-01T23:59:59.000Z

    . Heights are contoured with solid lines every 60 gpm and absolute vorticity (31025) is analyzed in dashed lines every 5 s21. FIG. 2. Skew T-log p diagram for Denver sounding at 1200 UTC 21 Jun 1993. Full wind barb is 5 m s21. FIG. 3. 500-mb observed... relative humidity and winds for 1200 UTC 21 Jun 1993 over innermost grid region shown in Fig. 5. Relative humidity is contoured every 10%, with full wind barb representing 5 m s21. Denver County is the smallest county near the center of the map. This work...

  15. Technical Sessions Parameterization of Convective Clouds, Mesoscale Convective Systems,

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystallineForeign ObjectOUR8, 2013Battelle:TechnicalP. Daum L.

  16. Silicon Micromachined Dimensional Calibration Artifact for Mesoscale...

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

    Micromachined Dimensional Calibration Artifact for Mesoscale Measurement Machines 1 Silicon Micromachined Dimensional Calibration Artifact for Mesoscale Measurement Machines 2...

  17. Mesoscale hybrid calibration artifact

    DOE Patents [OSTI]

    Tran, Hy D. (Albuquerque, NM); Claudet, Andre A. (Albuquerque, NM); Oliver, Andrew D. (Waltham, MA)

    2010-09-07T23:59:59.000Z

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  18. Mesoscale Dynamics Spring Semester 2014

    E-Print Network [OSTI]

    ATS 735 Mesoscale Dynamics (3 cr) Spring Semester 2014 Instructor: Richard H. Johnson, Room ATS 305, certain topics in mesoscale dynamics may be emphasized more than others. Although basic concepts lectures on some of the topics. Several books that are relevant to the course are: Cloud Dynamics, 1993 (R

  19. Dusty gust fronts and their contributions to long-lived convection in West Africa/

    E-Print Network [OSTI]

    McGraw-Herdeg, Michael (Michael P.)

    2010-01-01T23:59:59.000Z

    To model and predict the behavior of West African storms and mesoscale convective systems (MCSs), we must understand the life cycle of gust fronts, which invariably accompany thunderstorms and often initiate them. In this ...

  20. ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243252 Mesoscale Barotropic Instability of Vortex Rossby

    E-Print Network [OSTI]

    Zhang, Da-Lin

    ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243¬≠252 Mesoscale Barotropic Instability of Vortex Rossby Waves in Tropical Cyclones ZHONG Wei1 ( √ć), LU Han-Cheng1 (√∂ ), and Da-Lin ZHANG2 1 Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101 2 Department

  1. Radiative Heating of the ISCCP Upper Level Cloud Regimes and its Impact on the Large-scale Tropical Circulation

    SciTech Connect (OSTI)

    Li, Wei; Schumacher, Courtney; McFarlane, Sally A.

    2013-01-31T23:59:59.000Z

    Radiative heating profiles of the International Satellite Cloud Climatology Project (ISCCP) cloud regimes (or weather states) were estimated by matching ISCCP observations with radiative properties derived from cloud radar and lidar measurements from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) sites at Manus, Papua New Guinea, and Darwin, Australia. Focus was placed on the ISCCP cloud regimes containing the majority of upper level clouds in the tropics, i.e., mesoscale convective systems (MCSs), deep cumulonimbus with cirrus, mixed shallow and deep convection, and thin cirrus. At upper levels, these regimes have average maximum cloud occurrences ranging from 30% to 55% near 12 km with variations depending on the location and cloud regime. The resulting radiative heating profiles have maxima of approximately 1 K/day near 12 km, with equal heating contributions from the longwave and shortwave components. Upper level minima occur near 15 km, with the MCS regime showing the strongest cooling of 0.2 K/day and the thin cirrus showing no cooling. The gradient of upper level heating ranges from 0.2 to 0.4 K/(day?km), with the most convectively active regimes (i.e., MCSs and deep cumulonimbus with cirrus) having the largest gradient. When the above heating profiles were applied to the 25-year ISCCP data set, the tropics-wide average profile has a radiative heating maximum of 0.45Kday-1 near 250 hPa. Column-integrated radiative heating of upper level cloud accounts for about 20% of the latent heating estimated by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). The ISCCP radiative heating of tropical upper level cloud only slightly modifies the response of an idealized primitive equation model forced with the tropics-wide TRMM PR latent heating, which suggests that the impact of upper level cloud is more important to large-scale tropical circulation variations because of convective feedbacks rather than direct forcing by the cloud radiative heating profiles. However, the height of the radiative heating maxima and gradient of the heating profiles are important to determine the sign and patterns of the horizontal circulation anomaly driven by radiative heating at upper levels.

  2. A Regional OceanAtmosphere Model for Eastern Pacific Climate: Toward Reducing Tropical Biases*

    E-Print Network [OSTI]

    Wang, Yuqing

    .5¬į) of the ROAM enables it to capture mesoscale features, such as tropical instability waves, Central American gap these asymmetric features despite a solar radia- tion forcing at the top of the atmosphere that is zonally uniform

  3. Acoustic Characterization of Mesoscale Objects

    SciTech Connect (OSTI)

    Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T

    2007-03-13T23:59:59.000Z

    This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.

  4. Junhong Wei and Fuqing Zhang, Pennsylvania State University Mesoscale Gravity Waves in Moist Baroclinic Jet-Front Systems

    E-Print Network [OSTI]

    Thompson, Anne

    with small amount of moisture, dry dynamic gravity wave modes continue to dominate. However, convective-permitting simulations with the Weather Research and Forecast (WRF) model are performed to study mesoscale gravity waves/negative), and 7-km dynamic tropopause (turquoise lines). Wave Identification Figure 3. Comparison of WP5 at 132 h

  5. Mesoscale Modeling Spring Semester 2014

    E-Print Network [OSTI]

    is to present the development of the basic equations used in mesoscale models, as well as the various methods Integrity: All students are subject to the policies regarding academic integrity found in Section 1://www.conflictresolution.colostate.edu/conduct-code). Other information on academic integrity can be found on the Learning@CSU website (http://learning.colostate.edu/integrity

  6. Total lightning observations of severe convection over North Texas

    E-Print Network [OSTI]

    McKinney, Christopher Michael

    2009-05-15T23:59:59.000Z

    Density GSD Gridded Source Density LDAR Lightning Detection and Ranging MCS Mesoscale Convective System MSI Mesocyclone Strength Index MxFED Maximum Flash Extent Density MxFIDT Maximum Flash Initiation Density Total MxGSD Maximum Gridded Source.......................................................................................... 1 1.2 Background ....................................................................................... 4 1.3 Thesis Objectives and Hypothesis...................................................... 19 2. DATA AND METHODOLOGY...

  7. Posters Mesoscale Simulations of Convective Systems with Data Assimilation During

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006PhotovoltaicSeptember 22, 2014SocietyJ. Dudhia51 Posters7

  8. Meso-scale machining capabilities and issues

    SciTech Connect (OSTI)

    BENAVIDES,GILBERT L.; ADAMS,DAVID P.; YANG,PIN

    2000-05-15T23:59:59.000Z

    Meso-scale manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. These processes can fabricate two and three-dimensional parts having micron size features in traditional materials such as stainless steels, rare earth magnets, ceramics, and glass. Meso-scale processes that are currently available include, focused ion beam sputtering, micro-milling, micro-turning, excimer laser ablation, femto-second laser ablation, and micro electro discharge machining. These meso-scale processes employ subtractive machining technologies (i.e., material removal), unlike LIGA, which is an additive meso-scale process. Meso-scale processes have different material capabilities and machining performance specifications. Machining performance specifications of interest include minimum feature size, feature tolerance, feature location accuracy, surface finish, and material removal rate. Sandia National Laboratories is developing meso-scale electro-mechanical components, which require meso-scale parts that move relative to one another. The meso-scale parts fabricated by subtractive meso-scale manufacturing processes have unique tribology issues because of the variety of materials and the surface conditions produced by the different meso-scale manufacturing processes.

  9. Reactor Engineering: Experimental Investigation of Alpha Convection

    SciTech Connect (OSTI)

    Usman, Shoaib

    2012-10-12T23:59:59.000Z

    Natural convection, Rayleigh-Bernard convection, Transient convection and Conduction convection transition.

  10. High-Resolution Modeling to Assess Tropical Cyclone Activity in Future Climate Regimes

    SciTech Connect (OSTI)

    Lackmann, Gary

    2013-06-10T23:59:59.000Z

    Applied research is proposed with the following objectives: (i) to determine the most likely level of tropical cyclone intensity and frequency in future climate regimes, (ii) to provide a quantitative measure of uncertainty in these predictions, and (iii) to improve understanding of the linkage between tropical cyclones and the planetary-scale circulation. Current mesoscale weather forecasting models, such as the Weather Research and Forecasting (WRF) model, are capable of simulating the full intensity of tropical cyclones (TC) with realistic structures. However, in order to accurately represent both the primary and secondary circulations in these systems, model simulations must be configured with sufficient resolution to explicitly represent convection (omitting the convective parameterization scheme). Most previous numerical studies of TC activity at seasonal and longer time scales have not utilized such explicit convection (EC) model runs. Here, we propose to employ the moving nest capability of WRF to optimally represent TC activity on a seasonal scale using a downscaling approach. The statistical results of a suite of these high-resolution TC simulations will yield a realistic representation of TC intensity on a seasonal basis, while at the same time allowing analysis of the feedback that TCs exert on the larger-scale climate system. Experiments will be driven with analyzed lateral boundary conditions for several recent Atlantic seasons, spanning a range of activity levels and TC track patterns. Results of the ensemble of WRF simulations will then be compared to analyzed TC data in order to determine the extent to which this modeling setup can reproduce recent levels of TC activity. Next, the boundary conditions (sea-surface temperature, tropopause height, and thermal/moisture profiles) from the recent seasons will be altered in a manner consistent with various future GCM/RCM scenarios, but that preserves the large-scale shear and incipient disturbance activity. This will allow (i) a direct comparison of future TC activity that could be expected for an active or inactive season in an altered climate regime, and (ii) a measure of the level of uncertainty and variability in TC activity resulting from different carbon emission scenarios.

  11. Adjustment of the Remote Tropical Climate to El Nio Conditions BENJAMIN R. LINTNER* AND JOHN C. H. CHIANG

    E-Print Network [OSTI]

    Lintner, Benjamin Richard

    convective heating anomalies that in turn cause remote tropical changes through a suite of tele- connectedAdjustment of the Remote Tropical Climate to El Ni√Īo Conditions BENJAMIN R. LINTNER* AND JOHN C. H) ABSTRACT The adjustment of the tropical climate outside the Pacific (the "remote Tropics") to the abrupt

  12. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1996-01-16T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  13. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  14. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1996-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  15. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1995-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  16. MESOSCALE SIMULATIONS OF POWDER COMPACTION

    SciTech Connect (OSTI)

    Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94551 (United States)

    2009-12-28T23:59:59.000Z

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  17. Postulated Mesoscale Quantum of Internal Friction Hysteresis

    E-Print Network [OSTI]

    Randall D. Peters

    2004-05-27T23:59:59.000Z

    Evidence is provided, from yet another experiment, for the existence of a mesoscale quantum of internal friction hysteresis, having the value of the electron rest energy divided by the fine structure constant.

  18. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1994-02-08T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  19. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M. (Macungie, PA)

    1986-01-01T23:59:59.000Z

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  20. Convective heater

    DOE Patents [OSTI]

    Thorogood, R.M.

    1983-12-27T23:59:59.000Z

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

  1. HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME

    E-Print Network [OSTI]

    Boyer, Edmond

    1 HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME P. H or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters

  2. Using Mesoscale Weather Model Output as Boundary Conditions for Atmospheric Large-Eddy Simulations and Wind-Plant Aerodynamic Simulations (Presentation)

    SciTech Connect (OSTI)

    Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.

    2013-10-01T23:59:59.000Z

    Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.

  3. SURFACE TENSION DRIVEN CONVECTION

    E-Print Network [OSTI]

    Wang, Shouhong

    SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS CONCLUDING REMARKS DYNAMIC TRANSITIONS OF SURFACE TENSION DRIVEN CONVECTION H.Dijkstra T. Sengul S. Wang #12;SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS

  4. 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

    ), Characteristics of tropical convection over the ocean near Kwajalein, Mon Weather Rev, 134, 834-853. Dessler, A. E., S. P. Palm, and J. D. Spinhirne (2006), Tropical cloud-top height distributions revealed by the Ice, Cloud, and Land Elevation Satellite...

  5. Convective-Resolving Regional Climate Simulations for the Amazon Basin: Comparison with TRMM Rainfall Data

    E-Print Network [OSTI]

    Kinney, Nichole 1987-

    2012-08-21T23:59:59.000Z

    ), Clark and Peltier (1977), and Clark (1979). It is worth mentioning that the technology at the time limited their domain size to a few tens of kilometers and their runtimes to a few hours at the spatial and temporal resolutions required to simulate a... single convective cell. In the decade after the introduction of the three-dimensional CM, CM experiments began to focus on mesoscale convective systems such as squall lines. Weisman et al. (1988) and Rotunno et al. (1988) used an evolved version...

  6. Rotational and divergent kinetic energy in the mesoscale model ALADIN

    E-Print Network [OSTI]

    Zagar, Nedjeljka

    energy, divergent energy, ALADIN, limited-area modelling 1. Introduction Horizontal divergenceRotational and divergent kinetic energy in the mesoscale model ALADIN By V. BLAZ ICA1 *, N. Z AGAR1 received 7 June 2012; in final form 7 March 2013) ABSTRACT Kinetic energy spectra from the mesoscale

  7. Building Blocks of Tropical Diabatic Heating

    SciTech Connect (OSTI)

    Hagos, Samson M.

    2010-07-01T23:59:59.000Z

    Rotated EOF analyses are used to study the composition and variability of large-scale tropical diabatic heating profiles estimated from eight field campaigns. The results show that the profiles are composed of a pair of building blocks. These are the stratiform heating with peak heating near 400hpa and a cooling peak near 700hPa and convective heating with a heating maximum near 700hPa. Variations in the contributions of these building blocks account for the evolution of the large-scale heating profile. Instantaneous top (bottom) heavy large scale heating profiles associated with excess of stratiform (convective) heating evolve towards a stationary mean profile due to exponential decay of the excess stratiform (convective) heating.

  8. Cloud shading retrieval and assimilation in a satellite-model coupled mesoscale analysis system

    SciTech Connect (OSTI)

    Lipton, A.E. (Phillips Lab., Hanscom AFB, MA (United States))

    1993-11-01T23:59:59.000Z

    A retrieval-assimilation method has been developed as a quantitative means to exploit the information in satellite imagery regarding shading of the ground by clouds, as applied to mesoscale weather analysis. Cloud radiative parameters are retrieved from satellite visible image data and used, along with parameters computed by a numerical model, to control the model's computation of downward radiative fluxes at the ground. These fluxes influence the analysis of ground surface temperatures under clouds. The method is part of a satellite-model coupled four-dimensional analysis system that merges information from visible image data in cloudy areas with infrared sounder data in clear areas, where retrievals of surface temperatures and water vapor concentrations are assimilated. The substantial impact of shading on boundary-layer development and mesoscale circulations was demonstrated in simulations, and the value of assimilating shading retrievals was demonstrated with a case study and with a simulated analysis that included the effects of several potential sources of error. The case study was performed in the northwestern Texas area, where convective cloud development was influenced by the shading effects of a persistent region of stratiform cloud cover. Analyses that included shading retrieval assimilation had consistently smaller shelter-height temperature errors than analyses without shading retrievals. When clear-area surface temperature retrievals from sounder data were analyzed along with cloudy-area shading retrievals, the contrast in heating between the shaded and clear parts of the domain led to large variations in analyzed boundary-layer depths and had a modest impact on analyzed wind flow. The analyzed locations of upward vertical motion corresponded roughly to areas of convective cloud development observed in satellite imagery. 29 refs., 17 figs., 2 tabs.

  9. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    SciTech Connect (OSTI)

    Jensen, Michael

    2014-04-10T23:59:59.000Z

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  10. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

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

    Jensen, Michael

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  11. Evolution of vertical drafts and cloud-to-ground lightning within the convective region of a mesoscale convective complex

    E-Print Network [OSTI]

    Saul, Scott Henry

    1995-01-01T23:59:59.000Z

    for the degree of MASTER OF SCIENCE Approved as to style and content by: Michael I. Big taff (Chair of Committee) Richard E. Orville (Member) Ja . Li ng ber) Edward . Z' se (Head of Department) August 1995 Major Subject: Meteorology ABSTRACT.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . 50 26 Histograms of the vertical velocity distribution at 1. 9 km height for the west lobe from 0905-1042 UTC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 27 As in Fig. 26 except for (a) east lobe from 0914...

  12. Mesoscale Quantization and Self-Organized Stability

    E-Print Network [OSTI]

    Randall D. Peters

    2005-06-16T23:59:59.000Z

    In the world of technology, one of the most important forms of friction is that of rolling friction. Yet it is one of the least studied of all the known forms of energy dissipation. In the present experiments we investigate the oscillatory free-decay of a rigid cube, whose side-length is less than the diameter of the rigid cylinder on which it rests. The resulting free-decay is one of harmonic motion with damping. The non-dissipative character of the oscillation yields to a linear differential equation; however, the damping is found to involve more than a deterministic nonlinearity. Dominated by rolling friction, the damping is sensitive to the material properties of the contact surfaces. For `clean' surfaces of glass on glass, the decay shows features of mesoscale quantization and self-organized stability.

  13. Identifying the top of the tropical tropopause layer from vertical mass flux analysis and CALIPSO lidar cloud observations

    E-Print Network [OSTI]

    Hochberg, Michael

    deep convection from the tropical rainfall measuring mission precipitation radar, Alcala and Dessler defined as the level of zero net radiative heating, which occurs near 14.5­15 km [e.g., Folkins et al convection occurring below this level will sink back to the surface, and air detraining above this level

  14. Impact of Secondary Eyewall Heating on Tropical Cyclone Intensity Change* XIAQIONG ZHOU, BIN WANG, XUYANG GE, AND TIM LI

    E-Print Network [OSTI]

    Wang, Bin

    Impact of Secondary Eyewall Heating on Tropical Cyclone Intensity Change* XIAQIONG ZHOU, BIN WANG is to explore the factors that might influence the intensity change of tropical cyclones (TCs) associated. Introduction Concentric eyewalls usually refer to two or more quasi-circular eyewalls separated by a convective

  15. Evolution of cloud-to-ground lightning characteristics within the convective region of a midlatitude squall line

    E-Print Network [OSTI]

    Billingsley, David Brian

    2012-06-07T23:59:59.000Z

    region, descending through an area of mesoscale descent, and reaching the rear of the convective line near the surface. Though not explicitly shown in Fig. 7, a transition zone of weak echo between the convective and stratiform regions has also been...-levels define the grid points of the template. The scheme focuses on inclusion of the developing mid-level cells in the forward part of the squall line and exclusion of the transition zone at lower levels in the rearward portion of the line. The templates...

  16. Observations, dynamics and predictability of the mesoscale convective vortex event of 10-13 June 2003

    E-Print Network [OSTI]

    Hawblitzel, Daniel Patrick

    2006-08-16T23:59:59.000Z

    dynamics and predictability given the anomalously strong and long-lived nature of the circulation and the dense data set. The first part of this study explores the dynamics of this MCV through an in-depth analysis of data from the profiler network and BAMEX...

  17. Convective variability associated with a mesoscale vortex in a midlatitude squall line system

    E-Print Network [OSTI]

    Hristova-Veleva, Svetla M.

    1994-01-01T23:59:59.000Z

    . . . . . . . . . . CASE DESCRIPTION. . STORM MORPHOLOGY Low Levels (surface to 1. 9 km) Mid-to-Low Levels (2. 4 to 3. 9 km). . . . . . . . Mid-to-Upper Levels (4. 4 to 8. 9 km). . . . . . Upper Levels (9. 4 km and above). . . . . . . . . . Vertical Cross... Streamline/isotachanalysisofstorm-relativewinds at1150UTCon 28 May 1985. 1152 UTC dual Doppler analysis of kinematic and reflectivity field at 1. 4 km Mean Sea Level (MSL). . 47 , . 49 20b 1152 UTC dual Doppler analysis of the storm-relative horizontal...

  18. Experiment to Characterize Tropical Cloud Systems

    SciTech Connect (OSTI)

    May, Peter T.; Mather, Jim H.; Jakob, Christian

    2005-08-02T23:59:59.000Z

    A major experiment to study tropical convective cloud systems and their impacts will take place around Darwin, Northern Australia in early 2006. The Tropical Warm Pool International Cloud Experiment (TWP-ICE) is a collaboration including the DOE ARM (Atmospheric Radiation Measurement) and ARM-UAV programs, NASA centers, the Australian Bureau of Meteorology, CSIRO, and universities in the USA, Australia, Japan, the UK, and Canada. TWP-ICE will be preceded in November/December 2004 by a collaborating European aircraft campaign involving the EU SCOUT-O3 and UK NERC ACTIVE projects. Detailed atmospheric measurements will be made in the Darwin area through the whole Austral summer, giving unprecedented coverage through the pre-monsoon and monsoon periods.

  19. Tropical Cyclone Intensification from Asymmetric Convection: Energetics and Efficiency

    E-Print Network [OSTI]

    Nolan, David S.

    and some new methods of analysis. The model equations have been changed to be more consistent and available potential energies are presented for both asymmetric and symmetric motions, and these are used to quantify the flow of energy from localized, asymmetric heat sources to kinetic energy of the wind field

  20. Vertical velocity in oceanic convection off tropical Australia

    E-Print Network [OSTI]

    Lucas, Christopher

    2012-06-07T23:59:59.000Z

    . . . . . . . v Vl Vl I I 1 3 6 10 Description of the Data Data Processing . . Event Criteria 10 15 21 III RESULTS . . . 26 Cores. Environment 26 34 IV COMPARISON WITH OTHER STUDIES . . . . . 40 Cores... Variations with altitude of median and strongest 10'/o-level statistics of (a) average vertical velocity, (b) maximum vertical velocity, (c) mass flux per unit length normal to the flight track and (d) diameter 32 Figure Page Reconstructed temperature...

  1. Limiting Factors for Convective Cloud Top Height in the Tropics

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011Liisa O'Neill About Us Liisa O'NeillLimiting

  2. Patterns of Convection in the Tropical Western Pacific

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006 TheSteven AshbyDepartment ofGE's E.Gilman About UsScience

  3. Properties of tropical convection observed by ARM millimeter-radars

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - SeptemberMicroneedles for4-16HamadaBaO/Al2O3 lean NOx trapProofreadingProperties

  4. Self-Assembly of Mesoscale Isomers: The Role of Pathways and Degrees of Freedom

    E-Print Network [OSTI]

    Menon, Govind

    Self-Assembly of Mesoscale Isomers: The Role of Pathways and Degrees of Freedom Shivendra Pandey1 geometric path sampling and a mesoscale experimental model to investigate the self-assembly of a model. Citation: Pandey S, Johnson D, Kaplan R, Klobusicky J, Menon G, et al. (2014) Self-Assembly of Mesoscale

  5. Review of structure representation and reconstruction on mesoscale and microscale

    SciTech Connect (OSTI)

    Li, Dongsheng

    2014-05-01T23:59:59.000Z

    Structure representation and reconstruction on mesoscale and microscale is critical in material design, advanced manufacturing and multiscale modeling. Microstructure reconstruction has been applied in different areas of materials science and technology, structural materials, energy materials, geology, hydrology, etc. This review summarizes the microstructure descriptors and formulations used to represent and algorithms to reconstruct structures at microscale and mesoscale. In the stochastic methods using correlation function, different optimization approaches have been adapted for objective function minimization. A variety of reconstruction approaches are compared in efficiency and accuracy.

  6. 5, 1102911054, 2005 Convective gravity

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 5, 11029­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Discussions Wind-profiler observations of gravity waves produced by convection at mid-latitudes Y. G. Choi1­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Abstract Introduction

  7. 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

  8. The Tropical Warm Pool International Cloud Experiment

    SciTech Connect (OSTI)

    May, Peter T.; Mather, James H.; Vaughan, Geraint; Jakob, Christian; McFarquhar, Greg; Bower, Keith; Mace, Gerald G.

    2008-05-01T23:59:59.000Z

    One of the most complete data sets describing tropical convection ever collected will result from the upcoming Tropical Warm Pool International Cloud Experiment (TWP-ICE) in the area around Darwin, Northern Australia in January and February 2006. The aims of the experiment, which will be operated in conjunction with the DOE Atmospheric Radiation Measurement (ARM) site in Darwin, will be to examine convective cloud systems from their initial stages through to the decay of the cirrus generated and to measure their impact on the environment. The experiment will include an unprecedented network of ground-based observations (soundings, active and passive remote sensors) combined with low, mid and high altitude aircraft for in-situ and remote sensing measurements. A crucial outcome of the experiment will be a data set suitable to provide the forcing and evaluation data required by cloud resolving and single column models as well as global climate models (GCMs) with the aim to contribute to parameterization development. This data set will provide the necessary link between the observed cloud properties and the models that are attempting to simulate them. The experiment is a large multi-agency experiment including substantial contributions from the United States DOE ARM program, ARM-UAV program, NASA, the Australian Bureau of Meteorology, CSIRO, EU programs and many universities.

  9. Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez

    E-Print Network [OSTI]

    Gilbes, Fernando

    Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez Department of Marine Sciences, P-term goal is to improve predictivity of physical, biogeochemical and optical properties of Eastern Caribbean, biological and optical variables across frontal and eddy boundaries in the Eastern Caribbean Sea · To develop

  10. Wind resource assessment with a mesoscale non-hydrostatic model

    E-Print Network [OSTI]

    Boyer, Edmond

    Wind resource assessment with a mesoscale non- hydrostatic model Vincent Guénard, Center for Energy is developed for assessing the wind resource and its uncertainty. The work focuses on an existing wind farm mast measurements. The wind speed and turbulence fields are discussed. It is shown that the k

  11. Molecule-Mimetic Chemistry and Mesoscale Self-Assembly

    E-Print Network [OSTI]

    Prentiss, Mara

    Molecule-Mimetic Chemistry and Mesoscale Self-Assembly NED B. BOWDEN, MARCUS WECK, INSUNG S. CHOI systems. We suggest that it will be possible to develop complex structures composed of "objects" that self-assemble, shape recognition, and size exclusion can be used to guide the self-assembly of these objects

  12. LANSCE School on Neutron Scattering: Materials at the Mesoscale

    E-Print Network [OSTI]

    1 11th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos. Please name the applicant for admission to the 11th LANSCE School on Neutron Scattering: Last, First LANSCE School on Neutron Scattering including: drive and motivation, ability to work with others

  13. MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN

    E-Print Network [OSTI]

    Pielke, Roger A.

    MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN (ReviewArticle) Y. MAHRER.1. OBSERVATIONALAPPROACHES Evaluations of wind energy based on wind observations (usually surface winds) at well, the resolution of the wind energy pattern throughout an extended area by this methodology requires a large number

  14. WIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO-AND MESOSCALE MODELLING

    E-Print Network [OSTI]

    sets for evaluating the potential wind power output from large electricity-producing wind turbine and accurate wind atlas data sets for evaluating the potential wind power output from large electricityWIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO- AND MESOSCALE MODELLING Niels G. Mortensen1 , Jens

  15. Can the vertical motions in the eyewall of tropical cyclones support persistent UAV flight?

    E-Print Network [OSTI]

    Poh, Chung-Kiak

    2014-01-01T23:59:59.000Z

    Powered flights in the form of manned or unmanned aerial vehicles (UAVs) have been flying into tropical cyclones to obtain vital atmospheric measurements with flight duration typically lasting between 12 and 36 hours. Convective vertical motion properties of tropical cyclones have previously been studied. This work investigates the possibility to achieve persistent flight by harnessing the generally pervasive updrafts in the eyewall of tropical cyclones. A sailplane UAV capable of vertical take-off and landing (VTOL) is proposed and its flight characteristics simulated. Results suggest that the concept of persistent flight within the eyewall is promising and may be extendable to the rainband regions.

  16. Tropical Underdevelopment Jeffrey D. Sachs

    E-Print Network [OSTI]

    of mobilizing energy resources in tropical economies is emphasized as another significant contributor measure of economic development. Tropical and landlocked regions, by contrast ≠ such as Bolivia, Chad

  17. Development of Ensemble Neural Network Convection Parameterizations for Climate Models

    SciTech Connect (OSTI)

    Fox-Rabinovitz, M. S.; Krasnopolsky, V. M.

    2012-05-02T23:59:59.000Z

    The novel neural network (NN) approach has been formulated and used for development of a NN ensemble stochastic convection parametrization for climate models. This fast parametrization is built based on data from Cloud Resolving Model (CRM) simulations initialized with and forced by TOGA-COARE data. The SAM (System for Atmospheric Modeling), developed by D. Randall, M. Khairoutdinov, and their collaborators, has been used for CRM simulations. The observational data are also used for validation of model simulations. The SAM-simulated data have been averaged and projected onto the GCM space of atmospheric states to implicitly define a stochastic convection parametrization. This parametrization is emulated using an ensemble of NNs. An ensemble of NNs with different NN parameters has been trained and tested. The inherent uncertainty of the stochastic convection parametrization derived in such a way is estimated. Due to these inherent uncertainties, NN ensemble is used to constitute a stochastic NN convection parametrization. The developed NN convection parametrization have been validated in a diagnostic CAM (CAM-NN) run vs. the control CAM run. Actually, CAM inputs have been used, at every time step of the control/original CAM integration, for parallel calculations of the NN convection parametrization (CAM-NN) to produce its outputs as a diagnostic byproduct. Total precipitation (P) and cloudiness (CLD) time series, diurnal cycles, and P and CLD distributions for the large Tropical Pacific Ocean for the parallel CAM-NN and CAM runs show similarity and consistency with the NCEP reanalysis. The P and CLD distributions for the tropical area for the parallel runs have been analyzed first for the TOGA-COARE boreal winter season (November 1992 through February 1993) and then for the winter seasons of the follow-up parallel decadal simulations. The obtained results are encouraging and practically meaningful. They show the validity of the NN approach. This constitutes an important practical conclusion of the study: the obtained results on NN ensembles as a stochastic physics parametrization show a realistic possibility of development of NN convection parametrization for climate (and NWP) models based on learning cloud physics from CRM/SAM simulated data.

  18. 1234 VOLUME 42J O U R N A L O F A P P L I E D M E T E O R O L O G Y Radiative and Microphysical Characteristics of Deep Convective Systems in the

    E-Print Network [OSTI]

    precipitation radar and Geostationary Meteorological Satellite infrared radiometer measurements are used%. In cases in which the convective available potential energy (CAPE) is large, deep convective clouds roles in producing the high albedos of tropical anvil clouds. A comparison of the radiative heating

  19. The Tropical Atmospheric El Nio Signal in Satellite Precipitation Data and a Global Climate Model

    E-Print Network [OSTI]

    ) ABSTRACT Aspects of the tropical atmospheric response to El Ni√Īo related to the global energy and water and the Advanced Micro- wave Scanning Radiometer-E and simulations from the Goddard Institute for Space Studies are highly correlated, but anomalies in stratiform¬≠convective rainfall partitioning in the two datasets

  20. Overshooting Convection from High-resolution NEXRAD Observations

    E-Print Network [OSTI]

    Solomon, David

    2014-01-09T23:59:59.000Z

    employs the difference between 6-7 Ķm water vapor absorption and ?11 Ķm infrared window channel brightness temper- ature for overshooting convection detection (e.g., Fritz and Laszlo, 1993; Ackerman, 2 1996; Schmetz et al., 1997; Setvak et al., 2007... and in Radiative Forcing, pp. 129Ė234, Cambridge University Press, Cambridge, UK. Fritz, S., and I. Laszlo (1993), Detection of water vapor in the stratosphere over very high clouds in the tropics, J. Geophys. Res., 98 (D12), 22,959Ė22,967. 32 Fromm, M. D., and R...

  1. Mesoscale Modeling of LX-17 Under Isentropic Compression

    SciTech Connect (OSTI)

    Springer, H K; Willey, T M; Friedman, G; Fried, L E; Vandersall, K S; Baer, M R

    2010-03-06T23:59:59.000Z

    Mesoscale simulations of LX-17 incorporating different equilibrium mixture models were used to investigate the unreacted equation-of-state (UEOS) of TATB. Candidate TATB UEOS were calculated using the equilibrium mixture models and benchmarked with mesoscale simulations of isentropic compression experiments (ICE). X-ray computed tomography (XRCT) data provided the basis for initializing the simulations with realistic microstructural details. Three equilibrium mixture models were used in this study. The single constituent with conservation equations (SCCE) model was based on a mass-fraction weighted specific volume and the conservation of mass, momentum, and energy. The single constituent equation-of-state (SCEOS) model was based on a mass-fraction weighted specific volume and the equation-of-state of the constituents. The kinetic energy averaging (KEA) model was based on a mass-fraction weighted particle velocity mixture rule and the conservation equations. The SCEOS model yielded the stiffest TATB EOS (0.121{micro} + 0.4958{micro}{sup 2} + 2.0473{micro}{sup 3}) and, when incorporated in mesoscale simulations of the ICE, demonstrated the best agreement with VISAR velocity data for both specimen thicknesses. The SCCE model yielded a relatively more compliant EOS (0.1999{micro}-0.6967{micro}{sup 2} + 4.9546{micro}{sup 3}) and the KEA model yielded the most compliant EOS (0.1999{micro}-0.6967{micro}{sup 2}+4.9546{micro}{sup 3}) of all the equilibrium mixture models. Mesoscale simulations with the lower density TATB adiabatic EOS data demonstrated the least agreement with VISAR velocity data.

  2. E-Print Network 3.0 - approximate mesoscale information Sample...

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

    of Technology Collection: Engineering 5 Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda Atlantic Summary: coverage. GLOVER ET...

  3. Different convection models in ATLAS

    E-Print Network [OSTI]

    Barry Smalley

    2005-09-19T23:59:59.000Z

    Convection is an important phenomenon in the atmospheres of A-type and cooler stars. A description of convection in ATLAS models is presented, together with details of how it is specified in model calculations. The effects of changing the treatment of convection on model structures and how this affects observable quantities are discussed. The role of microturbulence is examined, and its link to velocity fields within the atmosphere. Far from being free parameters, mixing-length and microturbulence should be constrained in model calculations.

  4. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.; Yamaguchi, K.

    1983-01-01T23:59:59.000Z

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  5. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Natural convection can provide adequate heat distribution in many situtations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others or to reduce the number of heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures is predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Natural convective loops that can occur in buildings are described and a few design guidelines are presented.

  6. Mesoscale Self-Assembly of Hexagonal Plates Using Lateral Capillary Forces: Synthesis Using the "Capillary Bond"

    E-Print Network [OSTI]

    Prentiss, Mara

    Mesoscale Self-Assembly of Hexagonal Plates Using Lateral Capillary Forces: Synthesis Using examines self-assembly in a quasi-two-dimensional, mesoscale system. The system studied here involves and hydrophilic faces on the hexagonal plates led to three outcomes: (i) the extension of the strategies of self-assembly

  7. Sensitivity of mesoscale gravity waves to the baroclinicity of jet-front systems

    E-Print Network [OSTI]

    Wang, Shuguang

    2006-04-12T23:59:59.000Z

    To investigate the generation of mesoscale gravity waves from upper-tropospheric jet-front systems, five different life cycles of baroclinic waves are simulated with a high-resolution mesoscale model (MM5 with 10-km grid spacing). The baroclinicity...

  8. Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1

    E-Print Network [OSTI]

    Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1 ABSTRACT The generation of strong mesoscale variability through instability of the large-scale circulation in the interior of oceanic gyres is addressed. While previous studies have shown that eddies generated from weakly sheared

  9. Respective roles of shallow convection and stratiform rainfall on the simulation of Madden-Julian Oscillation.

    SciTech Connect (OSTI)

    Fu, Joshua Xiouhua [IPRC/SOEST/UH; Wang, Bin [IPRC& DM/SOEST/UH; Yeh, Hsi-Chyi

    2010-03-15T23:59:59.000Z

    Respective Roles of Shallow Convection and Stratiform Rainfall on the Simulation of Madden Julian Oscillation Joshua Xiouhua Fu IPRC, SOEST, University of Hawaii The IPRC/UH Hybrid-coupled GCM (HcGCM), which combined ECHAM-4 AGCM with UH intermediate ocean model, produces robust Tropical Intra-Seasonal Oscillations including the boreal-winter MJO and boreal-summer Monsoon Intra-Seasonal Oscillation. In this study, two sets of sensitivity experiments (i.e., short-term retrospective forecast of one MJO event observed during TOGA COARE and long-term free integrations) have been carried out to understand the respective roles of shallow-convection and stratiform rainfall on the simulations and predictions of the MJO. Major findings are summarized as following: Shallow-convection ahead of MJO deep convection moistens the lower-troposphere and preconditions the movement of the MJO. Present study shows that this process is very important to the eastward propagating speed of the MJO. A significant fraction of stratiform rainfall (~30%; stratiform part vs. total rainfall) is needed for ECHAM-4 to have a robust MJO. The above findings suggest that in addition to deep convection, shallow convection and stratiform rainfall needs to be well represented in conventional GCMs to ensure a robust model MJO.

  10. Biodiversity Conservation in Tropical Agroecosystems

    E-Print Network [OSTI]

    Biodiversity Conservation in Tropical Agroecosystems A New Conservation Paradigm Ivette Perfectoa areas of the world. Although most ecologists con- cerned with biodiversity conservation would agree. This conclusion has major consequences for biodiversity con- servation in fragmented tropical forests

  11. Customizing mesoscale self-assembly with 3D printing

    E-Print Network [OSTI]

    M. Poty; G. Lumay; N. Vandewalle

    2013-10-17T23:59:59.000Z

    Self-assembly due to capillary forces is a common method for generating 2D mesoscale structures from identical floating particles at the liquid-air interface. Designing building blocks to obtain a desired mesoscopic structure is a scientific challenge. We show herein that it is possible to shape the particles with a low cost 3D printer, for composing specific mesoscopic structures. Our method is based on the creation of capillary multipoles inducing either attractive or repulsive forces. Since capillary interactions can be downscaled, our method opens new ways to low cost microfabrication.

  12. Poster Sessions J. Dudhia Mesoscale and Microscale Meteorology Division

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006PhotovoltaicSeptember 22, 2014SocietyJ. Dudhia Mesoscale and

  13. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Natural convection can provide adequate heat distribution in many situations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others. Natural convection can also be used to reduce the number of auxiliary heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures are predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Experimental results are summarized based on the monitoring of 15 passive solar buildings which employ a wide variety of geometrical configurations including natural convective loops.

  14. Development and evaluation of a convection scheme for use in climate models

    SciTech Connect (OSTI)

    Emanuel, K.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate; Zivkovic-Rothman, M. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)] [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

    1999-06-01T23:59:59.000Z

    Cumulus convection is a key process in controlling the water vapor content of the atmosphere, which is in turn the largest feedback mechanism for climate change in global climate models. Yet scant attention has been paid to designing convective representations that attempt to handle water vapor with fidelity, and even less to evaluating their performance. Here the authors attempt to address this deficiency by designing a representation of cumulus convection with close attention paid to convective water fluxes and by subjecting the scheme to rigorous tests using sounding array data. The authors maintain that such tests, in which a single-column model is forced by large-scale processes measured by or inferred from the sounding data, must be carried out over a period at least as long as the radiative-subsidence timescale--about 30 days--governing the water vapor adjustment time. The authors also argue that the observed forcing must be preconditioned to guarantee integral enthalpy conservation, else errors in the single-column prediction may be falsely attributed to convective schemes. Optimization of the new scheme`s parameters is performed using one month of data from the intensive flux array operating during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, with the aid of the adjoint of the linear tangent of the single-column model. Residual root-mean-square errors, after optimization, are about 15% in relative humidity and .8 K in temperature. It is difficult to reject the hypothesis that the residual errors are due to noise in the forcing. Evaluation of the convective scheme is performed using Global Atmospheric Research Program Atlantic Tropical Experiment data. The performance of the scheme is compared to that of a few other schemes used in current climate models. It is also shown that a vertical resolution better than 50 mb in pressure is necessary for accurate prediction of atmospheric water vapor.

  15. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, J.C.; Hardee, H.C.; Striker, R.P.

    1984-01-09T23:59:59.000Z

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

  16. Tropical Limit in Statistical Physics

    E-Print Network [OSTI]

    M. Angelelli; B. Konopelchenko

    2015-02-04T23:59:59.000Z

    Tropical limit for macroscopic systems in equilibrium defined as the formal limit of Boltzmann constant k going to 0 is discussed. It is shown that such tropical limit is well-adapted to analyse properties of systems with highly degenerated energy levels, particularly of frustrated systems like spin ice and spin glasses. Tropical free energy is a piecewise linear function of temperature, tropical entropy is a piecewise constant function and the system has energy for which tropical Gibbs' probability has maximum. Properties of systems in the points of jump of entropy are studied. Systems with finite and infinitely many energy levels and phenomena of limiting temperatures are discussed.

  17. 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.

  18. 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 Ė 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 Darwinís 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.

  19. Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

    2012-04-11T23:59:59.000Z

    A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling methods used in this study.

  20. ARM - Midlatitude Continental Convective Clouds

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

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  1. Data assimilation for stratified convection

    E-Print Network [OSTI]

    Svedin, Andreas; Brandenburg, Axel

    2013-01-01T23:59:59.000Z

    We show how the 3DVAR data assimilation methodology can be used in the astrophysical context of a two-dimensional convection flow. We study the way this variational approach finds best estimates of the current state of the flow from a weighted average of model states and observations. We use numerical simulations to generate synthetic observations of a vertical two-dimensional slice of the outer part of the solar convection zone for varying noise levels and implement 3DVAR when the covariance matrices are scalar. Our simulation results demonstrate the capability of 3DVAR to produce error estimates of system states between up to tree orders of magnitude below the original noise level present in the observations. This work exemplifies the importance of applying data assimilation techniques in simulations of the stratified convection.

  2. A Statistical Analysis of Characteristics of Mesoscale Convective System Mountain Initiation Location Clusters in the Arkansas-Red River Basin

    E-Print Network [OSTI]

    Callen, Elisabeth F.

    2012-12-31T23:59:59.000Z

    to anticipate flooding events that can occur with these systems. The multi-sensor precipitation data, a combination of satellite, radar, and rain gage data, was used in Tucker and Li (2009). The MCSs initiating west of 104? W in the warm season (April...

  3. Feedbacks in a simple prognostic tropical climate model

    SciTech Connect (OSTI)

    Sherwood, S.C. (Scripps Institution of Oceanography, La Jolla, CA (United States))

    1999-07-01T23:59:59.000Z

    A simple four-cell model of the tropical atmosphere in equilibrium with its boundaries is introduced, which can support a variable diabatic circulation and prognostic temperature and humidity profiles. The model is used to predict atmospheric perturbations away from the observed base state. Prognostic variables include radiation, surface fluxes, and dynamic transports, with temperature and water vapor levels determined by conservation constraints. The model includes a specially developed water vapor scheme that performs favorably compared with observations. The model is used to simulate the local and nonlocal sensitivity of the tropical maritime atmosphere to changes in surface temperature and other boundary conditions at very large horizontal scales. The main findings are as follows: (i) The sensitivity of boundary layer convergence to sea surface temperature (SST) variations depends on the behavior of convective heating over cooler regions and may be overestimated by heuristic models that ignore or oversimplify thermodynamic and radiative constraints; (ii) The maintenance of humidity equilibrium over weakly convective areas is modulated by local radiative feedback; (iii) Evaporation feedbacks on SST may be overestimated by heuristic arguments that do not carefully treat atmospheric water transport. An explanation for the constant-relative humidity behavior of general circulation models under climate changes is also offered based on the results.

  4. Meso-Scale Model for Simulations of Concrete Subjected to Cryogenic Temperatures

    E-Print Network [OSTI]

    Masad, Noor Ahmad

    2013-07-17T23:59:59.000Z

    software ABAQUS. In this model, concrete is considered as a 3- phase composite material in a meso-scale structure: mortar matrix, aggregate, and interfacial transmission zone (ITZ). The Concrete Damage Plasticity model in ABAQUS is used to represent...

  5. Mesoscale Origin of the Enhanced Cycling-Stability of the Si...

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

    Mesoscale Origin of the Enhanced Cycling-Stability of the Si-Conductive Polymer Anode for Li-ion Batteries. Abstract: Electrode used in lithium-ion battery is invariably a...

  6. Design of a high-speed, meso-scale nanopositioners driven by electromagnetic actuators

    E-Print Network [OSTI]

    Golda, Dariusz, 1979-

    2008-01-01T23:59:59.000Z

    The purpose of this thesis is to generate the design and fabrication knowledge that is required to engineer high-speed, six-axis, meso-scale nanopositioners that are driven by electromagnetic actuators. When compared to ...

  7. Processing of cloud condensation nuclei by collision-coalescence in a mesoscale model

    E-Print Network [OSTI]

    Mechem, David B.; Robinson, Paul C.; Kogan, Yefim L.

    2006-09-26T23:59:59.000Z

    The Naval Research Laboratory's Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) is employed to explore the relative importance of source, sink, and transport processes in producing an accurate forecast of the ...

  8. NATURAL CONVECTION IN ROOM GEOMETRIES

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, Fred; Kammerud, R.; Ruberg, K.

    1980-06-01T23:59:59.000Z

    Computer programs have been developed to numerically simulate natural convection in room geometries in two and three dimensions. The programs have been validated using published data from the literature, results from a full-scale experiment performed at Massachusetts Institute of Technology, and results from a small-scale experiment reported here. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single thermal zone in a direct-gain passive solar building. The results indicate that the building heating loads calculated by standard building energy analysis methods may be in error by as much as 50% as a result of their use of common assumptions regarding the convection processes which occur in an enclosure. It is also found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface.

  9. 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.

  10. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS

    SciTech Connect (OSTI)

    Anter El-Azab

    2013-04-08T23:59:59.000Z

    The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation motion and dislocation interaction in the crystal. Part of this effort also targeted the theoretical basis for establishing the connection between discrete and continuum representation of dislocations and the analysis of discrete dislocation simulation results within the continuum framework. This part of the research enables the enrichment of the kinetic description with information representing the discrete dislocation systems behavior. The third task focused on the development of physics-inspired numerical methods of solution of the coupled dislocation kinetics and crystal mechanics framework. To a large extent, this task has also been successfully started. We have developed a custom finite-element approach with mesh points being a subset of the underlying crystal structure. When used to predict the evolution of the dislocation system, the planar motion of dislocations is naturally captured for all slip systems, thus minimizing numerical errors and providing simple ways to investigate cross slip and dislocation reactions. Preliminary results in this direction show that we are closer than ever in building a predictive framework for dislocation dynamics and mesoscale plasticity based on the first principles of dislocation dynamics. The rest of the report gives and overview of the research performed under this project and highlights the key results and open questions left for future investigations.

  11. Ten Years of Measurements of Tropical Upper-Tropospheric Water Vapor by MOZAIC. Part I: Climatology, Variability, Transport, and Relation to

    E-Print Network [OSTI]

    Lombardi, John R.

    the International Satellite Cloud Climatology Project (ISCCP). 1. Introduction Water vapor is the key atmosphericTen Years of Measurements of Tropical Upper-Tropospheric Water Vapor by MOZAIC. Part I: Climatology, Variability, Transport, and Relation to Deep Convection ZHENGZHAO LUO, DIETER KLEY,* AND RICHARD H. JOHNSON

  12. Manufacturing Ultra-Precision Meso-scale Products by Coining

    SciTech Connect (OSTI)

    Seugling, R M; Davis, P J; Rickens, K; Osmer, J; Brinksmeier, E

    2010-02-18T23:59:59.000Z

    A method for replicating ultra-precision, meso-scale features onto a near-net-shape metallic blank has been demonstrated. The 'coining' technology can be used to imprint a wide range of features and/or profiles into two opposing surfaces. The instrumented system provides the ability to measure and control the product thickness and total thickness variation (TTV). The coining mechanism relies on kinematic principles to accurately and efficiently produce ultra-precision work pieces without the production of by products such as machining chips, or grinding swarf while preserving surface finish, material structure and overall form. Coining has been developed as a niche process for manufacturing difficult to machine, millimeter size components made from materials that may present hazardous conditions. In the case described in this paper a refractory metal part, tantalum (Ta) was produced with 4 {micro}m peak to valley 50 {micro}m special wavelength sine wave coined into the surface of 50 {micro}m blank. This technique shows promise for use on ductile materials that cannot be precision machined with conventional single crystal diamond tooling and/or has strict requirements on subsurface damage, surface impurities and grain structure. As a production process, it can be used to reduce manufacturing costs where large numbers of ultra-precision, repetitive designs are required and produce parts out of hazardous materials without generating added waste.

  13. MICRO-SEISMOMETERS VIA ADVANCED MESO-SCALE FABRICATION

    SciTech Connect (OSTI)

    Garcia, Caesar A; Onaran, Guclu; Avenson, Brad; Hall, Neal

    2014-11-07T23:59:59.000Z

    The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) seek revolutionary sensing innovations for the monitoring of nuclear detonations. Performance specifications are to be consistent with those obtainable by only an elite few products available today, but with orders of magnitude reduction in size, weight, power, and cost. The proposed commercial innovation calls upon several technologies including the combination of meso-scale fabrication and assembly, photonics-based displacement / motion detection methods, and the use of digital control electronics . Early Phase II development has demonstrated verified and repeatable sub 2ng noise floor from 3Hz to 100Hz, compact integration of 3-axis prototypes, and robust deployment exercises. Ongoing developments are focusing on low frequency challenges, low power consumption, ultra-miniature size, and low cross axis sensitivity. We are also addressing the rigorous set of specifications required for repeatable and reliable long-term explosion monitoring, including thermal stability, reduced recovery time from mass re-centering and large mechanical shocks, sensitivity stability, and transportability. Successful implementation will result in small, hand-held demonstration units with the ability to address national security needs of the DOE/NNSA. Additional applications envisioned include military/defense, scientific instrumentation, oil and gas exploration, inertial navigation, and civil infrastructure monitoring.

  14. Copyrighted Material What Is Tropical Ecology?

    E-Print Network [OSTI]

    Landweber, Laura

    Copyrighted Material What Is Tropical Ecology? Asking the question, What is tropical ecology? may seem akin to asking questions such as, Who is buried in Grant's tomb? Tropical ecology is the study of the ecology of tropical regions. But so what? Consider these questions: First, what is ecology? What are its

  15. Mesoscale Tank Experiments for Investigating Carbon Tetrachloride Biodegradation

    SciTech Connect (OSTI)

    Brady D. Lee; Robert J. Lenhard

    2005-06-01T23:59:59.000Z

    Mesoscale tank experiments were performed to simulate bioremediation of saturated zone carbon tetrachloride (CCl4) originating from a vadose zone carbon tetrachloride source. The mesoscale tank is 2-m wide by 2-m high by 3-m long and was constructed of stainless steel, yielding a total volume of 12 m3. Simulated geology within the tank consisted of two unconsolidated sand layers separated by a clay layer containing variable-sized stainless steel tubes that represented fractures within a consolidated porous medium. The thickness of the upper sand layer was approximately 55 cm, the thickness of the virtual fracture layer was 25 cm, and the thickness of the lower sand layer was approximately 98 cm. The water table was located at an elevation of approximately 54 cm from the bottom of the tank. CCl4 was added to the sealed tank by pouring 500 ml of neat CCl4 into a beaker buried approximately 10 cm below the upper sand surface through a stainless steel tube. The CCl4 was then allowed to partition through the reactor over time, eventually coming to equilibrium. Once CCl4 equilibrium had occurred in the saturated zone (~500 ppb); the reactor was bioaugmented with a CCl4 degrading culture enriched from the Subsurface Disposal Area at the INEEL. The culture was grown to a cell density of ~ 1.0 x 108 cells/ml and injected into the simulated aquifer through a center sampling port. Following injection of the culture, an initial aliquot of lactate (1,000 g/L), nitrogen, and phosphorus were added to the reactor. Lactate was injected every 3 Ė 5 days for one month. After 1 month of operation, a continuous supply of lactate (1,000 g/L) was pumped into the reactor at an average rate of 50 mL/min. CCl4 concentrations in the unsaturated zone were measured using hollow fiber membrane samplers, while liquid samples were analyzed to monitor levels in the simulated aquifer zone. Samples were also taken for analysis of volatile organic acids and cell density. As would be expected, increases in cell density over the length of the cell correlated with the flow of the water through the cell. One week following injection microbes and lactate, cell numbers were in the range of 5.0 x 106 cells/mL, by the end of the experiment cell numbers had increased to approximately 1.94 x 107 cells/mL. Five days after lactate injection was initiated, chloroform appeared in liquid samples taken for chlorinated VOC analysis. CCl4 concentrations in the liquid phase dropped to approximately 180 ppb. At the conclusion of the batch lactate injection phase of the bioaugmentation, CCl4 levels averaged 40 ppb and chloroform levels averaged 44 ppb. Interestingly, once continuous lactate addition was initiated, CCl4 concentrations in the saturated zone increased with spikes as high as 3,000 ppb. Chloroform concentrations also increased following continuous addition of lactate. Since the CCl4 source in the breaker had been depleted, vadose zone concentrations of CCl4 dropped steadily during addition of lactate to the saturated zone. CCl4 levels of ~ 800 ppmv were noted at the beginning of the experiment, levels decreased to below 200 ppmv by the end of the bioaugmentation phase. No chloroform was noted in the vadose zone during testing.

  16. Elastic Convection in Vibrated Viscoplastic Fluids

    E-Print Network [OSTI]

    Hayato Shiba; Jori Ruppert-Felsot; Yoshiki Takahashi; Yoshihiro Murayama; Qi Ouyang; Masaki Sano

    2006-08-07T23:59:59.000Z

    We observe a new type of behavior in a shear thinning yield stress fluid: freestanding convection rolls driven by vertical oscillation. The convection occurs without the constraint of container boundaries yet the diameter of the rolls is spontaneously selected for a wide range of parameters. The transition to the convecting state occurs without hysteresis when the amplitude of the plate acceleration exceeds a critical value. We find that a non-dimensional stress, the stress due to the inertia of the fluid normalized by the yield stress, governs the onset of the convective motion.

  17. Energy transport using natural convection boundary layers

    SciTech Connect (OSTI)

    Anderson, R.

    1986-04-01T23:59:59.000Z

    Natural convection is one of the major modes of energy transport in passive solar buildings. There are two primary mechanisms for natural convection heat transport through an aperture between building zones: (1) bulk density differences created by temperature differences between zones; and (2) thermosyphon pumping created by natural convection boundary layers. The primary objective of the present study is to compare the characteristics of bulk density driven and boundary layer driven flow, and discuss some of the advantages associated with the use of natural convection boundary layers to transport energy in solar building applications.

  18. 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.

  19. Mesoscale Atmospheric Dispersion, 2001, Ed. Z. Boybeyi, WIT Publications, Southampton, UK, Advances in Air Pollution, Vol 9, p. 424.

    E-Print Network [OSTI]

    Raman, Sethu

    surface­atmosphere exchanges in mesoscale air pollution systems Devdutta S. Niyogi & Sethu Raman NorthMesoscale Atmospheric Dispersion, 2001, Ed. Z. Boybeyi, WIT Publications, Southampton, UK, Advances in Air Pollution, Vol 9, p. 424. Chapter 9 Numerical modeling of gas deposition and bi- directional

  20. Development and Evaluation of a Coupled Photosynthesis-Based Gas Exchange Evapotranspiration Model (GEM) for Mesoscale Weather Forecasting Applications

    E-Print Network [OSTI]

    Niyogi, Dev

    Development and Evaluation of a Coupled Photosynthesis-Based Gas Exchange Evapotranspiration Model (GEM) for Mesoscale Weather Forecasting Applications DEV NIYOGI Department of Agronomy, and Department form 13 May 2008) ABSTRACT Current land surface schemes used for mesoscale weather forecast models use

  1. Slide 1Falk Herwig7 Aug 2006 Convective and non-convective mixing

    E-Print Network [OSTI]

    Herwig, Falk

    Slide 1Falk Herwig7 Aug 2006 Convective and non-convective mixing in AGB stars Falk Herwig and Bernd Freytag Los Alamos National Laboratory Theoretical Astrophysics Group #12;Slide 2Falk Herwig7 Aug envelope models for sun-like stars #12;Slide 3Falk Herwig7 Aug 2006 3D hydro simulations of AGB convective

  2. Utilizing CLASIC observations and multiscale models to study the impact of improved Land surface representation on modeling cloud- convection

    SciTech Connect (OSTI)

    Niyogi, Devdutta S. [Purdue

    2013-06-07T23:59:59.000Z

    The CLASIC experiment was conducted over the US southern great plains (SGP) in June 2007 with an objective to lead an enhanced understanding of the cumulus convection particularly as it relates to land surface conditions. This project was design to help assist with understanding the overall improvement of land atmosphere convection initiation representation of which is important for global and regional models. The study helped address one of the critical documented deficiency in the models central to the ARM objectives for cumulus convection initiation and particularly under summer time conditions. This project was guided by the scientific question building on the CLASIC theme questions: What is the effect of improved land surface representation on the ability of coupled models to simulate cumulus and convection initiation? The focus was on the US Southern Great Plains region. Since the CLASIC period was anomalously wet the strategy has been to use other periods and domains to develop the comparative assessment for the CLASIC data period, and to understand the mechanisms of the anomalous wet conditions on the tropical systems and convection over land. The data periods include the IHOP 2002 field experiment that was over roughly same domain as the CLASIC in the SGP, and some of the DOE funded Ameriflux datasets.

  3. Realistic Solar Convection Simulations Robert F. Stein

    E-Print Network [OSTI]

    Stein, Robert

    Realistic Solar Convection Simulations Robert F. Stein Michigan State University, East Lansing, MIAFG, Juliane Maries Vej 30, Dk¬≠2100 Copenhagen √?, Denmark Abstract. We report on realistic simulations of solar and intensity spectra, the p¬≠mode excitation rate, and the depth of the convection zone. We describe how solar

  4. Collective phase description of oscillatory convection

    SciTech Connect (OSTI)

    Kawamura, Yoji, E-mail: ykawamura@jamstec.go.jp [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan)] [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan); Nakao, Hiroya [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)] [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)

    2013-12-15T23:59:59.000Z

    We formulate a theory for the collective phase description of oscillatory convection in Hele-Shaw cells. It enables us to describe the dynamics of the oscillatory convection by a single degree of freedom which we call the collective phase. The theory can be considered as a phase reduction method for limit-cycle solutions in infinite-dimensional dynamical systems, namely, stable time-periodic solutions to partial differential equations, representing the oscillatory convection. We derive the phase sensitivity function, which quantifies the phase response of the oscillatory convection to weak perturbations applied at each spatial point, and analyze the phase synchronization between two weakly coupled Hele-Shaw cells exhibiting oscillatory convection on the basis of the derived phase equations.

  5. Ocean dynamics and thermodynamics in the tropical Indo- Pacific region

    E-Print Network [OSTI]

    Drushka, Kyla

    2011-01-01T23:59:59.000Z

    Pacific Oceans . . . . . . . . . . . . . . . . . . . . . . . . . . . . .currents in the tropical Pacific Ocean. J. Phys. Oceanogr. ,in the eastern tropical Pacific Ocean associated with the

  6. Mesoscale modelling for an offshore wind farm Jake Badger*, Rebecca Barthelmie, Sten Frandsen, Merete Bruun Christiansen

    E-Print Network [OSTI]

    Mesoscale modelling for an offshore wind farm Jake Badger*, Rebecca Barthelmie, Sten Frandsen for an offshore wind farm in a coastal location. Spatial gradients and vertical profiles between 25 m and 70 m offshore wind farms tend to be placed within the coastal zone, the region within around 50km from

  7. Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data

    E-Print Network [OSTI]

    Reich, Brian J.

    Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data Montserrat fields. Doppler radar data offer better spatial and temporal coverage, but Doppler radar measures values. We use spatial logistic regression to model the probability of rain for both sources of data

  8. Modeling of mesoscale coupled oceanatmosphere interaction and its feedback to ocean in the western Arabian Sea

    E-Print Network [OSTI]

    Jochum, Markus

    -term in situ measurements. Given the shallow mixed layer, this additional surface heat flux warms the cold of the ocean. The observed relationship between the near-surface winds and mesoscale SSTs generate Ekman pump- ing velocities at the scale of the cold filaments, whose magnitude is the order of 1 m/day in both

  9. Larval fish assemblages and mesoscale oceanographic structure along the Mesoamerican Barrier Reef System

    E-Print Network [OSTI]

    Larval fish assemblages and mesoscale oceanographic structure along the Mesoamerican Barrier Reef Caribbean region, and contains spawning sites for a number of reef fish species. Despite this, little is known of the distribution and transport of pelagic fish larvae in the area, and basic in situ

  10. Temporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction

    E-Print Network [OSTI]

    Knievel, Jason Clark

    a method of evaluating numerical weather prediction models by comparing the characteristics of temporal for biases in features forecast by the model. 1. Introduction Verification of numerical weather predictionTemporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction DARAN L

  11. Combustion in Meso-scale Vortex Chambers Ming-hsun Wu*

    E-Print Network [OSTI]

    Yang, Vigor

    %. For propane/air combustion, the stability limits ranged from ~ 0.25 to 2 for the 124 mm3 combustor. Methane of a small combustor not only makes the heat generated from the combustion process hard to keep pace1 Combustion in Meso-scale Vortex Chambers Ming-hsun Wu* , Yanxing Wang, Vigor Yang and Richard A

  12. Midlevel Ventilation's Constraint on Tropical Cyclone Intensity

    E-Print Network [OSTI]

    Tang, Brian Hong-An

    Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a tropical cycloneís intensity. An ...

  13. Elements of tropical Pacific decadal variability

    E-Print Network [OSTI]

    Fuckar, Neven-Stjepan

    2003-01-01T23:59:59.000Z

    potential to change the background state of the eastern tropical Pacific. Simultaneously, a redistribution of atmospheric vorticity in the western tropical Pacific affects isopycnal depth and therefore ocean thermal structure progressing the decadal change...

  14. Coupling a Mesoscale Numerical Weather Prediction Model with Large-Eddy Simulation for Realistic Wind Plant Aerodynamics Simulations (Poster)

    SciTech Connect (OSTI)

    Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.

    2014-06-01T23:59:59.000Z

    Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.

  15. Tropical Fruit Ambrosia Makes 6 servings

    E-Print Network [OSTI]

    Florida, University of

    Tropical Fruit Ambrosia Makes 6 servings 1 jar (26 oz.) mixed tropical fruit, drained 1 large coconut Lettuce leaves Directions: 1. In a large bowl, combine the tropical fruit and banana. 2. In a small bowl, stir together the yogurt, lime zest, and lime juice until blended. 3. Spoon over the fruit

  16. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-01-01T23:59:59.000Z

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  17. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-11-01T23:59:59.000Z

    Natural convection between spaces in a building which play a major role in energy transfer are discussed. Two situations are investigated: Convection through a single doorway into a remote room, and a convective loop in a two story house with a south sunspace where a north stairway serves as the return path. A doorway sizing equation is given for the single door case. Data from airflow monitoring in one two-story house and summary data for five others are presented. The nature of the airflow and design guidelines are presented.

  18. Convective Cooling and Passive Stack Improvements in Motors (Presentation)

    SciTech Connect (OSTI)

    Bennion, K.

    2014-06-01T23:59:59.000Z

    This presentation discusses current research at NREL in convective cooling and passive stack improvements in motors.

  19. Estimation of Convection Loss from Paraboloidal Dish Cavity Receivers

    E-Print Network [OSTI]

    presents new results from an investigation of natural and combined convection heat transfer from open in which force convection dominates can be clarified. 1. INTRODUCTION Convective heat transfer and numerical investigation of natural convection heat transfer has also been published in Taumoefolau et al

  20. 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.

  1. Tropical rainforest biodiversity: field and

    E-Print Network [OSTI]

    . The Udzungwas in particular, are one of the single, most important areas in Africa for biodiversity conservationTropical rainforest biodiversity: field and GIS tools for assessing, monitoring and mapping II with Tanzania National ParksTanzania National Parks andand Wildlife Conservation SocietyWildlife Conservation

  2. Modeling convection in the Greenland Sea

    E-Print Network [OSTI]

    Bhushan, Vikas

    1998-01-01T23:59:59.000Z

    A detailed examination of the development of a deep convection event observed in the Greenland Sea in 1988-89 is carried out through a combination of modeling, scale estimates, and data analysis. We develop a prognostic ...

  3. Circulation and convection in the Irminger Sea

    E-Print Network [OSTI]

    VŚge, Kjetil

    2010-01-01T23:59:59.000Z

    Aspects of the circulation and convection in the Irminger Sea are investigated using a variety of in-situ, satellite, and atmospheric reanalysis products. Westerly Greenland tip jet events are intense, small-scale wind ...

  4. Seismic Sounding of Convection in the Sun

    E-Print Network [OSTI]

    Hanasoge, Shravan; Sreenivasan, Katepalli R

    2015-01-01T23:59:59.000Z

    Our Sun, primarily composed of ionized hydrogen and helium, has a surface temperature of 5777~K and a radius $R_\\odot \\approx 696,000$ km. In the outer $R_\\odot/3$, energy transport is accomplished primarily by convection. Using typical convective velocities $u\\sim100\\,\\rm{m\\,s^{-1}}$ and kinematic viscosities of order $10^{-4}$ m$^{2}$s$^{-1}$, we obtain a Reynolds number $Re \\sim 10^{14}$. Convection is thus turbulent, causing a vast range of scales to be excited. The Prandtl number, $Pr$, of the convecting fluid is very low, of order $10^{-7}$\\,--\\,$10^{-4}$, so that the Rayleigh number ($\\sim Re^2 Pr$) is on the order of $10^{21}\\,-\\,10^{24}$. Solar convection thus lies in extraordinary regime of dynamical parameters, highly untypical of fluid flows on Earth. Convective processes in the Sun drive global fluid circulations and magnetic fields, which in turn affect its visible outer layers ("solar activity") and, more broadly, the heliosphere ("space weather"). The precise determination of the depth of sola...

  5. A Satellite Study of Tropical Moist Convection and Environmental Variability: A Moisture and Thermal Budget Analysis

    E-Print Network [OSTI]

    Masunaga, Hirohiko

    radiometer and scatterometer aboard different platforms. Satellite measurements of atmospheric parameters of moisture and dry static energy and their vertical flux at cloud base from satellite observations alone convergence for highly organized systems; 2) FT diabatic heating is largely offset on an instantaneous basis

  6. Retrieval of Hydrometeor Profiles in Tropical Cyclones and Convection from Combined Radar and Radiometer Observations

    E-Print Network [OSTI]

    Jiang, Haiyan

    of understanding the global energy and water cycles by providing four-dimensional distributions of latent heat- ing related to latent heating, ice water content (IWC) and liquid water content (LWC) have implications A retrieval algorithm is described to estimate vertical profiles of precipitation ice water content and liquid

  7. Intersecting Cold Pools: Convective Cloud Organization by Cold Pools over Tropical Ocean

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformation for and Application deadline: November

  8. 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.

  9. Mesoscale fracture fabric and paleostress along the San Andreas fault at SAFOD

    E-Print Network [OSTI]

    Almeida, Rafael Vladimir

    2009-05-15T23:59:59.000Z

    Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Judith Chester Committee Members, Frederick Chester David Schechter Head of Department... of Advisory Committee: Dr. Judith Chester Spot cores from Phase 1 drilling of the main borehole at the San Andreas Fault Observatory at Depth (SAFOD) were mapped to characterize the mesoscale structure and infer paleostress at depth. Cores were oriented...

  10. Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation

    E-Print Network [OSTI]

    Meng, Zhiyong

    2007-09-17T23:59:59.000Z

    technique with real observations (Houtekamer et al. 2005; Whitaker et al. 2006). However, the performance of the EnKF implemented in mesoscale models has not been compared directly to that of variational method. ____________ This dissertation follows... while perturbing the observation. However, the computation cost is very large when applying this method to high-degree- of-freedom systems. Whitaker and Hamill (2002) introduced the ensemble square-root filter (EnSRF) as a better way to deal...

  11. Representation of the mesoscale wind field using a line integral technique

    E-Print Network [OSTI]

    Trares, John S

    1982-01-01T23:59:59.000Z

    REPPESENTATION OF THE MESOSCALE WIND FIELD USING A LINE INTEGRAL TECHNII1UE A Thesis by JOHN SEBASTIAN TRARES, JR. Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1982 Major Subject: Meteorology REPRESENTATION OF THE HESOSCALE WIND FIELD USING A LINE INTEGRAL TECHNIQUE A Thesis by JOHN SESASTIAN TRARES, JR. Approved as to style and content by: Chairman of Committee Nember ember Head of Depar...

  12. Mesoscale phenomena in solutions of 3-methylpyridine, heavy water, and an antagonistic salt

    E-Print Network [OSTI]

    Jan Leys; Deepa Subramanian; Eva Rodezno; Boualem Hammouda; Mikhail A. Anisimov

    2013-08-22T23:59:59.000Z

    We have investigated controversial issues regarding the mesoscale behavior of 3-methylpyridine (3MP), heavy water, and sodium tetraphenylborate (NaBPh4) solutions by combining results obtained from dynamic light scattering (DLS) and small-angle neutron scattering (SANS). We have addressed three questions: (i) what is the origin of the mesoscale inhomogeneities (order of 100 nm in size) manifested by the "slow mode" in DLS? (ii) Is the periodic structure observed from SANS an inherent property of this system? (iii) What is the universality class of critical behavior in this system? Our results confirm that the "slow mode" observed from DLS experiments corresponds to long-lived, highly stable mesoscale droplets (order of 100 nm in size), which occur only when the solute (3MP) is contaminated by hydrophobic impurities. SANS data confirm the presence of a periodic structure with a periodicity of about 10 nm. This periodic structure cannot be eliminated by nanopore filtration and thus is indeed an inherent solution property. The critical behavior of this system, in the range of concentration and temperatures investigated by DLS experiments, indicates that the criticality belongs to the universality class of the 3-dimensional Ising model.

  13. Ecotoxicology of tropical marine ecosystems

    SciTech Connect (OSTI)

    Peters, E.C. [Tetra Tech, Inc., Fairfax, VA (United States); Gassman, N.J.; Firman, J.C. [Univ. of Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Richmond, R.H. [Univ. of Guam, Mangilao (Guam). Marine Lab.; Power, E.A. [EVS Environment Consultants, Ltd., North Vancouver, British Columbia (Canada)

    1997-01-01T23:59:59.000Z

    The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

  14. On the Diurnal Cycle of Deep Convection, High-Level Cloud, and Upper Troposphere Water Vapor in the Multiscale Modeling Framework

    SciTech Connect (OSTI)

    Zhang, Yunyan; Klein, Stephen A.; Liu, Chuntao; Tian, Baijun; Marchand, Roger T.; Haynes, J. M.; McCoy, Renata; Zhang, Yuying; Ackerman, Thomas P.

    2008-08-22T23:59:59.000Z

    The Multiscale Modeling Framework (MMF), also called ĎĎsuperparameterizationíí, embeds a cloud-resolving model (CRM) at each grid column of a general circulation model to replace traditional parameterizations of moist convection and large-scale condensation. This study evaluates the diurnal cycle of deep convection, high-level clouds, and upper troposphere water vapor by applying an infrared (IR) brightness temperature (Tb) and a precipitation radar (PR) simulator to the CRM column data. Simulator results are then compared with IR radiances from geostationary satellites and PR reflectivities from the Tropical Rainfall Measuring Mission (TRMM). While the actual surface precipitation rate in the MMF has a reasonable diurnal phase and amplitude when compared with TRMM observations, the IR simulator results indicate an inconsistency in the diurnal anomalies of high-level clouds between the model and the geostationary satellite data. Primarily because of its excessive high-level clouds, the MMF overestimates the simulated precipitation index (PI) and fails to reproduce the observed diurnal cycle phase relationships among PI, high-level clouds, and upper troposphere relative humidity. The PR simulator results show that over the tropical oceans, the occurrence fraction of reflectivity in excess of 20 dBZ is almost 1 order of magnitude larger than the TRMM data especially at altitudes above 6 km. Both results suggest that the MMF oceanic convection is overactive and possible reasons for this bias are discussed. However, the joint distribution of simulated IR Tb and PR reflectivity indicates that the most intense deep convection is found more often over tropical land than ocean, in agreement with previous observational studies.

  15. Asteroseismic Diagnostics of Stellar Convective Cores

    E-Print Network [OSTI]

    Anwesh Mazumdar; Sarbani Basu; Braxton L. Collier; Pierre Demarque

    2006-08-16T23:59:59.000Z

    We present a detailed study of the small frequency separations as diagnostics of the mass of the convective core and evolutionary stage of solar-type stars. We demonstrate how the small separations can be combined to provide sensitive tests for the presence of convective overshoot at the edge of the core. These studies are focused on low degree oscillation modes, the only modes expected to be detected in distant stars. Using simulated data with realistic errors, we find that the mass of the convective core can be estimated to within 5% if the total stellar mass is known. Systematic errors arising due to uncertainty in the mass could be up to 20%. The evolutionary stage of the star, determined in terms of the central hydrogen abundance using our proposed technique, however, is much less sensitive to the mass estimate.

  16. The Role of the Tropics in Abrupt Climate Changes

    SciTech Connect (OSTI)

    Fedorov, Alexey [Yale University] [Yale University

    2013-12-07T23:59:59.000Z

    Topics addressed include: abrupt climate changes and ocean circulation in the tropics; what controls the ocean thermal structure in the tropics; a permanent El NiŮo in paleoclimates; the energetics of the tropical ocean.

  17. Influence of Tropical Tropopause Layer Cooling on Atlantic Hurricane Activity

    E-Print Network [OSTI]

    Solomon, Susan

    Virtually all metrics of Atlantic tropical cyclone activity show substantial increases over the past two decades. It is argued here that cooling near the tropical tropopause and the associated decrease in tropical cyclone ...

  18. Origins of convective activity over Panama

    E-Print Network [OSTI]

    Strager, Christopher Stephen

    1989-01-01T23:59:59.000Z

    Satellite-derived outgoing longwave radiation (OLR) data. were used to examine convective variability over the Panama region. Time series analysis of the area- averaged daily OLR data, for 1984 and 1985 revealed a, persistent 12-d oscillation... in convective activity during each season. Composite analyses of OLR data, for the area 120'W-40'W and 35'S-35'N for the 1984 dry (1 January ? 9 May) and wet (10 Msy? 4 December) seasons showed this oscillation extends beyond Panama and the Central America...

  19. Convection and dynamo action in B stars

    E-Print Network [OSTI]

    Augustson, Kyle C; Toomre, Juri

    2010-01-01T23:59:59.000Z

    Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to model turbulent dynamics within a 10 solar mass main-sequence (MS) B-type star rotating at 4 times the solar rate. We find that strong (900 kG) magnetic fields arise within the turbulence of the core and penetrate into the stably stratified radiative zone. These fields exhibit complex, time-dependent behavior including reversals in magnetic polarity and shifts between which hemisphere dominates the total magnetic energy.

  20. Analysis of tropical radiative heating profiles: A comparison...

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

    tropical radiative heating profiles: A comparison of models and observations . Analysis of tropical radiative heating profiles: A comparison of models and observations . Abstract:...

  1. Characterization of Trapped Lignin-Degrading Microbes in Tropical...

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

    Trapped Lignin-Degrading Microbes in Tropical Forest Soil. Characterization of Trapped Lignin-Degrading Microbes in Tropical Forest Soil. Abstract: Lignin is often the most...

  2. Simulation of Convection and Macrosegregation in a Large Steel Ingot

    E-Print Network [OSTI]

    Beckermann, Christoph

    Simulation of Convection and Macrosegregation in a Large Steel Ingot J.P. GU and C. BECKERMANN Melt convection and macrosegregation in casting of a large steel ingot are numerically simulated. The simulation is based on a previously developed model for multicomponent steel solidification with melt convection

  3. Realistic Solar Surface Convection Simulations Robert F. Stein

    E-Print Network [OSTI]

    Stein, Robert

    Realistic Solar Surface Convection Simulations Robert F. Stein Michigan State University, East free simulations with re­ alistic physics of convection near the solar surface. We summarize solar convection is non­local. It is driven from a thin surface thermal boundary layer where radiative

  4. Tropical Western Pacific CART Site

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2TopoPortalBRDF Effects inHeterogeneousTropical

  5. ORIGINAL ARTICLE Mitigation needs adaptation: Tropical forestry

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ORIGINAL ARTICLE Mitigation needs adaptation: Tropical forestry and climate change Manuel R adapt to this change. This paper discusses how tropical forestry practices can contribute to maintaining Forestry Research, P.O. Box 6596 JKPWB, Jakarta 10065, Indonesia e-mail: m.guariguata@cgiar.org J. P

  6. The effect of convection on pulsational stability

    E-Print Network [OSTI]

    G. Houdek

    2008-10-29T23:59:59.000Z

    A review on the current state of mode physics in classical pulsators is presented. Two, currently in use, time-dependent convection models are compared and their applications on mode stability are discussed with particular emphasis on the location of the Delta Scuti instability strip.

  7. Laminar boundary layers in convective heat transport

    E-Print Network [OSTI]

    Christian Seis

    2012-12-12T23:59:59.000Z

    We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which can be used to control the fluid motion in the layer. The bounds on the temperature field are derived with the help of local maximal regularity estimates for convection-diffusion equations.

  8. Convective Instability of a Boundary Layer with

    E-Print Network [OSTI]

    Conrad, Clint

    proportional to the integral over the depth of the lithosphere of the 19 #12;ratio of thermal buoyancy. Such instabilities are driven by the negative thermal buoyancy of the cold lithosphere and retarded largely for driving convective downwelling. For non-Newtonian viscosity with power law exponent n and temperature

  9. Solar Dynamics, Rotation, Convection and Overshoot

    E-Print Network [OSTI]

    Hanasoge, S; Roth, M; Schou, J; Schuessler, M; Thompson, M J

    2015-01-01T23:59:59.000Z

    We discuss recent observational, theoretical and modeling progress made in understanding the Sun's internal dynamics, including its rotation, meridional flow, convection and overshoot. Over the past few decades, substantial theoretical and observational effort has gone into appreciating these aspects of solar dynamics. A review of these observations, related helioseismic methodology and inference and computational results in relation to these problems is undertaken here.

  10. Convective and absolute instabilities in eccentric Taylor

    E-Print Network [OSTI]

    Shyamasundar, R.K.

    Convective and absolute instabilities in eccentric Taylor Laboratoire de m√©canique des fluides et d and absolute instabilities in Taylor-Couette-Poiseuille flow Beno√ģt PIER Laboratoire de m√©canique des fluides flow type often disrupt oil-well drilling By implementing a detailed instability analysis, the dynamics

  11. Solar MagnetoConvection David J. Bercik

    E-Print Network [OSTI]

    Stein, Robert

    Solar Magneto¬≠Convection David J. Bercik Dept. of Physics and Astronomy, Michigan State University, Michigan State University, East Lansing, MI 48824, U.S.A. Ň° Ake Nordlund Theoretical Astrophysics Center, √?ster Voldgade 3, 1350 Copenhagen K, Denmark Robert F. Stein Dept. of Physics and Astronomy, Michigan

  12. Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton, Roger M. Samelson, Michael G. Schlax, Larry W. O'Neill2

    E-Print Network [OSTI]

    Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies temperature (SST) field, which generates a stress curl and therefore Ekman pumping in regions of crosswind SST

  13. Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton, Roger M. Samelson, Michael G. Schlax, Larry W. O'Neill2

    E-Print Network [OSTI]

    Samelson, Roger

    Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies generates a curl of the stress and therefore Ekman pumping in regions of crosswind SST gradients

  14. ARCHITECTURE OF THE MERCURY MESOSCALE METEOROLOGICAL DATA FUSION C. Fields, C. Cavendish, M. Coombs, T. Eskridge, R. Hartley, H. Pfeiffer, and C. Soderlund

    E-Print Network [OSTI]

    Hartley, Roger

    ARCHITECTURE OF THE MERCURY MESOSCALE METEOROLOGICAL DATA FUSION C. Fields, C. Cavendish, M. Coombs Atmospheric Sciences Laboratory White Sands Missile Range, NM 88002-5501 USA 1. INTRODUCTION The MERCURY) that require meteorological data as input (McWilliams or al., this volume). MERCURY addresses, at the mesoscale

  15. CONVECTION THEORY AND SUB-PHOTOSPHERIC STRATIFICATION

    SciTech Connect (OSTI)

    Arnett, David; Meakin, Casey; Young, Patrick A., E-mail: darnett@as.arizona.ed, E-mail: casey.meakin@gmail.co, E-mail: patrick.young.1@asu.ed [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2010-02-20T23:59:59.000Z

    As a preliminary step toward a complete theoretical integration of three-dimensional compressible hydrodynamic simulations into stellar evolution, convection at the surface and sub-surface layers of the Sun is re-examined, from a restricted point of view, in the language of mixing-length theory (MLT). Requiring that MLT use a hydrodynamically realistic dissipation length gives a new constraint on solar models. While the stellar structure which results is similar to that obtained by Yale Rotational Evolution Code (Guenther et al.; Bahcall and Pinsonneault) and Garching models (Schlattl et al.), the theoretical picture differs. A new quantitative connection is made between macro-turbulence, micro-turbulence, and the convective velocity scale at the photosphere, which has finite values. The 'geometric parameter' in MLT is found to correspond more reasonably with the thickness of the superadiabatic region (SAR), as it must for consistency in MLT, and its integrated effect may correspond to that of the strong downward plumes which drive convection (Stein and Nordlund), and thus has a physical interpretation even in MLT. If we crudely require the thickness of the SAR to be consistent with the 'geometric factor' used in MLT, there is no longer a free parameter, at least in principle. Use of three-dimensional simulations of both adiabatic convection and stellar atmospheres will allow the determination of the dissipation length and the geometric parameter (i.e., the entropy jump) more realistically, and with no astronomical calibration. A physically realistic treatment of convection in stellar evolution will require substantial additional modifications beyond MLT, including nonlocal effects of kinetic energy flux, entrainment (the most dramatic difference from MLT found by Meakin and Arnett), rotation, and magnetic fields.

  16. Numerical simulations of mesoscale precipitation systems. Final progress report, 1 April-30 June 1981

    SciTech Connect (OSTI)

    Dingle, A.N.

    1982-05-12T23:59:59.000Z

    A numerical model designed for the study of mesoscale weather phenomena is presented. It is a three-dimensional, time-dependent model based upon a mesoscale primitive-equation system, and it includes parameterizations of cloud and precipitation processes, boundary-layer transfers, and ground surface energy and moisture budgets. This model was used to simulate the lake-effect convergence over and in the lee of Lake Michigan in late fall and early winter. The lake-effect convergence is created in advected cold air as it moves first from cold land to the warm constant-temperature lake surface, and then on to cold land. A numerical experiment with a prevailing northwesterly wind is conducted for a period of twelve hours. Two local maxima of the total precipitation are observed along the eastern shore of Lake Michigan. The results in this hypothetical case correspond quite well to the observed precipitation produced by a real event in which the hypothetical conditions are approximately fulfilled.

  17. Thermocapillary convection induced by laser surface heating

    SciTech Connect (OSTI)

    Gladush, G G; Drobyazko, S V; Likhanskii, V V; Loboiko, A I; Senatorov, Yu M [State Research Center of Russian Federation 'Troitsk Institute for Innovation and Fusion Research', Troitsk, Moscow Region (Russian Federation)

    1998-05-31T23:59:59.000Z

    Thermocapillary convection was excited by a laser source in experiments on molten paraffin. The parameters of the resultant flow were determined. The nature of the flow was demonstrated to correspond to shear-driven boundary-layer flow at high Reynolds numbers. Correlation dependences of the flow velocity of the melt and its temperature in the surface region were derived theoretically and were shown to agree with the experimental results. When the size of the laser spot was much less than the characteristic convection scales, three regions of flow of the melt could be distinguished: a viscous surface boundary layer, a stagnation zone under the laser spot, and a large-scale region of flow with a homogeneous temperature distribution. (interaction of laser radiation with matter. laser plasma)

  18. Laser induced natural convection and thermophoresis

    SciTech Connect (OSTI)

    Wang, C.Y.; Cipolla, J.; Morse, T.F.

    1983-07-01T23:59:59.000Z

    The influence of axial laser volumetric heating and forced convection on the motion of aerosol particles in a vertical tube has been studied. The asymptotic case of constant wall temperature provides simple temperature and velocity profiles that determine the convection and thermophoretic motion of small aerosol particles. For the case in which the flow (in the absence of laser heating) is downward, the laser heating induces upward buoyant motion near the tube center. When the laser heating is taken to be constant (a small absorption limit), a velocity profile may be found that will minimize the distance over which particles are deposited on the wall. Such an observation may have some bearing on the manufacture of preforms from which optical fibers are drawn.

  19. Magneto-convection in a sunspot umbra

    E-Print Network [OSTI]

    M. Schuessler; A. Voegler

    2006-03-03T23:59:59.000Z

    Results from a realistic simulation of 3D radiative magneto-convection in a strong background magnetic field corresponding to the conditions in sunspot umbrae are shown. The convective energy transport is dominated by narrow upflow plumes with adjacent downflows, which become almost field-free near the surface layers. The strong external magnetic field forces the plumes to assume a cusp-like shape in their top parts, where the upflowing plasma loses its buoyancy. The resulting bright features in intensity images correspond well (in terms of brightness, size, and lifetime) to the observed umbral dots in the central parts of sunspot umbrae. Most of the simulated umbral dots have a horizontally elongated form with a central dark lane. Above the cusp, most plumes show narrow upflow jets, which are driven by the pressure of the piled-up plasma below. The large velocities and low field strengths in the plumes are effectively screened from spectroscopic observation because the surfaces of equal optical depth are locally elevated, so that spectral lines are largely formed above the cusp. Our simulations demonstrate that nearly field-free upflow plumes and umbral dots are a natural result of convection in a strong, initially monolithic magnetic field.

  20. Convective Dynamo Simulation with a Grand Minimum

    E-Print Network [OSTI]

    Augustson, Kyle; Miesch, Mark; Toomre, Juri

    2015-01-01T23:59:59.000Z

    The global-scale dynamo action achieved in a simulation of a Sun-like star rotating at thrice the solar rate is assessed. The 3-D MHD Anelastic Spherical Harmonic (ASH) code, augmented with a viscosity minimization scheme, is employed to capture convection and dynamo processes in this G-type star. The simulation is carried out in a spherical shell that encompasses 3.8 density scale heights of the solar convection zone. It is found that dynamo action with a high degree of time variation occurs, with many periodic polarity reversals occurring roughly every 6.2 years. The magnetic energy also rises and falls with a regular period. The magnetic energy cycles arise from a Lorentz-force feedback on the differential rotation, whereas the processes leading to polarity reversals are more complex, appearing to arise from the interaction of convection with the mean toroidal fields. Moreover, an equatorial migration of toroidal field is found, which is linked to the changing differential rotation, and potentially to a no...

  1. Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale catchments in Luxembourg

    E-Print Network [OSTI]

    Kirchner, James W.

    Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale September 2012; published 10 October 2012. [1] The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner

  2. Tests of an Ensemble Kalman Filter for Mesoscale and Regional-Scale Data Assimilation. Part II: Imperfect Model Experiments

    E-Print Network [OSTI]

    Meng, Zhiyong

    degraded). As in Part I, where the perfect model assumption was utilized, most analysis error reduction of significant model errors due to physical parameterizations by assimilating synthetic sounding and surfaceTests of an Ensemble Kalman Filter for Mesoscale and Regional-Scale Data Assimilation. Part II

  3. Mesoscale Self-Assembly: Capillary Bonds and Negative Menisci Ned Bowden, Scott R. J. Oliver, and George M. Whitesides*

    E-Print Network [OSTI]

    Prentiss, Mara

    Mesoscale Self-Assembly: Capillary Bonds and Negative Menisci Ned Bowden, Scott R. J. Oliver., Cambridge, Massachusetts 02138 ReceiVed: September 2, 1999 This paper describes the self-assembly) that examined the self-assembly of hexagonal plates of PDMS (F ) 1.05 g/cm3) that had a density close

  4. Midlevel ventilation's constraint on tropical cyclone intensity

    E-Print Network [OSTI]

    Tang, Brian Hong-An

    2010-01-01T23:59:59.000Z

    Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a TC's intensity. An idealized ...

  5. Meridional Circulation in Solar and Stellar Convection Zones

    E-Print Network [OSTI]

    Featherstone, Nicholas A

    2015-01-01T23:59:59.000Z

    We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code, that are designed to isolate those processes that drive and shape meridional circulations within stellar convection zones. These simulations have been constructed so as to span the transition between solar-like differential rotation (fast equator/slow poles) and ``anti-solar' differential rotation (slow equator/fast poles). Solar-like states of differential rotation, arising when convection is rotationally constrained, are characterized by a very different convective Reynolds stress than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective Reynolds stress plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled meridional circulation profiles in strong and weak regimes of rotational constraint is lin...

  6. On the connection between continental-scale land surface processes and the tropical climate in a coupled ocean-atmosphere-land system

    SciTech Connect (OSTI)

    Ma, Hsi-Yen; Mechoso, C. R.; Xue, Yongkang; Xiao, Heng; Neelin, David; Ji, Xuan

    2013-11-15T23:59:59.000Z

    The impact of global tropical climate to perturbations in land surface processes (LSP) are evaluated using perturbations given by different LSP representations of continental-scale in a global climate model that includes atmosphere-ocean interactions. One representation is a simple land scheme, which specifies climatological albedos and soil moisture availability. The other representation is the more comprehensive Simplified Simple Biosphere Model, which allows for interactive soil moisture and vegetation biophysical processes. The results demonstrate that LSP processes such as interactive soil moisture and vegetation biophysical processes have strong impacts on the seasonal mean states and seasonal cycles of global precipitation, clouds, and surface air temperature. The impact is especially significant over the tropical Pacific. To explore the mechanisms for such impact, different LSP representations are confined to selected continental-scale regions where strong interactions of climate-vegetation biophysical processes are present. We find that the largest impact is mainly from LSP perturbations over the tropical African continent. The impact is through anomalous convective heating in tropical Africa due to changes in the surface heat fluxes, which in turn affect basinwide teleconnections in the Pacific through equatorial wave dynamics. The modifications in the equatorial Pacific climate are further enhanced by strong air-sea coupling between surface wind stress and upwelling, as well as effect of ocean memory. Our results further suggest that correct representations of land surface processes, land use change and the associated changes in the deep convection over tropical Africa are crucial to reducing the uncertainty when performing future climate projections under different climate change scenarios.

  7. Increase in the Intensity of Postmonsoon Bay of Bengal Tropical Cyclones

    SciTech Connect (OSTI)

    Balaguru, Karthik; Taraphdar, Sourav; Leung, Lai-Yung R.; Foltz, Gregory R.

    2014-05-28T23:59:59.000Z

    The post-monsoon (October-November) tropical cyclone (TC) season in the Bay of Bengal has spawned many of the deadliest storms in recorded history. Here it is shown that the intensity of post-monsoon Bay of Bengal TCs, and the contribution of major TCs to total TC power, increased during 1981-2010. It is found that changes in environmental parameters are responsible for the observed increases in TC intensity. Increases in sea surface temperature and upper ocean heat content made the ocean more conducive to TC development, while enhanced convective instability made the atmosphere more favorable for the growth of TCs. The largest changes in the atmosphere and ocean occurred in the eastern Bay of Bengal, where nearly all major TCs form. These changes are part of positive linear trends, suggesting that the intensity of post-monsoon Bay of Bengal TCs may continue to increase in the future.

  8. Influence of the tropical Atlantic versus the tropical Pacific on Caribbean rainfall

    E-Print Network [OSTI]

    Influence of the tropical Atlantic versus the tropical Pacific on Caribbean rainfall Michael A; published 20 September 2002. [1] The Caribbean rainfall season runs from May through November, with positive anomalies over a narrow latitudinal band (0¬į¬≠20¬įN) being associated with enhanced Caribbean

  9. Vortex arrays and meso-scale turbulence of self-propelled particles

    E-Print Network [OSTI]

    Robert Grossmann; Pawel Romanczuk; Markus Bšr; Lutz Schimansky-Geier

    2014-05-30T23:59:59.000Z

    Inspired by the Turing mechanism for pattern formation, we propose a simple self-propelled particle model with short-ranged alignment and anti-alignment at larger distances. It is able to produce orientationally ordered states, periodic vortex patterns as well as meso-scale turbulence. The latter phase resembles observations in dense bacterial suspensions. The model allows a systematic derivation and analysis of a kinetic theory as well as hydrodynamic equations for density and momentum fields. A phase diagram with regions of such pattern formation as well as spatially homogeneous orientational order and disorder is obtained from a linear stability analysis of these continuum equations. Microscopic Langevin simulations of the self-propelled particle system are in agreement with these findings.

  10. Crossing the mesoscale no-mans land via parallel kinetic Monte Carlo.

    SciTech Connect (OSTI)

    Garcia Cardona, Cristina (San Diego State University); Webb, Edmund Blackburn, III; Wagner, Gregory John; Tikare, Veena; Holm, Elizabeth Ann; Plimpton, Steven James; Thompson, Aidan Patrick; Slepoy, Alexander (U. S. Department of Energy, NNSA); Zhou, Xiao Wang; Battaile, Corbett Chandler; Chandross, Michael Evan

    2009-10-01T23:59:59.000Z

    The kinetic Monte Carlo method and its variants are powerful tools for modeling materials at the mesoscale, meaning at length and time scales in between the atomic and continuum. We have completed a 3 year LDRD project with the goal of developing a parallel kinetic Monte Carlo capability and applying it to materials modeling problems of interest to Sandia. In this report we give an overview of the methods and algorithms developed, and describe our new open-source code called SPPARKS, for Stochastic Parallel PARticle Kinetic Simulator. We also highlight the development of several Monte Carlo models in SPPARKS for specific materials modeling applications, including grain growth, bubble formation, diffusion in nanoporous materials, defect formation in erbium hydrides, and surface growth and evolution.

  11. Ocean dynamics and thermodynamics in the tropical Indo- Pacific region

    E-Print Network [OSTI]

    Drushka, Kyla

    2011-01-01T23:59:59.000Z

    The shortwave radiation entering the ocean mixed layer wasocean mixed layer in various ways: convective cells block the incoming solar radiationradiation (71%) that result from anomalous MJO convection. An exception is in the central Indian Ocean and

  12. ARM - Evaluation Product - Convective Vertical Velocity

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcal Documentation(AVIRIS) ProductsAirborne Visible/Infrared Imaging SpectrometerAlgorithmProductsConvective

  13. Natural convection airflow measurement and theory

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.; Yamaguchi, Kenjiro

    1984-01-01T23:59:59.000Z

    Natural convection is a major mechanism for heat distribution in many passive solar buildings, especially those with sunspaces. To better understand this mechanism, observations of air velocities and temperatures have been made in 13 different houses that encompass a wide variety of one- and two-story geometries. This paper extends previous reports. Results from one house are described in detail, and some generalizations are drawn from the large additional mass of data taken. A simple mathematical model is presented that describes the general nature of airflow and energy flow through an aperture.

  14. Air convection noise of pencil-beam interferometer for long trace profiler

    E-Print Network [OSTI]

    Yashchuk, Valeriy V.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Takacs, Peter Z.

    2006-01-01T23:59:59.000Z

    Air Convection Noise of Pencil-beam Interferometer for Longwe investigate the effect of air convection on laser-beamshown that the NPD spectra due to air convection have a very

  15. Seasonal shift in the foraging niche of a tropical avian resident: resource competition at work?

    E-Print Network [OSTI]

    Jedlicka, J A; Greenberg, R; Perfecto, I; Philpottt, S M; Dietsch, T V

    2006-01-01T23:59:59.000Z

    and migrant birds in Campeche, Mexico. Tropical Ecology 22:a dry tropical forest in Campeche, Mexico and found that

  16. Gravity Waves in Shear and Implications for Organized Convection

    E-Print Network [OSTI]

    Stechmann, Samuel N.

    Gravity Waves in Shear and Implications for Organized Convection Samuel N. Stechmann Department, Los Angeles, CA 90095­1555. E-mail: stechmann@math.ucla.edu #12;ABSTRACT It is known that gravity, the gravity waves can create a more favorable environment on one side of preexisting convection than the other

  17. EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE

    E-Print Network [OSTI]

    Stanford University

    EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE A REPORT SUBMITTED between heat conduction and heat convection with boiling flow in a rock fracture. An experimental coefficient. This coefficient is the proportionality factor between the heat flux to a fracture surface

  18. UNCORRECTED Grid geometry effects on convection in ocean climate models

    E-Print Network [OSTI]

    Kuhlbrodt, Till

    UNCORRECTED PROOF Grid geometry effects on convection in ocean climate models: a conceptual study is the 12 improvement of convection parameterization schemes, but the question of grid geometry also plays to an at- 14 mosphere model. Such ocean climate models have mostly structured, coarsely resolved grids. 15

  19. FLUCTUATIONS NEAR THE CONVECTIVE INSTABILITY IN A CHOLESTERIC LIQUID CRYSTAL

    E-Print Network [OSTI]

    Boyer, Edmond

    . For sufficiently strong heating, it is pos- sible for the buoyancy force to overcome the vis- cous shear forces convective pour une certaine valeur critique. A cause du couplage de modes induit par la force extťrieure, la, drives the system into convective instability. It is found that, because of the mode coupling induced

  20. Drainage induced convection rolls in foams (revised version)

    E-Print Network [OSTI]

    Cox, Simon

    , where soap solution is added to the foam at constant flow rate, the irregular motion in the beer glass results for convection in quasi two-dimensional foams (monolayers of bubbles between two glass platesDrainage induced convection rolls in foams (revised version) S. Hutzler, S.J. Cox*, E. Janiaud

  1. Sensitivity of global tropical climate to land surface processes: Mean state and interannual variability

    SciTech Connect (OSTI)

    Ma, Hsi-Yen; Xiao, Heng; Mechoso, C. R.; Xue, Yongkang

    2013-03-01T23:59:59.000Z

    This study examines the sensitivity of global tropical climate to land surface processes (LSP) using an atmospheric general circulation model both uncoupled (with prescribed SSTs) and coupled to an oceanic general circulation model. The emphasis is on the interactive soil moisture and vegetation biophysical processes, which have first order influence on the surface energy and water budgets. The sensitivity to those processes is represented by the differences between model simulations, in which two land surface schemes are considered: 1) a simple land scheme that specifies surface albedo and soil moisture availability, and 2) the Simplified Simple Biosphere Model (SSiB), which allows for consideration of interactive soil moisture and vegetation biophysical process. Observational datasets are also employed to assess the reality of model-revealed sensitivity. The mean state sensitivity to different LSP is stronger in the coupled mode, especially in the tropical Pacific. Furthermore, seasonal cycle of SSTs in the equatorial Pacific, as well as ENSO frequency, amplitude, and locking to the seasonal cycle of SSTs are significantly modified and more realistic with SSiB. This outstanding sensitivity of the atmosphere-ocean system develops through changes in the intensity of equatorial Pacific trades modified by convection over land. Our results further demonstrate that the direct impact of land-atmosphere interactions on the tropical climate is modified by feedbacks associated with perturbed oceanic conditions ("indirect effect" of LSP). The magnitude of such indirect effect is strong enough to suggest that comprehensive studies on the importance of LSP on the global climate have to be made in a system that allows for atmosphere-ocean interactions.

  2. The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean

    SciTech Connect (OSTI)

    Chen, Shu-Hua; Liu, Yi-Chin

    2014-10-27T23:59:59.000Z

    A strong, convective African tropical disturbance has a greater chance to develop into a Tropical 23 Depression (TD) if it merges with a shallow, dry vortex (D-vortex) from the north of the African 24 easterly jet (AEJ) after leaving the western coast. Using 11-year reanalysis data we found that the 25 western tip of a vortex strip at northwestern Africa can serve as dry vortices for the D-vortex 26 merger if it shifts southward. Another source of D-vortices is the westward propagating lows 27 along the southern edge of the Saharan air. The D-vortex merger process occurred for 63.5% of 28 tropical cyclones (TCs) or developing systems over the main development region of the Atlantic 29 Ocean, while it occurred for 54% of non-developing systems. TC genesis could be largely 30 controlled by the large-scale environment, but the differences in characteristics of vortices 31 associated with the D-vortex merger between developing and non-developing systems could 32 potentially help determine their destinies; in general, developing systems were dominated by a 33 more intense and moist south vortex, while non-developing systems were dominated by a north 34 vortex which was more intense, drier, and larger in size. Analysis also shows that 74% of intense 35 developing systems were involved with the D-vortex merger process. More attention needs to be 36 paid to the D-vortex merger and the characteristics of those vortices as they can play significant 37 roles or have a strong indication in Atlantic TC genesis.

  3. WMO/CAS/WWW SEVENTH INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES

    E-Print Network [OSTI]

    Smith, Roger K.

    . As outlined by Dunkerton et al. (2009, hereafter DMW09), the problem of tropical cyclogenesis in the real

  4. Species Loss and Aboveground Carbon Storage in a Tropical Forest

    E-Print Network [OSTI]

    Bunker, Daniel E.

    of tropical tree species on carbon storage by simulating 18 possible extinction scenarios within a well-studied 50-hectare tropical forest plot in Panama, which contains 227 tree species. Among extinction as well as the size and longevity of tropical trees. Instead, we simulated species extinctions

  5. Investigating Tropical Deforestation Using Two-Stage Spatially Misaligned

    E-Print Network [OSTI]

    Silander Jr., John A.

    Investigating Tropical Deforestation Using Two-Stage Spatially Misaligned Regression Models Deepak Deforestation in the tropics has been a major concern in conservationscience for more than 20 years. Estimates of tropical deforestation over the past few decades have shown an alarming accelerationin forest lost. Concern

  6. ONGOING RESEARCH PROJECTS Model of tropical forest structure and dynamics

    E-Print Network [OSTI]

    Hill, Jeffrey E.

    ONGOING RESEARCH PROJECTS Model of tropical forest structure and dynamics There is a need canopy structure and partitions dynamic rates for a tropical forest on Barro Colorado Island (BCI structure and partitions dynamic rates in a tropical forest. In Review. Journal of Ecology. #12;PPA model

  7. The development of convective instability in relation to convective activity and synoptic systems in AVE IV

    E-Print Network [OSTI]

    Davis, James Gregory

    1979-01-01T23:59:59.000Z

    700 mb 500 mb 300 mb 100 mb 1. 8 2 54 3. 1' 6. 2 3. 8 5 64 7 5 15. 0 RMS Direction Error RNS ~Seed Error -1 -1 0. 5ms l. oms -1 -1 0. 8 m s 2. 0 m s -1 -1 10ms 3. 8ms -1 -1 2. 0 m s 5. 7 m s The rawinsonde data were supplemented by hourly... of Co ttee) 4' (Member) N. I (Member) (Head of Department) August 1979 ABSTRACT Tha Development of Convective Instability in Relation to ConVectiVe Activity and Synoptic Systems in AVE 1V, (August 1979$ James Gregory Davis, B. S. , Texas A&M...

  8. Alien plant invasions in tropical and sub-tropical savannas: patterns, processes and prospects

    E-Print Network [OSTI]

    Foxcroft, Llewellyn C.; Richardson, David M.; RejmŠnek, Marcel; Pyöek, Petr

    2010-01-01T23:59:59.000Z

    Tanzania Species Family Alien plant invasions in savannasLo pez-Olmedo et al. 2007). Alien plant invasions in Africanspecies of naturalised alien plants for tropical savannas in

  9. Divergent subcritical convection in magnetized plasma from asymmetric sourcing

    SciTech Connect (OSTI)

    Adler, D.T.; Hassam, A.B. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2005-06-15T23:59:59.000Z

    Asymmetric particle and heat sourcing in a plasma confined in a closed magnetic field line configuration results in convection cells, as is well known. This phenomenon occurs even if the sourcing on average produces density and temperature profiles that are subcritical, i.e., magnetohydrodynamically stable to interchange modes. Such subcritical convection is expected to be small compared to the convection from supercritical driving for which the system is interchange unstable. The ratio of subcritical to supercritical convection is expected to scale as the inverse Reynolds numbers (for large Reynolds numbers). It is shown that this ratio is, in fact, considerably larger. As marginal stability is approached, the subcritical convection grows from very small to almost the unstable convection size, i.e., of order unity. This effect may be similar to why a driven, damped harmonic oscillator increases in amplitude as resonance is approached. A numerical simulation is done to demonstrate this effect. It is also shown that transport from the large convection can be substantial.

  10. 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.

  11. Climate Science: Tropical Expansion by Ocean Swing

    SciTech Connect (OSTI)

    Lu, Jian

    2014-04-01T23:59:59.000Z

    The tropical belt has become wider over the past decades, but climate models fall short of capturing the full rate of the expansion. The latest analysis of the climate simulations suggests that a long-term swing of the Pacific Decadal Oscillation is the main missing cause.

  12. Numerical and Experimental Modeling of Natural Convection for a Cryogenic Prototype of a Titan

    E-Print Network [OSTI]

    Colonius, Tim

    in Sutherland's law D = diameter g = gravitation acceleration h = convection coefficient k = thermal

  13. Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure Keywords: Supercritical pressure Aviation kerosene Convective heat transfer Numerical study a b s t r a c convective in kerosene pipe flow is complicated. Here the convective heat transfer characteristics of China

  14. PHYSICS OF FLUIDS 25, 044105 (2013) Onset of buoyancy-driven convection in Cartesian

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    the onset of buoyancy-driven convection relevant to subsurface carbon dioxide sequestration in confined

  15. Measuring kinetic energy changes in the mesoscale with low acquisition rates

    SciTech Connect (OSTI)

    RoldŠn, …. [ICFOĖInstitut de CiŤncies FotÚniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); GISCĖGrupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); MartŪnez, I. A.; Rica, R. A., E-mail: rul@ugr.es [ICFOĖInstitut de CiŤncies FotÚniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); Dinis, L. [GISCĖGrupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Departamento de FŪsica Atůmica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain)

    2014-06-09T23:59:59.000Z

    We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.

  16. Impact of mesoscale eddies on water transport between the Pacific Ocean and the Bering Sea

    E-Print Network [OSTI]

    Prants, S V; Budyansky, M V; Uleysky, M Yu

    2013-01-01T23:59:59.000Z

    Sea surface height anomalies observed by satellites in 1993--2012 are combined with simulation and observations by surface drifters and Argo floats to study water flow pattern in the Near Strait (NS) connected the Pacific Ocean with the Bering Sea. Daily Lagrangian latitudinal maps, computed with the AVISO surface velocity field, and calculation of the transport across the strait show that the flow through the NS is highly variable and controlled by mesoscale and submesoscale eddies in the area. On the seasonal scale, the flux through the western part of the NR is negatively correlated with the flux through its eastern part ($r=-0.93$). On the interannual time scale, a significant positive correlation ($r=0.72$) is diagnosed between the NS transport and the wind stress in winter. Increased southward component of the wind stress decreases the northward water transport through the strait. Positive wind stress curl over the strait area in winter--spring generates the cyclonic circulation and thereby enhances the...

  17. The reduction of plankton biomass induced by mesoscale stirring: a modeling study in the Benguela upwelling

    E-Print Network [OSTI]

    Ismael HernŠndez-Carrasco; Vincent Rossi; Emilio HernŠndez-GarcŪa; Veronique GarÁon; Cristůbal Lůpez

    2013-11-05T23:59:59.000Z

    Recent studies, both based on remote sensed data and coupled models, showed a reduction of biological productivity due to vigorous horizontal stirring in upwelling areas. In order to better understand this phenomenon, we consider a system of oceanic flow from the Benguela area coupled with a simple biogeochemical model of Nutrient-Phyto-Zooplankton (NPZ) type. For the flow three different surface velocity fields are considered: one derived from satellite altimetry data, and the other two from a regional numerical model at two different spatial resolutions. We compute horizontal particle dispersion in terms of Lyapunov Exponents, and analyzed their correlations with phytoplankton concentrations. Our modelling approach confirms that in the south Benguela there is a reduction of biological activity when stirring is increased. Two-dimensional offshore advection and latitudinal difference in Primary Production, also mediated by the flow, seem to be the dominant processes involved. We estimate that mesoscale processes are responsible for 30 to 50% of the offshore fluxes of biological tracers. In the northern area, other factors not taken into account in our simulation are influencing the ecosystem. We suggest explanations for these results in the context of studies performed in other eastern boundary upwelling areas.

  18. Simulations of amphiphilic fluids using mesoscale lattice-Boltzmann and lattice-gas methods

    E-Print Network [OSTI]

    P. J. Love; M. Nekovee; J. Chin; N. Gonzalez-Segredo; P. V. Coveney

    2002-12-06T23:59:59.000Z

    We compare two recently developed mesoscale models of binary immiscible and ternary amphiphilic fluids. We describe and compare the algorithms in detail and discuss their stability properties. The simulation results for the cases of self-assembly of ternary droplet phases and binary water-amphiphile sponge phases are compared and discussed. Both models require parallel implementation and deployment on large scale parallel computing resources in order to achieve reasonable simulation times for three-dimensional models. The parallelisation strategies and performance on two distinct parallel architectures are compared and discussed. Large scale three dimensional simulations of multiphase fluids requires the extensive use of high performance visualisation techniques in order to enable the large quantities of complex data to be interpreted. We report on our experiences with two commercial visualisation products: AVS and VTK. We also discuss the application and use of novel computational steering techniques for the more efficient utilisation of high performance computing resources. We close the paper with some suggestions for the future development of both models.

  19. Life Cycle of a Mesoscale Circular Gust Front Observed by a C-Band Doppler Radar in West Africa

    E-Print Network [OSTI]

    Lothon, Marie

    On 10 July 2006, during the Special Observation Period (SOP) of the African Monsoon Multidisciplinary Analysis (AMMA) campaign, a small convective system initiated over Niamey and propagated westward in the vicinity of ...

  20. atmospheric convective boundary: Topics by E-print Network

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

    convective conditions is found to be primarily due to variations in mixed layer wind speed. Low-level winds thus play the major role in regulating the ability of thermals to...

  1. Effects of aerosols on deep convective cumulus clouds

    E-Print Network [OSTI]

    Fan, Jiwen

    2009-05-15T23:59:59.000Z

    This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed...

  2. Experimental Investigation of Natural Convection in Trombe Wall Systems

    E-Print Network [OSTI]

    Chen, B.; Zhao, J.; Chen, C.; Zhuang, Z.

    2006-01-01T23:59:59.000Z

    In this paper, experiments with a passive solar building with Trombe wall in the north cold climate are carried out and discussed, and the natural convection heat transfer process has been investigated. The relativity of the factors affecting indoor...

  3. Rotation of the solar convection zone from helioseismology

    E-Print Network [OSTI]

    J. Christensen-Dalsgaard

    2006-10-31T23:59:59.000Z

    Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to the nearly uniformly rotating radiative interior takes place in a narrow tachocline, which is likely important to the operation of the solar magnetic cycle.The convection-zone rotation displays zonal flows, regions of slightly more rapid and slow rotation, extending over much of the depth of the convection zone and converging towards the equator as the solar cycle progresses. In addition, there is some evidence for a quasi-periodic variation in rotation, with a period of around 1.3 yr, at the equator near the bottom of the convection zone.

  4. Survey and evaluation of techniques to augment convective heat transfer

    E-Print Network [OSTI]

    Bergles A. E.

    1965-01-01T23:59:59.000Z

    This report presents a survey and evaluation of the numerous techniques which have been shown to augment convective heat transfer. These techniques are: surface promoters, including roughness and treatment; displaced ...

  5. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    E-Print Network [OSTI]

    Gadgil, Ashok; Bauman, Fred; Kammerud, Ronald

    2008-01-01T23:59:59.000Z

    effect of the adjacent conditioned zones was properly accounted for by the BLASTeffects of this observation on the accuracy of results from the programs, the convection code was used iteratively with BLAST

  6. VARIATION OF STELLAR ENVELOPE CONVECTION AND OVERSHOOT WITH METALLICITY

    SciTech Connect (OSTI)

    Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)] [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2013-04-10T23:59:59.000Z

    We examine how metallicity affects convection and overshoot in the superadiabatic layer of main sequence stars. We present results from a grid of three-dimensional radiation hydrodynamic simulations with four metallicities (Z = 0.040, 0.020, 0.010, 0.001), and spanning a range in effective temperature (4950 < T{sub eff} < 6230). We show that changing the metallicity alters properties of the convective gas dynamics, and the structure of the superadiabatic layer and atmosphere. Our grid of simulations shows that the amount of superadiabaticity, which tracks the transition from efficient to inefficient convection, is sensitive to changes in metallicity. We find that increasing the metallicity forces the location of the transition region to lower densities and pressures, and results in larger mean and turbulent velocities throughout the superadiabatic region. We also quantify the degree of convective overshoot in the atmosphere, and show that it increases with metallicity as well.

  7. Land-atmosphere interaction and radiative-convective equilibrium

    E-Print Network [OSTI]

    Cronin, Timothy (Timothy Wallace)

    2014-01-01T23:59:59.000Z

    I present work on several topics related to land-atmosphere interaction and radiative-convective equilibrium: the first two research chapters invoke ideas related to land-atmosphere interaction to better understand ...

  8. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    heat, and thermal conductivity of the ground and grid sizegrid was stretched uniformly to 0.1 m resolution. The heatheat flux) are friction velocity and convective velocity respectively. The grid

  9. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, F.; Kammerud, R.

    1981-04-01T23:59:59.000Z

    Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

  10. Possible solar cycle variations in the convection zone

    E-Print Network [OSTI]

    Sarbani Basu; H. M. Antia

    2000-01-26T23:59:59.000Z

    Using data from the Global Oscillations Network Group (GONG) that covers the period from 1995 to 1998 we study the change in frequencies of solar oscillations with solar activity. From these frequencies we attempt to determine any possible variation in solar structure with solar activity. We do not find any evidence of a change in the convection zone depth or extent of overshoot below the convection zone during the solar cycle.

  11. Natural convection airflow and heat transport in buildings: experimental results

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.

    1985-01-01T23:59:59.000Z

    Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

  12. On the connection between continental-scale land surface processes and the tropical climate in a coupled ocean-atmosphere-land system

    E-Print Network [OSTI]

    Ma, H-Y; Mechoso, CR; Xue, Y; Xiao, H; Neelin, JD; Ji, X

    2013-01-01T23:59:59.000Z

    the remote response to the convective heating in Africa, weand remote regions. The convective heating anomalies

  13. Thermal effects of Kohout convection in the Bahamas and Florida

    SciTech Connect (OSTI)

    Simms, M.A.

    1985-01-01T23:59:59.000Z

    Kohout convection is a low-temperature groundwater thermal convection process in carbonate platform margins. It was first conceived of and postulated to occur in the subsurface of Florida by Francis Kohout in the 1960's. The flow is driven by buoyancy arising from subsurface differences in salinity and in temperature. Cold, dense seawater surrounding a platform at depth migrates inward, displacing warmer pore waters at the same elevation. This inflowing density current is in turn warmed within the platform and is buoyed upward to discharge on the platform shelf or margin resulting in a giant convective half-cell. In isolated platforms, such as the Bahamas, temperature differences alone drive Kohout convection. In Florida, the regional meteoric flow of the Floridan Aquifer mixes by dispersion with the convecting seawater resulting in an enhanced flow rate. Approximate analytical and numerical solutions of the governing differential equations allow the interactions of the flow and temperature fields to be determined. Permeability characteristics and platform margin geometry are the principal controls of the thermal structure and groundwater flow pattern in isolated platforms. In Florida, regional flow strength is also a control. High horizontal permeabilities (100 md to 1 darcy and higher) and tall, steep margins (1 km height, 30/sup 0/ slope) allow Kohout convection to penetrate 30 to 50 km inland causing substantial cooling. It may thus be a control of thermal evolution of the Florida-Bahamas Basin as well as parts of other sedimentary basins.

  14. Natural convection heat transfer within horizontal spent nuclear fuel assemblies

    SciTech Connect (OSTI)

    Canaan, R.E.

    1995-12-01T23:59:59.000Z

    Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.

  15. ADVANCED TROPICAL METEOROLOGY: METR 5453.001 T R 11:30-12:45, NWC 5820

    E-Print Network [OSTI]

    Droegemeier, Kelvin K.

    and their limitations. - Why study the tropics separately? Examples of major tropical circulations on weather. - Easterly waves. 5. Tropical Cyclones What are they? How do they differ from extratropical cyclones cyclones: operations and research. - Predictability aspects of tropical cyclones. - Tropical cyclones

  16. Dynamic Transitions of Surface Tension Driven Convection

    E-Print Network [OSTI]

    Henk Dijkstra; Taylan Sengul; Shouhong Wang

    2011-05-05T23:59:59.000Z

    We study the well-posedness and dynamic transitions of the surface tension driven convection in a three-dimensional (3D) rectangular box with non-deformable upper surface and with free-slip boundary conditions. It is shown that as the Marangoni number crosses the critical threshold, the system always undergoes a dynamic transition. In particular, two different scenarios are studied. In the first scenario, a single mode losing its stability at the critical parameter gives rise to either a Type-I (continuous) or a Type-II (jump) transition. The type of transitions is dictated by the sign of a computable non-dimensional parameter, and the numerical computation of this parameter suggests that a Type-I transition is favorable. The second scenario deals with the case where the geometry of the domain allows two critical modes which possibly characterize a hexagonal pattern. In this case we show that the transition can only be either a Type-II or a Type-III (mixed) transition depending on another computable non-dimensional parameter. We only encountered Type-III transition in our numerical calculations. The second part of the paper deals with the well-posedness and existence of global attractors for the problem.

  17. EVIDENCE FOR CONVECTION IN SUNSPOT PENUMBRAE

    SciTech Connect (OSTI)

    Bharti, L.; Solanki, S. K.; Hirzberger, J., E-mail: bharti@mps.mpg.d [Max-Planck-Institute fuer sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau (Germany)

    2010-10-20T23:59:59.000Z

    We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from 30{sup 0} to 48{sup 0} using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI) on board Hinode. The relations of the twisting motions to the filament brightness and the position within the filament and within the penumbra, respectively, are investigated. Only certain portions of the filaments show twisting motions. In a statistical sense, the part of the twisting portion of a filament located closest to the umbra is brightest and possesses the fastest twisting motion, with a mean twisting velocity of 2.1 km s{sup -1}. The middle and outer sections of the twisting portion of the filament (lying increasingly further from the umbra), which are less bright, have mean velocities of 1.7 km s{sup -1} and 1.35 km s{sup -1}, respectively. The observed reduction of brightness and twisting velocity toward the outer section of the filaments may be due to reducing upflow along the filament's long axis. No significant variation of twisting velocity as a function of viewing angles was found. The obtained correlation of brightness and velocity suggests that overturning convection causes the twisting motions observed in penumbral filament and may be the source of the energy needed to maintain the brightness of the filaments.

  18. Relationships between tropical cyclone intensity and satellite based indicators of inner core convection: 85 GHz ice scattering signature and lightning

    E-Print Network [OSTI]

    Cecil, Daniel Joseph

    1997-01-01T23:59:59.000Z

    . REFERENCES. . . . . VITA. . . 116 119 125 LIST OF FIGURES FIGURE I Typhoon Oscar 85 GHz PCT iield at 2117 UTC 15 September 1995. . . . , Page 2 Correlations between 0-1' radius PCT parameters and hurricane/typhoon intensity at the time of SSM... miniinum PCT and lightning in Hurricane Barbara. . 79 46 Typhoon Oscar best track, 12 IJTC 7 September - 0 UTC 18 September 1995. . 81 47 Oscar 85 GHz PCT field at 2014 UTC 12 September 1995. . . . . . 48 Oscar 85 GHz PCT field at 2112 IJTC 13 September...

  19. Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction

    SciTech Connect (OSTI)

    Rhodes, M; Lundquist, J K

    2011-09-21T23:59:59.000Z

    Ramping events, or rapid changes of wind speed and wind direction over a short period of time, present challenges to power grid operators in regions with significant penetrations of wind energy in the power grid portfolio. Improved predictions of wind power availability require adequate predictions of the timing of ramping events. For the ramping event investigated here, the Weather Research and Forecasting (WRF) model was run at three horizontal resolutions in 'mesoscale' mode: 8100m, 2700m, and 900m. Two Planetary Boundary Layer (PBL) schemes, the Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ) schemes, were run at each resolution as well. Simulations were not 'tuned' with nuanced choices of vertical resolution or tuning parameters so that these simulations may be considered 'out-of-the-box' tests of a numerical weather prediction code. Simulations are compared with sodar observations during a wind ramping event at a 'West Coast North America' wind farm. Despite differences in the boundary-layer schemes, no significant differences were observed in the abilities of the schemes to capture the timing of the ramping event. As collaborators have identified, the boundary conditions of these simulations probably dominate the physics of the simulations. They suggest that future investigations into characterization of ramping events employ ensembles of simulations, and that the ensembles include variations of boundary conditions. Furthermore, the failure of these simulations to capture not only the timing of the ramping event but the shape of the wind profile during the ramping event (regardless of its timing) indicates that the set-up and execution of such simulations for wind power forecasting requires skill and tuning of the simulations for a specific site.

  20. A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone

    E-Print Network [OSTI]

    Francis J. Robinson; Kwing L. Chan

    2000-11-21T23:59:59.000Z

    We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.

  1. Ocean Barrier Layersí Effect on Tropical Cyclone Intensification

    SciTech Connect (OSTI)

    Balaguru, Karthik; Chang, P.; Saravanan, R.; Leung, Lai-Yung R.; Xu, Zhao; Li, M.; Hsieh, J.

    2012-09-04T23:59:59.000Z

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are 'quasi-permanent' features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  2. Clarence Strait Tidal Energy Project, Tenax Energy Tropical Tidal...

    Open Energy Info (EERE)

    Test Centre, Jump to: navigation, search 1 Retrieved from "http:en.openei.orgwindex.php?titleClarenceStraitTidalEnergyProject,TenaxEnergyTropicalTidalTestCentre,&o...

  3. TROPICAL DEFORESTATION MODELLING: A COMPARATIVE ANALYSIS OF DIFFERENT PREDICTIVE APPROACHES.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    TROPICAL DEFORESTATION MODELLING: A COMPARATIVE ANALYSIS OF DIFFERENT PREDICTIVE APPROACHES-time discretisation; Remote Sensing; Neural Networks; Markov Chains; MCE; Dinamica; Risk management; Deforestation

  4. Benefits of Tropical Forest Management Under the New Climate...

    Open Energy Info (EERE)

    Case Study in Cambodia Jump to: navigation, search Name Benefits of Tropical Forest Management Under the New Climate Change Agreement-A Case Study in Cambodia Agency...

  5. australian tropical savannas: Topics by E-print Network

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

    results in warmer and drier climate of tropical savannas increases temperatures and wind speeds and decreases precipitation and relative humidity Jackson, Robert B. 2...

  6. Insights into the historical construction of species-rich Mesoamerican seasonally dry tropical forests: the diversification

    E-Print Network [OSTI]

    Olson, Mark

    Insights into the historical construction of species-rich Mesoamerican seasonally dry tropical, Mesoamerica, niche conservatism, seasonally dry tropical forests. Summary ∑ Mesoamerican arid biomes epitomize the vast species richness of Meso- american seasonally dry tropical forests (SDTFs), and to evaluate

  7. Carbon sequestration potential of tropical pasture compared with afforestation in Panama

    E-Print Network [OSTI]

    Potvin, Catherine

    Carbon sequestration potential of tropical pasture compared with afforestation in Panama S E B) to estimate the carbon sequestration potential of tropical pasture compared with afforestation; and (3 show the potential for considerable carbon sequestration of tropical afforestation and highlight

  8. Efficient small-scale dynamo in solar convection zone

    E-Print Network [OSTI]

    Hotta, H; Yokoyama, T

    2015-01-01T23:59:59.000Z

    We investigate small-scale dynamo action in the solar convection zone through a series of high resolution MHD simulations in a local Cartesian domain with 1$R_\\odot$ (solar radius) of horizontal extent and a radial extent from 0.715 to 0.96$R_\\odot$. The dependence of the solution on resolution and diffusivity is studied. For a grid spacing of less than 350 km, the root mean square magnetic field strength near the base of the convection zone reaches 95% of the equipartition field strength (i.e. magnetic and kinetic energy are comparable). For these solutions the Lorentz force feedback on the convection velocity is found to be significant. The velocity near the base of the convection zone is reduced to 50% of the hydrodynamic one. In spite of a significant decrease of the convection velocity, the reduction in the enthalpy flux is relatively small, since the magnetic field also suppresses the horizontal mixing of the entropy between up- and downflow regions. This effect increases the amplitude of the entropy pe...

  9. Tropical Pacific nutrient dynamics in the modern and pleistocene ocean : insights from the nitrogen isotope system

    E-Print Network [OSTI]

    Rafter, Patrick Anthony

    2009-01-01T23:59:59.000Z

    eastern tropical North Pacific Ocean, Mar. Chem. , 3, 271Ėeastern tropical South Pacific Ocean, Mar. Chem. , 16, 277Ėand N 2 fixation in the Pacific Ocean, Global Biogeochem.

  10. E-Print Network 3.0 - ambiente tropical um Sample Search Results

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

    Summary: and composition of fruit-feeding butterflies in tropical plantation forests. Biodiversity and Conservation. DOI... for biodiversity conservation in the tropics. Tree...

  11. Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material

    SciTech Connect (OSTI)

    Springer, H K

    2008-06-26T23:59:59.000Z

    The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accounted for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed and executed for the purpose of validating closely-coupled 3D MSS. While the spall strength is nearly independent of specimen thickness, the fragment morphology varies widely. Detailed MSS demonstrate that the interactions between the tensile release waves are altered by specimen thickness and that these interactions are primarily responsible for fragment formation. MSS also provided insights on the regional amplification of damage, which enables the development of predictive void evolution models.

  12. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

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

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  13. Isotopic composition of water in the tropical tropopause layer in cloudresolving simulations of an idealized tropical circulation

    E-Print Network [OSTI]

    Romps, David M.

    that both the sublimation of relatively enriched ice associated with deep convection and fractionation role in the climate and chemistry of the stratosphere and also of the Earth as a whole [e.g., Forster convection through the injection and subsequent sublimation of ice [e.g., Corti et al., 2008], dehydration

  14. The iron nutrition of tropical foliage plants

    E-Print Network [OSTI]

    Lang, Harvey Joe

    1986-01-01T23:59:59.000Z

    extraction of Fe from fresh leaves proved to be a good indicator of the Fe status of plants. It consistently gave higher correlations with chlorophyll concentration than other methods tested. Conversely, total Fe analysis on dried leaves did not always... resolve the correct Fe status of the plant. The studies also suggested that P and the ratio of P/0. 1 N HC1-Fe may be important parameters in the diagnosis of Fe status. In a screening of 11 tropical foliage plants, Ficus benj ami ha and Nephroiepi...

  15. ARM - Lesson Plans: Tropical Western Pacific

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAcid RainThe Pacific and El Ni√ĪoTropical

  16. Tropical Cloud Life Cycle and Overlap Structure

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2TopoPortalBRDF Effects inHeterogeneous andTropical

  17. Chapter Number1 Biomass Prediction in Tropical Forests:2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Chapter Number1 Biomass Prediction in Tropical Forests:2 The Canopy Grain Approach3 Christophe France9 1. Introduction10 The challenging task of biomass prediction in dense and heterogeneous tropical different forest structures may indeed present similar above ground biomass (AGB) values.13 This is probably

  18. The Maslov dequantization, idempotent and tropical mathematics: A brief introduction

    E-Print Network [OSTI]

    G. L. Litvinov

    2005-07-01T23:59:59.000Z

    This paper is a brief introduction to idempotent and tropical mathematics. Tropical mathematics can be treated as a result of the so-called Maslov dequantization of the traditional mathematics over numerical fields as the Planck constant $\\hbar$ tends to zero taking imaginary values.

  19. Proximate Population Factors and Deforestation in Tropical Agricultural Frontiers

    E-Print Network [OSTI]

    Lopez-Carr, David

    Proximate Population Factors and Deforestation in Tropical Agricultural Frontiers David L. Carr are significantly associated at the global and regional scales, evidence for population links to deforestation of thought on population­environment theories relevant to deforestation in tropical agricultural frontiers

  20. Carbon accumulation of tropical peatlands over millennia: a modeling approach

    E-Print Network [OSTI]

    in the global carbon cycle by storing about 40≠90 Gt C in peat. Over the past several decades, tropical with lowering the water table and peat burning, releasing large amounts of carbon stored in peat the Holocene Peat Model (HPM), which has been successfully applied to northern temperate peatlands. Tropical

  1. Climate change and tropical biodiversity: a new focus

    E-Print Network [OSTI]

    Wisenden, Brian D.

    Climate change and tropical biodiversity: a new focus Jedediah Brodie1 , Eric Post2 and William F, Australia Considerable efforts are focused on the consequences of climate change for tropical rainforests climatic changes and human land use) remain understudied. Key concerns are that aridification could

  2. TROPICAL CYCLONE RESEARCH REPORT TCRR 2: 131 (2013)

    E-Print Network [OSTI]

    Smith, Roger K.

    circulation (e.g., Marks and Shay 1998). There have been considerable advances in computer technology overTROPICAL CYCLONE RESEARCH REPORT TCRR 2: 1­31 (2013) Meteorological Institute Ludwig Maximilians University of Munich Paradigms for tropical cyclone intensification Michael T. Montgomerya 1 and Roger K

  3. Cyclone Center Using Crowdsourcing to Determine Tropical Cyclone Intensity

    E-Print Network [OSTI]

    Hennon, Christopher C.

    Cyclone Center Using Crowdsourcing to Determine Tropical Cyclone Intensity Almost all tropical cyclones are not directly observed. Agency estimates of storm position and intensity are not homogeneous in time and space. Cyclone Center uses crowdsourcing to collect data that will lead to a consistent

  4. Hybrid coupled modeling of the tropical Pacific using neural networks

    E-Print Network [OSTI]

    Hsieh, William

    Hybrid coupled modeling of the tropical Pacific using neural networks Shuyong Li, William W. Hsieh To investigate the potential for improving hybrid coupled models (HCM) of the tropical Pacific by the use: dynamical coupled models, statistical models and hybrid coupled models [Barnston et al., 1994]. A hybrid

  5. 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

    2010-04-01T23:59:59.000Z

    Convective processes play a critical role in the Earthís energy balance through the redistribution of heat and moisture in the atmosphere and subsequent impacts on the hydrologic cycle. Global observation and accurate representation of these processes in numerical models is vital to improving our current understanding and future simulations of Earthís climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales that are associated with convective and stratiform precipitation processes; therefore, they must turn to parameterization schemes to represent these processes. In turn, the physical basis for these parameterization schemes needs to be evaluated for general application under a variety of atmospheric conditions. Analogously, space-based remote sensing algorithms designed to retrieve related cloud and precipitation information for use in hydrological, climate, and numerical weather prediction applications often rely on physical ďparameterizationsĒ that reliably translate indirectly related instrument measurements to the physical quantity of interest (e.g., precipitation rate). Importantly, both spaceborne retrieval algorithms and model convective parameterization schemes traditionally rely on field campaign data sets as a basis for evaluating and improving the physics of their respective approaches. The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the AprilĖMay 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 Administrationís (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. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

  6. Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01T23:59:59.000Z

    A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...

  7. Severe convection and lightning in subtropical South America By Kristen L. Rasmussen1

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    1 Severe convection and lightning in subtropical South America of the seasonal, diurnal, and extreme storm-related lightning in South America. · Preference for hail radar and radiometer data show that subtropical South America has the world's deepest convective

  8. REVIEWS OF GEOPHYSICS: U.S. NATIONAL REPORT TO INTERNATIONAL UNION OF GEODESY AND GEOPHYSICS COOL SEASON CYCLOGENESIS AND ASSOCIATED MESOSCALE WEATHER

    E-Print Network [OSTI]

    Businger, Steven

    technological advances in our ability to forecast cyclogenesis, one cannot say that the cyclone problem to probe the mesoscale structure and evolution of winter cyclones in recent years. Many recent advances treatment of their dynamics. Kraus and Businger (1994) review the air-sea interaction in cyclones, and Houze

  9. Submitted to Geophysical and Astrophysical Fluid Dynamics Shear and Mixing in Oscillatory Doubly Di usive Convection

    E-Print Network [OSTI]

    Paparella, Francesco

    convection are found in the Earth's oceans, most notably, below the polar ice caps. There melting ice

  10. weber, evans, moser, and newell Air Traffic Management Decision Support During Convective Weather

    E-Print Network [OSTI]

    Reuter, Martin

    · weber, evans, moser, and newell Air Traffic Management Decision Support During Convective WeatherTraffic Management Decision Support During Convective Weather Mark E. Weber, James E. Evans, William R. Moser algorithm. #12;· weber, evans, moser, and newell Air Traffic Management Decision Support During Convective

  11. The ionospheric signature of transient dayside reconnection and the associated pulsed convection return ow

    E-Print Network [OSTI]

    Boyer, Edmond

    of convection. Key words. Ionosphere (plasma convection) √° Magne- tospheric physics (magnetopause, cusp, 1996, and references therein) and the excitation of dayside convection is the focus of the present of magnetosheath plasma into the magneto- sphere, and the ionospheric plasma ¬Įow at the footprint of the cusp

  12. Evolution du contenu physique 1. Nouveau bloc couche limite convection nuages (nouvelle physique)

    E-Print Network [OSTI]

    Madeleine, Jean-Baptiste

    Evolution du contenu physique 1. Nouveau bloc couche limite ­ convection ­ nuages (nouvelle physique) ON DISPOSE D'UN NOUVEAU CADRE DE TRAVAIL. ?? - Convection /relief (Jean-Yves Grandpeix, Jingmei Yu, Alain Lahelec) ++ - glace dans la convection (Arnaud Jam, Jean-Yves Grandpeix) ?? - Modèle micro-physique

  13. A numerical study of convection with an ambient wind field

    E-Print Network [OSTI]

    Cottrell, Kit Garfield

    1970-01-01T23:59:59.000Z

    . The citations on the following pages follow the style of the Journal of the Atmos heric Sciences. Orville (1968) constructed a convective model based on the same equations as those used by Assi. He concerned himself with the development of cumulus clouds over...

  14. EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING

    E-Print Network [OSTI]

    Eagar, Thomas W.

    EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING M.L. Lin, T.W. Eagar Materials of the weld pool which are changed by these fact ors . It is shown that, at current s in excess of 300 amperes in a different heat distribution on the weld pool surface . ALTHOUGH THE GAS tungsten arc (GTA) welding process

  15. Modeling thermal convection in supradetachment basins: example from western Norway

    E-Print Network [OSTI]

    Andersen, Torgeir Bj√łrge

    Modeling thermal convection in supradetachment basins: example from western Norway A. SOUCHE*, M. DABROWSKI AND T. B. ANDERSEN Physics of Geological Processes (PGP), University of Oslo, Oslo, Norway basins of western Norway are examples of supradetachment basins that formed in the hanging wall

  16. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, B.A.; Siminovitch, M.

    1997-07-29T23:59:59.000Z

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

  17. Sparse grid collocation schemes for stochastic natural convection problems

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    stochastic methods and Monte-Carlo based sam- pling methods are two approaches that have been used to analyzeSparse grid collocation schemes for stochastic natural convection problems Baskar on the Smolyak algorithm offers a viable alternate method for solving high-dimensional stochastic partial

  18. Does convective aggregation need to be represented in cumulus parameterizations?

    E-Print Network [OSTI]

    Does convective aggregation need to be represented in cumulus parameterizations? Isabelle Tobin,1 in phenomena such as ``hot spots'' or the Madden-Julian Oscillation. These findings support the need climate models lack any such representation. The ability of a cloud system- resolving model to reproduce

  19. Drift Natural Convection and Seepage at the Yucca Mountain Repository

    E-Print Network [OSTI]

    Halecky, Nicholaus Eugene

    2010-01-01T23:59:59.000Z

    that the heat and mass transfer of the open in-drift can beheat transfer processes[26, 33], in both the fractured rock and the openheat transfer coefficient, hc eff , as described in Appendix A.2.1. For our case, modeling convection in open

  20. NATURAL CONVECTION OF SUBCOOLED LIQUID NITROGEN IN A VERTICAL CAVITY

    E-Print Network [OSTI]

    Chang, Ho-Myung

    temperature superconductor) power devices, such as HTS transformers, fault current limiters, and terminals power transformer cooled by natural convection of subcooled liquid nitrogen. A liquid nitrogen bath of subcooled liquid nitrogen system for an HTS transformer, operating at around 65 K. This system consists

  1. Feedback on vertical velocity. Rotation, convection, self-sustaining process.

    E-Print Network [OSTI]

    Lebovitz, Norman

    Feedback on vertical velocity. Rotation, convection, self-sustaining process. Fabian Waleffe the mechanisms involved in the nonlinear feedback from u to v, yielding a self-sustaining process for shear flows feedback from the streak instability into the rolls sufficient to lead to a self-sustaining process

  2. Numerical analysis of binary fluid convection in extended systems

    E-Print Network [OSTI]

    Batiste, Oriol

    arising in the primary subcritical bifurcation. The dynamics triggered by Eckhaus instability is discussed mixtures. For such mixtures, the onset of convection is via a subcritical Hopf bifurcation that gives rise of S. In the case of the experiment reported in [2] a S = -0.257 water-ethanol mixture is used. A final

  3. Predicting flow reversals in chaotic natural convection using data assimilation

    E-Print Network [OSTI]

    Danforth, Chris

    . The thermosyphon, a type of natural convection loop or non-mechanical heat pump, can be likened to a toy model of climate. Thermosyphons are used in solar water heaters (Belessiotis and Mathiou- lakis, 2002), cooling) and other industrial applications. In these heat pumps, buoyant forces move fluid through a closed loop

  4. OSCILLATORY FLOW FORCED CONVECTION IN MICRO HEAT SPREADERS

    E-Print Network [OSTI]

    Beskok, Ali

    transfer devices, micro heat pipes, based on capillary pumping of a multiphase Įuid in microchannels, have-phase forced convection heat transfer and Įow characteristics of water in microchannels, both in the laminar) concept for ef cient transport of large, concentrated heat loads is introduced. The MHS is a single

  5. Design and fabrication of a meso-scale stirling engine and combustor.

    SciTech Connect (OSTI)

    Echekki, Tarek (Sandia National Laboratories, Livermore, CA); Haroldsen, Brent L. (Sandia National Laboratories, Livermore, CA); Krafcik, Karen L. (Sandia National Laboratories, Livermore, CA); Morales, Alfredo Martin (Sandia National Laboratories, Livermore, CA); Mills, Bernice E. (Sandia National Laboratories, Livermore, CA); Liu, Shiling (Sandia National Laboratories, Livermore, CA); Lee, Jeremiah C. (Sandia National Laboratories, Livermore, CA); Karpetis, Adionos N. (Sandia National Laboratories, Livermore, CA); Chen, Jacqueline H. (Sandia National Laboratories, Livermore, CA); Ceremuga, Joseph T. (Sandia National Laboratories, Livermore, CA); Raber, Thomas N. (Sandia National Laboratories, Livermore, CA); Hekmuuaty, Michelle A. (Sandia National Laboratories, Livermore, CA)

    2005-05-01T23:59:59.000Z

    Power sources capable of supplying tens of watts are needed for a wide variety of applications including portable electronics, sensors, micro aerial vehicles, and mini-robotics systems. The utility of these devices is often limited by the energy and power density capabilities of batteries. A small combustion engine using liquid hydrocarbon fuel could potentially increase both power and energy density by an order of magnitude or more. This report describes initial development work on a meso-scale external combustion engine based on the Stirling cycle. Although other engine designs perform better at macro-scales, we believe the Stirling engine cycle is better suited to small-scale applications. The ideal Stirling cycle requires efficient heat transfer. Consequently, unlike other thermodynamic cycles, the high heat transfer rates that are inherent with miniature devices are an advantage for the Stirling cycle. Furthermore, since the Stirling engine uses external combustion, the combustor and engine can be scaled and optimized semi-independently. Continuous combustion minimizes issues with flame initiation and propagation. It also allows consideration of a variety of techniques to promote combustion that would be difficult in a miniature internal combustion engine. The project included design and fabrication of both the engine and the combustor. Two engine designs were developed. The first used a cylindrical piston design fabricated with conventional machining processes. The second design, based on the Wankel rotor geometry, was fabricated by through-mold electroforming of nickel in SU8 and LIGA micromolds. These technologies provided the requisite precision and tight tolerances needed for efficient micro-engine operation. Electroformed nickel is ideal for micro-engine applications because of its high strength and ductility. A rotary geometry was chosen because its planar geometry was more compatible with the fabrication process. SU8 lithography provided rapid prototypes to verify the design. A final high precision engine was created via LIGA. The micro-combustor was based on an excess enthalpy concept. Development of a micro-combustor included both modeling and experiments. We developed a suite of simulation tools both in support of the design of the prototype combustors, and to investigate more fundamental aspects of combustion at small scales. Issues of heat management and integration with the micro-scale Stirling engine were pursued using CFD simulations. We found that by choice of the operating conditions and channel dimensions energy conversion occurs by catalysis-dominated or catalysis-then-homogeneous phase combustion. The purpose of the experimental effort in micro-combustion was to study the feasibility and explore the design parameters of excess enthalpy combustors. The efforts were guided by the necessity for a practical device that could be implemented in a miniature power generator, or as a stand-alone device used for heat generation. Several devices were fabricated and successfully tested using methane as the fuel.

  6. On the Wavelength of the Rossby Waves Radiated by Tropical Cyclones KYLE D. KROUSE

    E-Print Network [OSTI]

    Sobel, Adam

    of tropical cyclones; the theory then predicts the zonal separation distance of such tropical cyclone pairsOn the Wavelength of the Rossby Waves Radiated by Tropical Cyclones KYLE D. KROUSE Department cyclone (TC). In some cases, such disturbances undergo tropical cyclogenesis, resulting in a pair

  7. Transport of Magnetic Fields in Convective, Accreting Supernova Cores

    E-Print Network [OSTI]

    Christopher Thompson; Norman Murray

    2001-05-24T23:59:59.000Z

    We consider the amplification and transport of a magnetic field in the collapsed core of a massive star, including both the region between the neutrinosphere and the shock, and the central, opaque core. An analytical argument explains why rapid convective overturns persist within a newly formed neutron star for roughly 10 seconds ($> 10^3$ overturns), consistent with recent numerical models. A dynamical balance between turbulent and magnetic stresses within this convective layer corresponds to flux densities in excess of $10^{15}$G. Material accreting onto the core is heated by neutrinos and also becomes strongly convective. We compare the expected magnetic stresses in this convective `gain layer' with those deep inside the neutron core. Buoyant motions of magnetized fluid are greatly aided by the intense neutrino flux. We calculate the transport rate through a medium containing free neutrons protons, and electrons, in the limiting cases of degenerate or non-degenerate nucleons. Fields stronger than $\\sim 10^{13}$ G are able to rise through the outer degenerate layers of the neutron core during the last stages of Kelvin-Helmholtz cooling (up to 10 seconds post-collapse), even though these layers have become stable to convection. We also find the equilibrium shape of a thin magnetic flux rope in the dense hydrostatic atmosphere of the neutron star, along with the critical separation of the footpoints above which the rope undergoes unlimited expansion against gravity. The implications of these results for pulsar magnetism are summarized, and applied to the case of late fallback over the first 1,000-10,000 s of the life of a neutron star

  8. Carbonaceous spheresóan unusual template for solid metal oxide mesoscale spheres: Application to ZnO spheres

    SciTech Connect (OSTI)

    Patrinoiu, Greta; Calderůn-Moreno, Jose Maria; Culita, Daniela C. [Illie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Birjega, Ruxandra [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box Mgó27, Magurele, Bucharest (Romania); Ene, Ramona [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Carp, Oana, E-mail: ocarp@icf.ro [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania)

    2013-06-15T23:59:59.000Z

    A green template route for the synthesis of mesoscale solid ZnO spheres was ascertained. The protocol involves a double coating of the carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. The composites were characterized by FTIR spectroscopy, thermal analysis, scanning electron microscopy while the obtained ZnO spheres by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, N{sub 2} adsorptionĖdesorption isotherms and photoluminescence investigations. A growth mechanism of the solid spheres is advanced based on these results. While the spheres' diameters and the mean size values of ZnO are independent on deposition order, the surface area and the external porosity are fairly dependent. The photoluminescence measurements showed interesting emission features, with emission bands in the violet to orange region. The spheres present high photocatalytical activity towards the degradation of phenol under UV irradiation, the main reaction being its mineralization. - Graphical abstract: A novel and eco-friendly methodology for the synthesis of mesoscale solid ZnO spheres was developed. The protocol involves a double coating of the starch-derived carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. - Highlights: ē ZnO solid spheres are obtained via a template route using carbonaceous spheres. ē Two-step coatings of interchangeable order are used as deposition procedure. ē The coating procedure influences the porosity and surface area. ē ZnO spheres exhibited interesting visible photoluminescence properties. ē Solid spheres showed photocatalytical activity in degradation of phenol.

  9. Inter-annual Tropospheric Aerosol Variability in Late Twentieth Century and its Impact on Tropical Atlantic and West African Climate by Direct and Semi-direct Effects

    SciTech Connect (OSTI)

    Evans, Katherine J [ORNL; Hack, James J [ORNL; Truesdale, John [National Center for Atmospheric Research (NCAR); Mahajan, Salil [ORNL; Lamarque, J-F [University Center for Atmospheric Research

    2012-01-01T23:59:59.000Z

    A new high-resolution (0.9$^{\\circ}$x1.25$^{\\circ}$ in the horizontal) global tropospheric aerosol dataset with monthly resolution is generated using the finite-volume configuration of Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the latter part of twentieth century. The surface emissions dataset is constructed from Coupled Model Inter-comparison Project (CMIP5) decadal-resolution surface emissions dataset to include REanalysis of TROpospheric chemical composition (RETRO) wildfire monthly emissions dataset. Experiments forced with the new tropospheric aerosol dataset and conducted using the spectral configuration of CAM4 with a T85 truncation (1.4$^{\\circ}$x1.4$^{\\circ}$) with prescribed twentieth century observed sea surface temperature, sea-ice and greenhouse gases reveal that variations in tropospheric aerosol levels can induce significant regional climate variability on the inter-annual timescales. Regression analyses over tropical Atlantic and Africa reveal that increasing dust aerosols can cool the North African landmass and shift convection southwards from West Africa into the Gulf of Guinea in the spring season in the simulations. Further, we find that increasing carbonaceous aerosols emanating from the southwestern African savannas can cool the region significantly and increase the marine stratocumulus cloud cover over the southeast tropical Atlantic ocean by aerosol-induced diabatic heating of the free troposphere above the low clouds. Experiments conducted with CAM4 coupled to a slab ocean model suggest that present day aerosols can shift the ITCZ southwards over the tropical Atlantic and can reduce the ocean mixed layer temperature beneath the increased marine stratocumulus clouds in the southeastern tropical Atlantic.

  10. The Role of Moist Processes in the Intrinsic Predictability of Indian Ocean Cyclones

    SciTech Connect (OSTI)

    Taraphdar, Sourav; Mukhopadhyay, P.; Leung, Lai-Yung R.; Zhang, Fuqing; Abhilash, S.; Goswami, B. N.

    2014-07-16T23:59:59.000Z

    The role of moist processes and the possibility of error cascade from cloud scale processes affecting the intrinsic predictable time scale of a high resolution convection permitting model within the environment of tropical cyclones (TCs) over the Indian region are investigated. Consistent with past studies of extra-tropical cyclones, it is demonstrated that moist processes play a major role in forecast error growth which may ultimately limit the intrinsic predictability of the TCs. Small errors in the initial conditions may grow rapidly and cascades from smaller scales to the larger scales through strong diabatic heating and nonlinearities associated with moist convection. Results from a suite of twin perturbation experiments for four tropical cyclones suggest that the error growth is significantly higher in cloud permitting simulation at 3.3 km resolutions compared to simulations at 3.3 km and 10 km resolution with parameterized convection. Convective parameterizations with prescribed convective time scales typically longer than the model time step allows the effects of microphysical tendencies to average out so convection responds to a smoother dynamical forcing. Without convective parameterizations, the finer-scale instabilities resolved at 3.3 km resolution and stronger vertical motion that results from the cloud microphysical parameterizations removing super-saturation at each model time step can ultimately feed the error growth in convection permitting simulations. This implies that careful considerations and/or improvements in cloud parameterizations are needed if numerical predictions are to be improved through increased model resolution. Rapid upscale error growth from convective scales may ultimately limit the intrinsic mesoscale predictability of the TCs, which further supports the needs for probabilistic forecasts of these events, even at the mesoscales.

  11. A Comparison of Precipitation Forecast Skill between Small Convection-Allowing and Large Convection-Parameterizing Ensembles

    E-Print Network [OSTI]

    Droegemeier, Kelvin K.

    A Comparison of Precipitation Forecast Skill between Small Convection- Allowing and Large Submitted to Weather and Forecasting in October 2008, Accepted in January 2009 * Corresponding author precipitation forecasts from a 5-member, 4-km grid-spacing (ENS4) and a 15-member, 20-km grid-spacing (ENS20

  12. 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.

  13. 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.

  14. Southern Hemisphere Additional Ozonesondes (SHADOZ) 19982000 tropical ozone climatology

    E-Print Network [OSTI]

    Thompson, Anne

    ozone record from Paramaribo, Surinam (6¬įN, 55¬įW) (also in SHADOZ) shows a marked contrast to southern tropical ozone because Surinam is often north of the Intertropical Convergence Zone (ITCZ). A more

  15. The Political Economy of Deforestation in the Tropics

    E-Print Network [OSTI]

    Burgess, Robin

    Tropical deforestation accounts for almost one-fifth of greenhouse gas emissions and threatens the worldís most diverse ecosystems. Much of this deforestation is driven by illegal logging. We use novel satellite data that ...

  16. Commercial Building HVAC Energy Usage in Semi-Tropical Climates

    E-Print Network [OSTI]

    Worbs, H. E.

    1987-01-01T23:59:59.000Z

    The design of heating and cooling equipment in semi-tropical climates presents some design considerations and limitations not so prevalent in temperate climates. In some cases, the heating season may be non-existent for all practical purposes...

  17. american tropical cyclone: Topics by E-print Network

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

    24 25 Next Page Last Page Topic Index 21 Cross-equatorial influences of a South American cold surge on the development of two eastern North Pacific tropical cyclones Texas A&M...

  18. Eddy formation and propagation in the eastern tropical Pacific

    E-Print Network [OSTI]

    Jhingran, Vikas Gopal

    1997-01-01T23:59:59.000Z

    Observations of eddies in the eastern tropical Pacific from TOPEX altimetry data show that there are seasonal and interannual variations in eddy activity. Comparisons between time of eddy formation and corresponding wind data show that not all...

  19. african tropical forests: Topics by E-print Network

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

    Cory C. Cleveland1,4, and Alan R in tropical rain forests may be among the highest on earth. However, data supporting this contention are rare Cleveland, Cory 116 THE WEST...

  20. african tropical forest: Topics by E-print Network

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

    Cory C. Cleveland1,4, and Alan R in tropical rain forests may be among the highest on earth. However, data supporting this contention are rare Cleveland, Cory 116 THE WEST...

  1. Reduction of tropical land region precipitation variability via transpiration

    E-Print Network [OSTI]

    Lee, Jung-Eun

    Tropical rainforests are known to exhibit low intraseasonal precipitation variability compared with oceanic areas with similar mean precipitation in observations and models. In the present study, the potential role of ...

  2. annual tropical cyclone: Topics by E-print Network

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

    SEASONAL AND MONTHLY FORECASTS Geosciences Websites Summary: 10 12.25 8 5.75 Accumulated Cyclone Energy (ACE) (96.2) 130 170 170 150 148 100 68 Net Tropical't press us too hard on...

  3. Surface Fluxes and Tropical Intraseasonal Variability: a Reassessment

    E-Print Network [OSTI]

    Ribes, Aurťlien

    and Department of Earth and Environmental Sciences, Columbia University, New York, New York, USA 2 Department whose essential features -- its existence, energetics, spatial and temporal scales -- remain so be fundamental similarities in their energetics. General circulation models (GCMs) simulate tropical

  4. WMO/CAS/WWW SIXTH INTERNATIONAL WORKSHOP on TROPICAL CYCLONES

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    to Human and Economic Losses Rapporteur: Roger A. Pielke, Jr. Center for Science and Technology Policy.2.3 Tropical cyclone case studies a) India b) Australia c) United States 5.2.4 Differing views of the role

  5. Diamagnetic pumping near the base of a stellar convection zone

    E-Print Network [OSTI]

    L. L. Kitchatinov; G. RŁdiger

    2008-02-18T23:59:59.000Z

    The property of inhomogeneous turbulence in conducting fluids to expel large-scale magnetic fields in the direction of decreasing turbulence intensity is shown as important for the magnetic field dynamics near the base of a stellar convection zone. The downward diamagnetic pumping confines a fossil internal magnetic field in the radiative core so that the field geometry is appropriate for formation of the solar tachocline. For the stars of solar age, the diamagnetic confinement is efficient only if the ratio of turbulent magnetic diffusivity of the convection zone to the (microscopic or turbulent) diffusivity of the radiative interiour is larger than 10^5. Confinement in younger stars require still larger diffusivity ratio. The observation of persistent magnetic structures on young solar-type stars can thus provide evidences for the nonexistence of tachoclines in stellar interiors and on the level of turbulence in radiative cores.

  6. Dissipation Efficiency in Turbulent Convective Zones in Low Mass Stars

    E-Print Network [OSTI]

    Kaloyan Penev; Dimitar Sasselov; Frank Robinson; Pierre Demarque

    2009-09-26T23:59:59.000Z

    We extend the analysis of Penev et al. (2007) to calculate effective viscosities for the surface convective zones of three main sequence stars of 0.775Msun, 0.85Msun and the present day Sun. In addition we also pay careful attention to all normalization factors and assumptions in order to derive actual numerical prescriptions for the effective viscosity as a function of the period and direction of the external shear. Our results are applicable for periods that are too long to correspond to eddies that fall within the inertial subrange of Kolmogorov scaling, but no larger than the convective turnover time, when the assumptions of the calculation break down. We find linear scaling of effective viscosity with period and magnitudes at least three times larger than the Zahn (1966, 1989) prescription.

  7. The Critical Rayleigh Number in Horizontal Convection for $\\Pran=1$

    E-Print Network [OSTI]

    Sun, L; Sun, De-Jun; Sun, Liang

    2007-01-01T23:59:59.000Z

    We report the numerical simulations of the horizontal convection within a rectangle cavity tank at high Rayleigh numbers. The physical solution of horizontal convection depends the space resolution of the meshes. The mesh number $N$ is proportion to $Ra^{1/3}$. The unstable numerical solutions are obtained as $Npower law also implies that the space resolution is dominated by the viscosity and heat diffusion. It implies that the special resolution is dominated by viscosity and thermal diffusivity but the length of the tank. Moreover, there is a Hopf bifurcation from steady solutions to unsteady solutions and the critical Rayleigh number $Ra_c$ is obtained as $5.53\\times 10^8

  8. 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 AprilĖMay 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 Administrationís (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.

  9. COMPARING THE EFFECT OF RADIATIVE TRANSFER SCHEMES ON CONVECTION SIMULATIONS

    SciTech Connect (OSTI)

    Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2012-11-10T23:59:59.000Z

    We examine the effect of different radiative transfer schemes on the properties of three-dimensional (3D) simulations of near-surface stellar convection in the superadiabatic layer, where energy transport transitions from fully convective to fully radiative. We employ two radiative transfer schemes that fundamentally differ in the way they cover the 3D domain. The first solver approximates domain coverage with moments, while the second solver samples the 3D domain with ray integrations. By comparing simulations that differ only in their respective radiative transfer methods, we are able to isolate the effect that radiative efficiency has on the structure of the superadiabatic layer. We find the simulations to be in good general agreement, but they show distinct differences in the thermal structure in the superadiabatic layer and atmosphere.

  10. Influence of geometry on natural convection in buildings

    SciTech Connect (OSTI)

    White, M.D.; Winn, C.B.; Jones, G.F.; Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Strong free convection airflows occur within passive solar buildings resulting from elevated temperatures of surfaces irradiated by solar energy compared with the cooler surfaces not receiving radiation. The geometry of a building has a large influence on the directions and magnitudes of natural airflows, and thus heat transfer between zones. This investigation has utilized a variety of reduced-scale building configurations to study the effects of geometry on natural convection heat transfer. Similarity between the reduced-scale model and a full-scale passive solar building is achieved by having similar geometries and by replacing air with Freon-12 gas as the model's working fluid. Filling the model with Freon-12 gas results in similarity in Prandtl numbers and Rayleigh numbers based on temperature differences in the range from 10/sup 9/ to 10/sup 11/. Results from four geometries are described with an emphasis placed on the effects of heat loss on zone temperature stratification shifts.

  11. The Tropical Brown Alga Lobophora variegata (Lamouroux) Womersley: A Prospective Bioindicator for Ag Contamination in Tropical Coastal Waters

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    The Tropical Brown Alga Lobophora variegata (Lamouroux) Womersley: A Prospective Bioindicator determined in the brown alga Lobophora variegata, using radiotracer techniques. Results indicate that this widely distributed alga could be a useful bioindicator species for surveying silver contamination

  12. Response of tropical sea surface temperature, precipitation, and tropical cyclone-related variables to changes in global and local forcing

    E-Print Network [OSTI]

    Sobel, Adam

    A single-column model is used to estimate the equilibrium response of sea surface temperature (SST), precipitation, and several variables related to tropical cyclone (TC) activity to changes in both local and global forcing. ...

  13. THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Murphy, Jeremiah W.; Dolence, Joshua C.; Burrows, Adam, E-mail: jmurphy@astro.princeton.edu, E-mail: jdolence@astro.princeton.edu, E-mail: burrows@astro.princeton.edu [Princeton University, Princeton, NJ (United States)

    2013-07-01T23:59:59.000Z

    Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the driving mechanism of the dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven simulations and propose scaling relations for neutrino-driven convection. Through these comparisons, we infer that buoyancy-driven convection dominates post-shock turbulence in our simulations. In support of this inference, we present four major results. First, the convective fluxes and kinetic energies in the neutrino-heated region are consistent with expectations of buoyancy-driven convection. Second, the convective flux is positive where buoyancy actively drives convection, and the radial and tangential components of the kinetic energy are in rough equipartition (i.e., K{sub r} {approx} K{sub {theta}} + K{sub {phi}}). Both results are natural consequences of buoyancy-driven convection, and are commonly observed in simulations of convection. Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective luminosity and turbulent dissipation scale with the driving neutrino power. In all, these four results suggest that in neutrino-driven explosions, the multi-dimensional motions are consistent with neutrino-driven convection.

  14. AERIAL MEASUREMENTS OF CONVECTION CELL ELEMENTS IN HEATED LAKES

    SciTech Connect (OSTI)

    Villa-Aleman, E; Saleem Salaymeh, S; Timothy Brown, T; Alfred Garrett, A; Malcolm Pendergast, M; Linda Nichols, L

    2007-12-19T23:59:59.000Z

    Power plant-heated lakes are characterized by a temperature gradient in the thermal plume originating at the discharge of the power plant and terminating at the water intake. The maximum water temperature discharged by the power plant into the lake depends on the power generated at the facility and environmental regulations on the temperature of the lake. Besides the observed thermal plume, cloud-like thermal cells (convection cell elements) are also observed on the water surface. The size, shape and temperature of the convection cell elements depends on several parameters such as the lake water temperature, wind speed, surfactants and the depth of the thermocline. The Savannah River National Laboratory (SRNL) and Clemson University are collaborating to determine the applicability of laboratory empirical correlations between surface heat flux and thermal convection intensity. Laboratory experiments at Clemson University have demonstrated a simple relationship between the surface heat flux and the standard deviation of temperature fluctuations. Similar results were observed in the aerial thermal imagery SRNL collected at different locations along the thermal plume and at different elevations. SRNL will present evidence that the results at Clemson University are applicable to cooling lakes.

  15. An analytical coarse-graining method which preserves the free energy, structural correlations, and thermodynamic state of polymer melts from the atomistic to the mesoscale

    E-Print Network [OSTI]

    J. McCarty; A. J. Clark; J. Copperman; M. G. Guenza

    2014-07-03T23:59:59.000Z

    Structural and thermodynamic consistency of coarse-graining models across multiple length scales is essential for the predictive role of multi-scale modeling and molecular dynamic simulations that use mesoscale descriptions. Our approach is a coarse-grained model based on integral equation theory, which can represent polymer chains at variable levels of chemical details. The model is analytical and depends on molecular and thermodynamic parameters of the system under study, as well as on the direct correlation function in the k --> 0 limit, c0. A numerical solution to the PRISM integral equations is used to determine c0, by adjusting the value of the effective hard sphere diameter, d, to agree with the predicted equation of state. This single quantity parameterizes the coarse-grained potential, which is used to perform mesoscale simulations that are directly compared with atomistic-level simulations of the same system. We test our coarse-graining formalism by comparing structural correlations, isothermal compressibility, equation of state, Helmholtz and Gibbs free energies, and potential energy and entropy using both united atom and coarse-grained descriptions. We find quantitative agreement between the analytical formalism for the thermodynamic properties, and the results of Molecular Dynamics simulations, independent of the chosen level of representation. In the mesoscale description, the potential energy of the soft-particle interaction becomes a free energy in the coarse-grained coordinates which preserves the excess free energy from an ideal gas across all levels of description. The structural consistency between the united-atom and mesoscale descriptions means the relative entropy between descriptions has been minimized without any variational optimization parameters. The approach is general and applicable to any polymeric system in different thermodynamic conditions.

  16. An analytical coarse-graining method which preserves the free energy, structural correlations, and thermodynamic state of polymer melts from the atomistic to the mesoscale

    SciTech Connect (OSTI)

    McCarty, J.; Clark, A. J.; Copperman, J.; Guenza, M. G., E-mail: mguenza@uoregon.edu [Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403 (United States)

    2014-05-28T23:59:59.000Z

    Structural and thermodynamic consistency of coarse-graining models across multiple length scales is essential for the predictive role of multi-scale modeling and molecular dynamic simulations that use mesoscale descriptions. Our approach is a coarse-grained model based on integral equation theory, which can represent polymer chains at variable levels of chemical details. The model is analytical and depends on molecular and thermodynamic parameters of the system under study, as well as on the direct correlation function in the k ? 0 limit, c{sub 0}. A numerical solution to the PRISM integral equations is used to determine c{sub 0}, by adjusting the value of the effective hard sphere diameter, d{sub HS}, to agree with the predicted equation of state. This single quantity parameterizes the coarse-grained potential, which is used to perform mesoscale simulations that are directly compared with atomistic-level simulations of the same system. We test our coarse-graining formalism by comparing structural correlations, isothermal compressibility, equation of state, Helmholtz and Gibbs free energies, and potential energy and entropy using both united atom and coarse-grained descriptions. We find quantitative agreement between the analytical formalism for the thermodynamic properties, and the results of Molecular Dynamics simulations, independent of the chosen level of representation. In the mesoscale description, the potential energy of the soft-particle interaction becomes a free energy in the coarse-grained coordinates which preserves the excess free energy from an ideal gas across all levels of description. The structural consistency between the united-atom and mesoscale descriptions means the relative entropy between descriptions has been minimized without any variational optimization parameters. The approach is general and applicable to any polymeric system in different thermodynamic conditions.

  17. SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY

    SciTech Connect (OSTI)

    Zhang Chunguang; Deng Licai [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xiong Darun [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Christensen-Dalsgaard, Jorgen, E-mail: cgzhang@nao.cas.cn [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)

    2012-11-01T23:59:59.000Z

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  18. Damping of Type I X-ray Burst Oscillations by Convection

    E-Print Network [OSTI]

    Randall L. Cooper

    2008-03-26T23:59:59.000Z

    I construct a simple model of the convective burning layer during a type I X-ray burst to investigate the effects convection has on the stability of the layer to nonradial oscillations. A linear perturbation analysis demonstrates that the region is stable to nonradial oscillations when energy transport is convection-dominated, but it is unstable when energy transport is radiation-dominated. Thus, efficient convection always dampens oscillations. These results may explain the nondetection of oscillations during the peak of some X-ray bursts.

  19. E-Print Network 3.0 - axially focusing convection Sample Search...

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

    wall. The results show that the laminar forced convective heat transfer inside the tube never Source: Zhang, Yuwen - Department of Mechanical and Aerospace Engineering,...

  20. Development of advanced cloud parameterizations to examine air quality, cloud properties, and cloud-radiation feedback in mesoscale models

    SciTech Connect (OSTI)

    Lee, In Young

    1993-09-01T23:59:59.000Z

    The distribution of atmospheric pollutants is governed by dynamic processes that create the general conditions for transport and mixing, by microphysical processes that control the evolution of aerosol and cloud particles, and by chemical processes that transform chemical species and form aerosols. Pollutants emitted into the air can undergo homogeneous gas reactions to create a suitable environment for the production by heterogeneous nucleation of embryos composed of a few molecules. The physicochemical properties of preexisting aerosols interact with newly produced embryos to evolve by heteromolecular diffusion and coagulation. Hygroscopic particles wig serve as effective cloud condensation nuclei (CCN), while hydrophobic particles will serve as effective ice-forming nuclei. Clouds form initially by condensation of water vapor on CCN and evolve in a vapor-liquid-solid system by deposition, sublimation, freezing, melting, coagulation, and breakup. Gases and aerosols that enter the clouds undergo aqueous chemical processes and may acidity hydrometer particles. Calculations for solar and longwave radiation fluxes depend on how the respective spectra are modified by absorbers such as H{sub 2}O, CO{sub 2}, O{sub 3}, CH{sub 4}, N{sub 2}O, chlorofruorocarbons, and aerosols. However, the flux calculations are more complicated for cloudy skies, because the cloud optical properties are not well defined. In this paper, key processes such as tropospheric chemistry, cloud microphysics parameterizations, and radiation schemes are reviewed in terms of physicochemical processes occurring, and recommendations are made for the development of advanced modules applicable to mesoscale models.

  1. Climatology and Formation of Tropical Midlevel Clouds at the Darwin ARM Site

    SciTech Connect (OSTI)

    Riihimaki, Laura D.; McFarlane, Sally A.; Comstock, Jennifer M.

    2012-10-01T23:59:59.000Z

    A 4-yr climatology of midlevel clouds is presented from vertically pointing cloud lidar and radar measurements at the Atmospheric Radiation Measurement Program (ARM) site at Darwin, Australia. Few studies exist of tropical midlevel clouds using a dataset of this length. Seventy percent of clouds with top heights between 4 and 8 km are less than 2 km thick. These thin layer clouds have a peak in cloud-top temperature around the melting level (0įC) and also a second peak around -12.5įC. The diurnal frequency of thin clouds is highest during the night and reaches a minimum around noon, consistent with variation caused by solar heating. Using a 1.5-yr subset of the observations, the authors found that thin clouds have a high probability of containing supercooled liquid water at low temperatures: ~20% of clouds at -30įC, ~50% of clouds at -20įC, and ~65% of clouds at -10įC contain supercooled liquid water. The authors hypothesize that thin midlevel clouds formed at the melting level are formed differently during active and break monsoon periods and test this over three monsoon seasons. A greater frequency of thin midlevel clouds are likely formed by increased condensation following the latent cooling of melting during active monsoon periods when stratiform precipitation is most frequent. This is supported by the high percentage (65%) of midlevel clouds with preceding stratiform precipitation and the high frequency of stable layers slightly warmer than 0įC. In the break monsoon, a distinct peak in the frequency of stable layers at 0įC matches the peak in thin midlevel cloudiness, consistent with detrainment from convection.

  2. Geographic variation in vulnerability to climate warming in a tropical Caribbean lizard

    E-Print Network [OSTI]

    Leal, Manuel S.

    Geographic variation in vulnerability to climate warming in a tropical Caribbean lizard Alex R temperatures (Tb) of the tropical Caribbean lizard Anolis cristatellus at nine sites representing two habitat

  3. Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model

    E-Print Network [OSTI]

    Tang, Brian

    The sensitivity of tropical cyclone intensity to ventilation of cooler, drier air into the inner core is examined using an axisymmetric tropical cyclone model with parameterized ventilation. Sufficiently strong ventilation ...

  4. Tropical climate variability from the last glacial maximum to the present

    E-Print Network [OSTI]

    Dahl, Kristina Ariel

    2005-01-01T23:59:59.000Z

    This thesis evaluates the nature and magnitude of tropical climate variability from the Last Glacial Maximum to the present. The temporal variability of two specific tropical climate phenomena is examined. The first is the ...

  5. Vertical flux, ecology and dissolution of radiolaria in tropical oceans : implications for the silica cycle

    E-Print Network [OSTI]

    Takahashi, Kozo

    1982-01-01T23:59:59.000Z

    Radiolarians which settle through the oceanic water column were recovered from three stations (western Tropical Atlantic-Station E, central Tropical Pacific-P1 and Panama Basin-PB) using PARFLUX sediment traps in moored ...

  6. GCM simulation of the tropical mixing barriers in the lower stratosphere

    E-Print Network [OSTI]

    Hu, Yongyun

    1996-01-01T23:59:59.000Z

    of the tropical easterly zonal flow and subtropical wave spectra. Wave spectrum analysis indicates that during the solstitial seasons there exists a zone in the tropics, which exactly matches the weak mixing zone, where there is relatively absence of westward...

  7. The rainfall over tropical South America generated by multiple scale processes.

    E-Print Network [OSTI]

    Carrillo, Carlos Mauricio

    2010-01-01T23:59:59.000Z

    ??The rainfall regime over Central America and tropical South America is the most important hydro-meteorological event in the tropics after the Asian-Australian monsoon system. Therefore,Ö (more)

  8. Climate regulation of humid tropical hydrology BHS 10th National Hydrology Symposium, Exeter, 2008

    E-Print Network [OSTI]

    Chappell, Nick A

    might influence tropical water resources. Introduction The humid tropics can be defined as the global, Bangladesh, and most of South-east Asia (Fosberg et al., 1961). Its climate contains distinctive dynamics

  9. The Role of Mineralogy in Organic Matter Stabilization in Tropical Soils

    E-Print Network [OSTI]

    Sparks, Donald L.

    The Role of Mineralogy in Organic Matter Stabilization in Tropical Soils Wipawan Thaymuang,1 Irb) and mineralogy. This study investigated the mineral properties and OM stabilization in 12 surface tropical soil

  10. SRS reactor control rod cooling without normal forced convection cooling

    SciTech Connect (OSTI)

    Smith, D.C. (SAIC, Albuquerque, NM (United States)); Easterling, T.C. (Westinghouse Savannah River Co., Aiken, SC (United States))

    1993-01-01T23:59:59.000Z

    This paper describes an analytical study of the coolability of the control rods in the Savannah River site (SRS) K production reactor under conditions of loss of normal forced convection cooling. The study was performed as part of the overall safety analysis of the reactor supporting its restart. The analysis addresses the buoyancy-driven boiling flow over the control rods that occurs when forced cooling is lost. The objective of the study was to demonstrate that the control rods will remain cooled (i.e., no melting) at powers representative of those anticipated for restart of the reactor.

  11. Gradients of meteorological parameters in convective and nonconvective areas

    E-Print Network [OSTI]

    McCown, Milton Samuel

    1976-01-01T23:59:59.000Z

    . SYNOPTIC CONDITIONS 4. STRATIFICATION OF DATA 5. COMPUTATIONAL PROCEDURES 21 25 a. Gridding of rawinsonde data 25 b. Gradients 26 5'' lp t* 27 RESULTS 29 a. Gradients 29 1) Convective areas 29 2) Nonconvective areas 31 3) Combined areas 33 vi... air turbulence. By using airplane data from over the western United States, Scoggins (1975) has shown that CAT at 300 mb occurred 71% of the time when the magnitude of the vector horizontal wind shear -5 -1 exceeded 4. 5 x 10 sec . The horizontal...

  12. Generation of large-scale winds in horizontally anisotropic convection

    E-Print Network [OSTI]

    von Hardenberg, J; Provenzale, A; Spiegel, E A

    2015-01-01T23:59:59.000Z

    We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.

  13. Natural convection in high heat flux tanks at the Hanford Waste Site / [by] Mark van der Helm and Mujid S. Kazimi

    E-Print Network [OSTI]

    Van der Helm, Mark Johan, 1972-

    1996-01-01T23:59:59.000Z

    A study was carried out on the potential for natural convection and the effect of natural convection in a High Heat Flux Tank, Tank 241-C-106, at the Hanford Reservation. To determine the existence of natural convection, ...

  14. Tropical cyclone motion and recurvature in TCM-90. Master's thesis

    SciTech Connect (OSTI)

    Fitzpatrick, M.E.

    1992-01-01T23:59:59.000Z

    Rawinsonde and satellite data collected during the Tropical Cyclone Motion (TCM90) experiment, which was conducted during the summer of 1990 in the Western North pacific, is used to examine tropical cyclone steering motion and recurvature. TCM-90 composite results are compared with those found in a composite study using twenty-one years (1957-77) of Western North Pacific rawinsonde data during the same August-September period and also for all months during this same 21-year period. Both data sets indicate that the composite deep-layer-mean (850-300 mb) winds 5-7 deg from the cyclone center provide an important component of the steering flow for tropical cyclones. However, despite the rawinsonde data enhancements of the TCM-90 experiment, data limitations prevented an accurate observation of steering flow conditions at individual time periods or for the average of only 5-10 time periods when composited together.

  15. Convection induced by radiative cooling of a layer of participating medium

    SciTech Connect (OSTI)

    Prasanna, Swaminathan, E-mail: prasannaswam@gmail.com [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France)] [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France); Venkateshan, S. P., E-mail: spv@iitm.ac.in [HTTP Laboratory, Department of Mechanical Engineering IIT Madras, Chennai (India)

    2014-05-15T23:59:59.000Z

    Simulations and experiments have been conducted to study the effect of radiative cooling on natural convection in a horizontal layer of a participating medium enclosed between isothermal opaque wall and radiatively transparent wall and exposed to a cold background. The study is of relevance to a nocturnal boundary layer under clear and calm conditions. The focus of the study is to capture the onset of convection caused by radiative cooling. The experiments have been designed to mimic the atmospheric radiative boundary conditions, and hence decoupling convection and radiation boundary conditions. Planck number Pl and optical thickness of the layer ?{sub H} are the two important parameters that govern the interaction between radiation and convection. The radiation-convection coupling is a strong function of length scale. Convection sets up within first few seconds for all the experiments. Strong plume like convection is observed for the experimental conditions used in the present study. Both simulations and experiments confirm that radiative cooling increases substantially with decrease in emissivity of the bottom wall. Radiative cooling is strongly influenced by the nongray nature of the participating medium, especially when strong emission from the medium escapes to space, in the window region of the atmosphere. Accurate representation of radiative properties is critical. Linear stability analysis of onset of convection indicates that radiation stabilizes convection as Pl decreases. The observations are similar to the case of Rayleigh Bťnard convection in a radiating gas. However, for both experimental and numerical conditions, the observed Rayleigh numbers are much greater than the critical Rayleigh number. To conclude, the role of radiation is to drive and sustain convection in the unstable layer.

  16. Tropical forest responses to increasing atmospheric CO2: current knowledge and opportunities for future research

    E-Print Network [OSTI]

    Bermingham, Eldredge

    their representation in Earth system models. Tropical forests play a significant role in the global carbon cycle

  17. An optimizing reduced order FDS for the tropical Pacific Ocean reduced gravity model

    E-Print Network [OSTI]

    Aluffi, Paolo

    An optimizing reduced order FDS for the tropical Pacific Ocean reduced gravity model Zhendong Luoa) for the tropical Pacific Ocean reduced gravity model. Ensembles of data are compiled from transient solutions computed from the discrete equation system derived by FDS for the tropical Pacific Ocean reduced gravity

  18. Reduced Order Modeling of the Upper Tropical Pacific Ocean Model Using Proper Orthogonal Decomposition

    E-Print Network [OSTI]

    Aluffi, Paolo

    Reduced Order Modeling of the Upper Tropical Pacific Ocean Model Using Proper Orthogonal of a large-scale upper ocean circulation in the tropic Pacific domain. We construct different POD models-scale seasonal variability of the tropic Pacific obtained by the original model is well captured by a low

  19. Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean

    E-Print Network [OSTI]

    Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean: 2] Eddy diffusivity of the surface velocity field in the tropical Pacific Ocean was estimated using diffusivity estimates in the tropical Pacific Ocean: 2. Results, J. Geophys. Res., 107(C10), 3154, doi:10

  20. Regional feedbacks among fire, climate, and tropical deforestation William A. Hoffmann1

    E-Print Network [OSTI]

    Jackson, Robert B.

    Regional feedbacks among fire, climate, and tropical deforestation William A. Hoffmann1 December 2003. [1] Numerous studies with general circulation models suggest that tropical deforestation can to estimate the effect of tropical deforestation on fire risk through the McArthur forest fire danger index

  1. Interhemispheric Teleconnections from Tropical Heat Sources in Intermediate and Simple Models

    E-Print Network [OSTI]

    the prescribed tropical heating in both intensity and geographical extent and by inducing remote precipitation anomalies by interaction with the basic state. 1. Introduction Tropical heat sources can remotely influenceInterhemispheric Teleconnections from Tropical Heat Sources in Intermediate and Simple Models XUAN

  2. Tropical Forestry Researchat the USDA Forest Service's Instituteof Pacific Islands Forestry1

    E-Print Network [OSTI]

    Standiford, Richard B.

    Tropical Forestry Researchat the USDA Forest Service's Instituteof Pacific Islands Forestry1 C greater emphasis on tropical forestry management and research was provided by the International Forestry Islands Forestry in Hawaii, the Institute of Tropical Forestry in Puerto Rico, and the U S . Forest

  3. Interactions between the tropical ISO and midlatitude low-frequency flow

    E-Print Network [OSTI]

    Li, Tim

    Interactions between the tropical ISO and midlatitude low-frequency flow Lin-Lin Pan ∆ Tim Li Abstract In this study, we investigate the interaction between the tropical Intraseasonal Oscillation (ISO study the role of the syn- optic eddy feedback in the midlatitude response to the tropical ISO forcing

  4. Developing versus Nondeveloping Disturbances for Tropical Cyclone Formation. Part I: North Atlantic*

    E-Print Network [OSTI]

    Li, Tim

    Developing versus Nondeveloping Disturbances for Tropical Cyclone Formation. Part I: North Atlantic the characteristic differences of tropical disturbances that eventually develop into tropical cyclones (TCs) versus for TC genesis in the North Atlantic. When the east and west (separated by 408W) Atlantic are examined

  5. Notes and Correspondence Are Tropical Cyclones Less Effectively Formed by Easterly Waves in the

    E-Print Network [OSTI]

    Chen, Tsing-Chang "Mike"

    tropical cyclones in the western North Pacific. By carefully separating easterly waves from the lowerNotes and Correspondence Are Tropical Cyclones Less Effectively Formed by Easterly Waves@iastate.edu #12;1 Abstract It has been observed that the percentage of tropical cyclones originating from easterly

  6. Global warming shifts Pacific tropical cyclone location MinHo Kwon,1,3

    E-Print Network [OSTI]

    Li, Tim

    Global warming shifts Pacific tropical cyclone location Tim Li,1 MinHo Kwon,1,3 Ming Zhao,3 Jong) is used to investigate the change of tropical cyclone frequency in the North Pacific under global warming, and W. Yu (2010), Global warming shifts Pacific tropical cyclone location, Geophys. Res. Lett., 37, L

  7. A Simple Atmospheric Model of the Local and Teleconnection Responses to Tropical Heating Anomalies

    E-Print Network [OSTI]

    Wang, Chunzai

    the local and remote stationary responses of the atmosphere to tropical heating anomalies is describedA Simple Atmospheric Model of the Local and Teleconnection Responses to Tropical Heating Anomalies and forced with a localized heating for illustration. In the tropics, the baroclinic responses are familiar

  8. Validating Atmospheric Reanalysis Data Using Tropical Cyclones as Thermometers James P. Kossin

    E-Print Network [OSTI]

    Kossin, James P.

    1 Validating Atmospheric Reanalysis Data Using Tropical Cyclones as Thermometers James P. Kossin tropical cyclones as thermometers. Bull. Amer. Meteor. Soc. doi:10.1175/BAMS-D-14-00180, in press. Capsule Tropical cyclones are used as traveling thermometers to globally sample upper-tropospheric temperatures

  9. The divergent wind component in data sparse tropical wind fields

    E-Print Network [OSTI]

    Snyder, Bruce Alan

    1985-01-01T23:59:59.000Z

    THE DIVERGENT WIND COMPONENT IN DATA SPARSE TROPICAL WIND FIELDS A Thesis by BRUCE ALAN SNYDER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December... 1985 Major Subject: Meteorology THE DIVERGENT WIND COMPONENT IN DATA SPARSE TROPICAL WIND FIELDS A Thesis by BRUCE ALAN SNYDER Approved as to style and content by: James P. McGuirk (Co-Chairman) Aylmer IL Thompson (Co-Chairman) W. Homer...

  10. Diurnal Cycle of Convection at the ARM SGP Site: Role of Large-Scale Forcing, Surface Fluxes, and Convective Inhibition

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesDataTranslocationDiurnal Cycle of Convection at the ARM SGP Site:

  11. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

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

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  12. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    SciTech Connect (OSTI)

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19T23:59:59.000Z

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  13. Heat transport measurements in turbulent rotating Rayleigh-Benard convection

    SciTech Connect (OSTI)

    Ecke, Robert E [Los Alamos National Laboratory; Liu, Yuanming [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    We present experimental heat transport measurements of turbulent Rayleigh-Benard convection with rotation about a vertical axis. The fluid, water with Prandtl number ({sigma}) about 6, was confined in a cell which had a square cross section of 7.3 cm x 7.3 cm and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers 2 x 10{sup 5} < Ra < 5 x 10{sup 8} and Taylor numbers 0 < Ta < 5 x 10{sup 9}. We show the variation of normalized heat transport, the Nusselt number, at fixed dimensional rotation rate {Omega}{sub D}, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range 10{sup 7} to about 10{sup 9} is roughly 0.29 with a Ro dependent coefficient or equivalently is also well fit by a combination of power laws of the form a Ra{sup 1/5} + b Ra{sup 1/3} . The range of Ra is not sufficient to differentiate single power law or combined power law scaling. The overall impact of rotation on heat transport in turbulent convection is assessed.

  14. Kinetics of the clay roofing tile convection drying

    SciTech Connect (OSTI)

    Thomas, S. (Univ. of Osijek (Croatia). Faculty of Food Technology); Skansi, D. (Univ. of Zagreb (Croatia). Faculty of Chemical Engineering and Technology); Sokele, M. (Croatian Post and Telecommunications, Zagreb (Croatia). Telecommunications Center)

    1993-01-01T23:59:59.000Z

    Kinetics of the convection drying process of flat tile has been investigated experimentally in an industrial tunnel dryer. Several velocities of wet tile movement through the dryer were tested to obtain maximum allowable drying rate curve. As there are various models to describe the kinetics of convection drying, finding a model that would fairly well approximate the kinetics of the whole drying process was part of the research. Especially the polynomial and exponential models were tested. It was found that exponential model of the type: B(t) = (a[minus]B[sub e])[center dot]EXP([minus]bt[sup 2])+B[sub e], ([minus]dB(t)/dt) = 2bt(B(t)[minus]B[sub e]) significantly correlates the kinetics of the whole tile drying process. Applying the maximum allowable drying rate curve obtained for flat tile in the first period of drying, a grapho-analytic model for the optimal conducting of the process has been developed.

  15. A Multiscale Dynamo Model Driven by Quasi-geostrophic Convection

    E-Print Network [OSTI]

    Calkins, Michael A; Tobias, Steven M; Aurnou, Jonathan M

    2015-01-01T23:59:59.000Z

    A convection-driven multiscale dynamo model is developed for the plane layer geometry in the limit of low Rossby number. The small-scale fluctuating dynamics are described by a magnetically-modified quasi-geostrophic equation set, and the large-scale mean dynamics are governed by a diagnostic thermal wind balance. The model utilizes three timescales that respectively characterize the convective timescale, the large-scale magnetic diffusion timescale, and the large-scale thermal diffusion timescale. Distinct equations are derived for the cases of order one and low magnetic Prandtl number. It is shown that the low magnetic Prandtl number model is characterized by a magnetic to kinetic energy ratio that is asymptotically large, with ohmic dissipation dominating viscous dissipation on the large-scales. For the order one magnetic Prandtl number model the magnetic and kinetic energies are equipartitioned and both ohmic and viscous dissipation are weak on the large-scales; large-scale ohmic dissipation occurs in thi...

  16. Particle filter based on thermophoretic deposition from natural convection flow

    SciTech Connect (OSTI)

    Sasse, A.G.B.M.; Nazaroff, W.W. (Univ. of California, Berkeley, CA (United States)); Gadgil, A.J. (Lawrence Berkeley Lab., CA (United States))

    1994-04-01T23:59:59.000Z

    We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.

  17. Simulated Convective Invigoration Processes at Trade Wind Cumulus Cold Pool ZHUJUN LI AND PAQUITA ZUIDEMA

    E-Print Network [OSTI]

    Zuidema, Paquita

    convection and cold pools using a nested≠Weather Research and Fore- casting Model simulation of 19 January ratio drops in simulated cold pools fall within the envelope of observed cases, and the wind enhancement pools invigorating convection at their downwind boundary and suppressing thermals in- side the stable

  18. Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model

    SciTech Connect (OSTI)

    Zhang, Guang J [Scripps Institution of Oceanography

    2013-07-29T23:59:59.000Z

    Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

  19. Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth

    E-Print Network [OSTI]

    Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth C, in particular, on its variation with the wavelength of convection. The heat transfer strongly depends in Earth's mantle can significantly reduce the efficiency of heat transfer. The likely variations

  20. Modelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove

    E-Print Network [OSTI]

    value energy conversions such as heat engine cycles or chemical process to be carried outModelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove, Canberra AUSTRALIA E-mail: u3370739@anu.edu.au The natural convective flow inside a concentrating solar

  1. Numerical study of natural convection in a vertical porous annulus with discrete heating

    E-Print Network [OSTI]

    Lopez, John M.

    ≠10]. Among the finite enclosures, free convective heat transfer in a differentially heated vertical porous in a vertical annular enclosure for a wide range of radius and aspect ratios, and also used an approximateNumerical study of natural convection in a vertical porous annulus with discrete heating M. Sankar

  2. Numerical Investigation of Natural Convection Loss in Cavity-Type Solar Receivers

    E-Print Network [OSTI]

    Work There have been several previous investigations of natural convection heat loss from open the convective heat loss, i.e., (i) the ability to transfer mass and energy across the aperture and (ii to investigate three cases of geometrically different receivers. The calculated heat loss results shows

  3. Dielectrophoretic Rayleigh-Benard convection under microgravity conditions H. N. Yoshikawa,

    E-Print Network [OSTI]

    Paris-Sud XI, Universitť de

    conditions. A thermo-electric coupling resulting from the thermal variation of the electric permittivity of the fluid produces the dielectrophoretic (DEP) body force, which can be regarded as thermal buoyancy due of the GL equation are comparable with those for the RB convection. The heat transfer in the DEP convection

  4. The impact of methane thermodynamics on seasonal convection and circulation in a model Titan atmosphere

    E-Print Network [OSTI]

    Caballero, Rodrigo

    The impact of methane thermodynamics on seasonal convection and circulation in a model Titan mechanisms controlling the distribution of methane convection and large-scale circulation in a simplified, axisymmetric model atmosphere of Titan forced by gray radiation and moist (methane) con- vection. The large

  5. Pattern formation in binary mixture convection in cylindrical three-dimensional cells

    E-Print Network [OSTI]

    Batiste, Oriol

    present numerical results of pattern selection near the onset of convection for a water-ethanol mixture of the cell is = 11. The onset of convection occurs via a subcritical Hopf bifurcation. Slightly above ratio mixtures, S subcritical and gives rise

  6. THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN

    E-Print Network [OSTI]

    Abbett, Bill

    THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN W. P. Abbett Space connection between the convectively unstable layers below the visible surface of the Sun and the overlying application of this numerical model, we present a series of simulations of the quiet Sun in a domain

  7. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    SciTech Connect (OSTI)

    Serrato, M. G.

    2013-09-27T23:59:59.000Z

    The DOE Office of Environmental management (DOE EM) faces the challenge of decommissioning thousands of excess nuclear facilities, many of which are highly contaminated. A number of these excess facilities are massive and robust concrete structures that are suitable for isolating the contained contamination for hundreds of years, and a permanent decommissioning end state option for these facilities is in situ decommissioning (ISD). The ISD option is feasible for a limited, but meaningfull number of DOE contaminated facilities for which there is substantial incremental environmental, safety, and cost benefits versus alternate actions to demolish and excavate the entire facility and transport the rubble to a radioactive waste landfill. A general description of an ISD project encompasses an entombed facility; in some cases limited to the blow-grade portion of a facility. However, monitoring of the ISD structures is needed to demonstrate that the building retains its structural integrity and the contaminants remain entombed within the grout stabilization matrix. The DOE EM Office of Deactivation and Decommissioning and Facility Engineering (EM-13) Program Goal is to develop a monitoring system to demonstrate long-term performance of closed nuclear facilities using the ISD approach. The Savannah River National Laboratory (SRNL) has designed and implemented the In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) to address the feasibility of deploying a long-term monitoring system into an ISD closed nuclear facility. The ISDSN-MSTB goal is to demonstrate the feasibility of installing and operating a remote sensor network to assess cementitious material durability, moisture-fluid flow through the cementitious material, and resulting transport potential for contaminate mobility in a decommissioned closed nuclear facility. The original ISDSN-MSTB installation and remote sensor network operation was demonstrated in FY 2011-12 at the ISDSN-MSTB test cube located at the Florida International University Applied Research Center, Miami, FL (FIU-ARC). A follow-on fluid injection test was developed to detect fluid and ion migration in a cementitious material/grouted test cube using a limited number of existing embedded sensor systems. This In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) - Phase 3 Fluid Injection Test Summary Report summarizes the test implementation, acquired and processed data, and results from the activated embedded sensor systems used during the fluid injection test. The ISDSN-MSTB Phase 3 Fluid Injection Test was conducted from August 27 through September 6, 2013 at the FIU-ARC ISDSN-MSTB test cube. The fluid injection test activated a portion of the existing embedded sensor systems in the ISDSN-MSTB test cube: Electrical Resistivity Tomography-Thermocouple Sensor Arrays, Advance Tensiometer Sensors, and Fiber Loop Ringdown Optical Sensors. These embedded sensor systems were activated 15 months after initial placement. All sensor systems were remotely operated and data acquisition was completed through the established Sensor Remote Access System (SRAS) hosted on the DOE D&D Knowledge Management Information Tool (D&D DKM-IT) server. The ISDN Phase 3 Fluid Injection Test successfully demonstrated the feasibility of embedding sensor systems to assess moisture-fluid flow and resulting transport potential for contaminate mobility through a cementitious material/grout monolith. The ISDSN embedded sensor systems activated for the fluid injection test highlighted the robustness of the sensor systems and the importance of configuring systems in-depth (i.e., complementary sensors and measurements) to alleviate data acquisition gaps.

  8. 3D Simulation of Convection and Spectral Line Formation in A-type Stars

    E-Print Network [OSTI]

    M. Steffen; B. Freytag; H. -G. Ludwig

    2005-09-15T23:59:59.000Z

    We present first realistic numerical simulations of 3D radiative convection in the surface layers of main sequence A-type stars with Teff = 8000 K and 8500 K, log g = 4.4 and 4.0, recently performed with the CO5BOLD radiation hydrodynamics code. The resulting models are used to investigate the structure of the H+HeI and the HeII convection zones in comparison with the predictions of local and non-local convection theories, and to determine the amount of "overshoot" into the stable layers below the HeII convection zone. The simulations also predict how the topology of the photospheric granulation pattern changes from solar to A-type star convection. The influence of the photospheric temperature fluctuations and velocity fields on the shape of spectral lines is demonstrated by computing synthetic line profiles and line bisectors for some representative examples, allowing us to confront the 3D model results with observations.

  9. Transformed shoreline-following horizontal coordinates in a mesoscale model: A sea-land-breeze case study

    SciTech Connect (OSTI)

    Berri, G.J.; Nunez, M.N. (Universidad de Buenos Aires (Argentina) Pabellon II Ciudad Universitaria, Buenos Aires (Argentina))

    1993-05-01T23:59:59.000Z

    A hydrostatic and incompressible mesoscale model with transformed horizontal coordinates is presented. The model is applied to study the sea-land-breeze circulation over Rio de La Plata. One of the new coordinates is shoreline-following and the other one is locally quasi-perpendicular to the first one. The original set of equations in the Cartesian coordinates is rewritten in the curvilinear coordinates. This transformation is useful provided that the curvilinear coordinates are close to being orthogonal. The horizontal domain covers 250 km [times] 250 km, and the vertical domain is 2 km deep. To predict the sea-land-breeze circulation the model is integrated over 12 h. The forcing of the model is a cyclic perturbation of the surface temperature. The changes in the wind direction during the day are in good agreement with the observations from six weather stations in the region. The same program code is applied to uniform domains of different resolutions in order to test the coordinate transformation. Results show that the predictions based upon the variable-resolution version resemble ones obtained using high uniform resolution but consume only one-fourth the computer time needed by the latter. Comparison of the vertical velocity patterns predicted by the model to the cumulus clouds distribution observed from satellite images show a very good agreement too. The authors believe that all these results justify the use of the coordinate transformation in this type of model, although further verifications are needed in order to draw more definitive conclusions. 28 refs., 11 figs.

  10. NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED BUILDING ENERGY AND CFD SIMULATION

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED

  11. Magnetospheric Convection The large-scale flow of rarefied plasma in the Earth's magnetosphere "is quite analogous to

    E-Print Network [OSTI]

    Michigan, University of

    quite analogous to thermal convection" (Gold, 1959); therefore, the term "convection" is commonly used of geomagnetic field lines in the crossed E and B fields. By analogy with the thermal convection in a non in the magnetosheath: a region between the bow shock and the magnetopause. A similar flow pattern is formed

  12. Orogenic Convection in Subtropical South America as Seen by the TRMM Satellite KRISTEN L. RASMUSSEN AND ROBERT A. HOUZE JR.

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    Orogenic Convection in Subtropical South America as Seen by the TRMM Satellite KRISTEN L. RASMUSSEN storms in southeastern South America are divided into three categories: storms with deep convective cores, the intense storms with wide convective cores over southeastern South America are unlike their Himalayan

  13. TROPICAL MULTIPLICATION MAPS AND THE GIESEKER-PETRI THEOREM

    E-Print Network [OSTI]

    Payne, Sam

    TROPICAL MULTIPLICATION MAPS AND THE GIESEKER-PETRI THEOREM DAVID JENSEN AND SAM PAYNE Abstract. We. Supported in part by NSF grants DMS≠1068689 and CAREER DMS≠1149054. 1 #12;2 DAVID JENSEN AND SAM PAYNE v1 w1 by the addition or deletion of a bridge are canonically isomorphic, and these isomorphisms respect the images of the

  14. Fungal endophytes limit pathogen damage in a tropical tree

    E-Print Network [OSTI]

    Bermingham, Eldredge

    Fungal endophytes limit pathogen damage in a tropical tree A. Elizabeth Arnold* , Luis Carlos Meji species examined to date harbors endophytic fungi within its asymptomatic aerial tissues, such that endophytes rep- resent a ubiquitous, yet cryptic, component of terrestrial plant communities. Fungal

  15. Global Patterns of Ecological Productivity and Tropical Forest Biomass

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    those measurements in addition to climate data to construct a suite of empirical models of NPP productivity (NPP) on a global scale and biomass accumulation across thee tropics. Scientists have been model of terrestrial net primary productivity (NPP), and its simplicity and relative accuracy has led

  16. A QuikSCAT climatology of tropical cyclone size

    E-Print Network [OSTI]

    Chavas, Daniel Robert

    QuikSCAT data of near-surface wind vectors for the years 1999Ė2008 are used to create a climatology of tropical cyclone (TC) size, defined as the radius of vanishing winds. The azimuthally-averaged radius of 12 ms?1 [ms ...

  17. Low beta diversity of herbivorous insects in tropical forests

    E-Print Network [OSTI]

    Basset, Yves

    LETTERS Low beta diversity of herbivorous insects in tropical forests Vojtech Novotny1 , Scott E) and fruit (fruitflies, Diptera) found a low rate of change in species composition (beta diversity) across 75 of kilo- metres. Low beta diversity was also documented in groups with differing host specificity

  18. Variable Responses of Lowland Tropical Forest Nutrient Status

    E-Print Network [OSTI]

    Harms, Kyle E.

    Variable Responses of Lowland Tropical Forest Nutrient Status to to play a key role in nutrient retention. We discuss our findings in the context of possible impacts Springer Science+Business Media, LLC 387 #12;growth not only alters forests' nutrient demands but also

  19. Association for Tropical Biology and Conservation Brownsberg Declaration 2008

    E-Print Network [OSTI]

    Norconk, Marilyn A.

    Paramaribo, Suriname VERKLARING INZAKE HET TOEKENNEN VAN PERMANENT BESCHERMDE STATUS AAN DE BROWNSBERG EN DE. IN OVERWEGING NEMENDE DAT de bauxiethoudende Bergen in noordoost- Suriname ­ Brownsberg, Nassau en Lely ­ deelAssociation for Tropical Biology and Conservation Brownsberg Declaration 2008 13 June 2008

  20. TROPIC: Transactional Resource Orchestration Platform In the Cloud

    E-Print Network [OSTI]

    Plotkin, Joshua B.

    TROPIC: Transactional Resource Orchestration Platform In the Cloud Changbin Liu, Yun Mao*, Xu Chen ­ InfrastructureasaService (IaaS) Cloud · Provide cloud infrastructure services: virtual machines (VMs), virtual block devices, VPNs · Widely adopted, e.g. Amazon Elastic Compute Cloud (EC2) ­ Cloud resource

  1. Temporal Changes in a Tropical Nekton Assemblage and

    E-Print Network [OSTI]

    Temporal Changes in a Tropical Nekton Assemblage and Performance of a Prawn Selective Gear TING and weights of 39 trials conductedfor a selective prawning gear whose performance in bycatch reduc tionI., 1975; Rob erts, 1978; Allen and Coates, 1990), but is extremely rich in the marine coun terpart

  2. Detection of iodine monoxide in the tropical free troposphere

    E-Print Network [OSTI]

    19, 2012) Atmospheric iodine monoxide (IO) is a radical that catalytically destroys heat trapping in the remote tropical marine boundary layer (MBL) (2­4). IO further affects the oxidative capacity iodine species over the remote ocean remain poorly understood (11, 14) but are currently thought

  3. Arbuscular mycorrhizal mycelial respiration in a moist tropical forest

    E-Print Network [OSTI]

    Bermingham, Eldredge

    Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; 4 Ecological Farming Systems, Research Tropical Research Institute, 0843- 03092 Balboa, Ancon, Panama; 3 Institute of Ecological Science, Vrije Station ART, Swiss Federal Research Institute Agroscope, Zurich, Switzerland; 5 Plant­Microbe Interactions

  4. Environmental Factors Affecting Tropical Cyclone Power Dissipation KERRY EMANUEL

    E-Print Network [OSTI]

    Emanuel, Kerry A.

    - son 1974; Webster et al. 2005), and the Accumulated Cyclone Energy (ACE) index (Bell et al. 2000, the PDI is also accumulated over each year. Annually accumulated integral metrics such as ACE and PDI showEnvironmental Factors Affecting Tropical Cyclone Power Dissipation KERRY EMANUEL Program

  5. Tropical methane emissions: A revised view from SCIAMACHY onboard ENVISAT

    E-Print Network [OSTI]

    Haak, Hein

    Tropical methane emissions: A revised view from SCIAMACHY onboard ENVISAT Christian Frankenberg,1; accepted 26 June 2008; published 12 August 2008. [1] Methane retrievals from near-infrared spectra recorded spectroscopic parameters, causing a substantial overestimation of methane correlated with high water vapor

  6. Possible linkages between Saharan dust and tropical cyclone rain band invigoration in the eastern Atlantic during NAMMA-06

    E-Print Network [OSTI]

    Rutledge, Steven

    for tropical cyclogenesis, it also provides an infusion of cloud condensation and ice nuclei which can

  7. Accepted by Mon. Weather Rev. December 17, 1998. Convective Precursors and Predictability in the

    E-Print Network [OSTI]

    Sherwood, Steven

    in the Tropics are investigated by multivariate analysis of sounding and satellite data from the tropical western because it has been considered more complex and less well-understood than the activation problem, NASA Goddard Space Flight Center, Mail Code 916, Greenbelt, MD 20771 (ssherwood@alum.mit.edu) Many

  8. A Feasibility Study for Probabilistic Convection Initiation Forecasts Based on Explicit Numerical Guidance2

    E-Print Network [OSTI]

    Lakshmanan, Valliappa

    , Steven J. Weiss2 , Fanyou Kong4,5 , Ming Xue4,5 , Ryan A. Sobash1,4 , Andrew R. Dean2 , Israel L. Jirak2 ,6 and Christopher J. Melick2,3 8 1 NOAA/National Severe Storms Laboratory, Norman, OK10 2 NOAA/Storm Prediction Center, Norman, OK 3 Cooperative Institute for Mesoscale Meteorological Studies, Norman, OK12 4

  9. Stability of sunspots to convective motions. I. Adiabatic instability

    SciTech Connect (OSTI)

    Moreno-Insertis, F.; Spruit, H.C. (Instituto de Astrofisica de Canarias, La Laguna (Spain); Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.))

    1989-07-01T23:59:59.000Z

    For determining the adiabatic stability of a uniform vertical field in an arbitrary stratification it is sufficient to consider the limit of infinitesimal horizontal wavelength. It is shown how the behavior of the instability can be estimated qualitatively from the dependence of the equipartition field strength on depth. Modes are calculated numerically for analytic stratification models and for a detailed sunspot stratification, including the effects of partial ionization. It is concluded that for the observed field strengths of umbrae the stratification is indeed unstable, with a growth time of about 18 minutes. The unstable eigenfunctions have a maximum at about 2300 km below the surface of the umbra and are about 3900 km deep. Deeper layers may also be unstable depending on unknown details of the stratification. A connection between fluting instability and convective instability is noted. 37 refs.

  10. EFFECTS OF ASYMMETRIC FLOWS IN SOLAR CONVECTION ON OSCILLATION MODES

    SciTech Connect (OSTI)

    Baldner, Charles S.; Schou, Jesper, E-mail: baldner@stanford.edu [W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States)

    2012-11-20T23:59:59.000Z

    Many helioseismic measurements suffer from substantial systematic errors. A particularly frustrating one is that time-distance measurements suffer from a large center to limb effect which looks very similar to the finite light travel time, except that the magnitude depends on the observable used and can have the opposite sign. This has frustrated attempts to determine the deep meridional flow in the solar convection zone, with Zhao et al. applying an ad hoc correction with little physical basis to correct the data. In this Letter, we propose that part of this effect can be explained by the highly asymmetrical nature of the solar granulation which results in what appears to the oscillation modes as a net radial flow, thereby imparting a phase shift on the modes as a function of observing height and thus heliocentric angle.

  11. Wind reversals in turbulent Rayleigh-Benard convection

    E-Print Network [OSTI]

    Francisco Fontenele Araujo; S. Grossmann; D. Lohse

    2005-08-29T23:59:59.000Z

    The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \\leq \\Pr \\leq 10^{3}$ and $10^{7} \\leq \\Ra \\leq 10^{12}$, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as $\\Re_{rms} \\sim \\Ra^{[0.41 ... 0.47]}$ (depending on Pr), and as $\\Re_{rms} \\sim \\Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law $\\omega / (\

  12. Operating temperatures for a convectively cooled recessed incandescent light fixture

    SciTech Connect (OSTI)

    Yarbrough, D.W.; Toor, I.

    1980-12-01T23:59:59.000Z

    Test results are given for the operation of a recessed incandescent light fixture intended for residential use. The fixture is labeled for use in direct contact with attic thermal insulation. Temperature control of the powered fixture is provided by convective heat transfer from the ceiling side of the fixture. The fixture was operated at power levels up to two times the rated power of 75 watts and under thermal insulations up to R-40. In all operating configurations tested the fixture surface in contact with attic insulation was found to be less than 175/sup 0/C. The observed surface temperatures are judged to be safe for operation in contact with loose-fill or batt-type insulations. It was observed that the power leads inside one fixture configuration are exposed to temperatures as high as 168/sup 0/C. The electrical insulation could, therefore, have a limited life. The properties of the internal fixture wiring were not, however, studied in detail.

  13. Apparatus for production of synthesis gas using convective reforming

    SciTech Connect (OSTI)

    Karafian, M.; Tsang, I.C.

    1991-04-09T23:59:59.000Z

    This patent describes a system for the steam reforming of hydrocarbons into a hydrogen-rich gas. It comprises a convective reformer device having indirect heat exchange means for partially reforming a feed mixture of hydrocarbons and steam; a steam reforming furnace having a radiant section, reforming tubes in the radiant section, and means for producing radiant heat for the further reforming of the partially reformed effluent; an auto-thermal reformer for fully reforming the effluent; conduit means for passing the partially reformed effluent; conduit means for passing the effluent; and conduit means for passing the fully reformed effluent to supply the heat of reaction for the partial reformation of the hydrocarbon-steam feed mixture.

  14. The structure and dynamics of patterns of Benard convection cells

    SciTech Connect (OSTI)

    Rivier, N. (Argonne National Lab., IL (USA) Imperial Coll. of Science and Technology, London (UK). Blackett Lab. Lausanne Univ. (Switzerland). Inst. de Physique Experimentale)

    1990-08-01T23:59:59.000Z

    Benard-Marangoni convection, in containers with large aspect ratio, exhibits space-filling cellular structures, highly deformable, but crystallized. They contain dislocations and grain boundaries generated and moved by elementary topological transformations, and are subjected to a weak shear stress due to the earth's rotation. The cellular structure and its fluctuations are analyzed from a crystallographic viewpoint, by using two complementary approaches. One is a global analysis of cellular structures in cylindrical symmetry. Their structural stability and defect pattern are obtained as topological mode-locking of a continuous structural parameter. The other, a local, molecular dynamics of the cells, gives a realistic parametrization of the forces and the transformations by generalizing the Voronoi cell construction in one extra dimension. 23 refs., 8 figs.

  15. TURBULENT CONVECTION IN STELLAR INTERIORS. III. MEAN-FIELD ANALYSIS AND STRATIFICATION EFFECTS

    SciTech Connect (OSTI)

    Viallet, Maxime [Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); Meakin, Casey; Mocak, Miroslav [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Arnett, David [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-05-20T23:59:59.000Z

    We present three-dimensional implicit large eddy simulations of the turbulent convection in the envelope of a 5 M{sub Sun} red giant star and in the oxygen-burning shell of a 23 M{sub Sun} supernova progenitor. The numerical models are analyzed in the framework of one-dimensional Reynolds-Averaged Navier-Stokes equations. The effects of pressure fluctuations are more important in the red giant model, owing to larger stratification of the convective zone. We show how this impacts different terms in the mean-field equations. We clarify the driving sources of kinetic energy, and show that the rate of turbulent dissipation is comparable to the convective luminosity. Although our flows have low Mach numbers and are nearly adiabatic, our analysis is general and can be applied to photospheric convection as well. The robustness of our analysis of turbulent convection is supported by the insensitivity of the mean-field balances to linear mesh resolution. We find robust results for the turbulent convection zone and the stable layers in the oxygen-burning shell model, and robust results everywhere in the red giant model, but the mean fields are not well converged in the narrow boundary regions (which contain steep gradients) in the oxygen-burning shell model. This last result illustrates the importance of unresolved physics at the convective boundary, which governs the mixing there.

  16. Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array

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

    Xie, Shaocheng [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jensen, Michael P. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Zhang, Yunyan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Giangrande, Scott E. [Brookhaven National Laboratory (BNL), Upton, NY (United States); McCoy, Renata [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Zhang, Minghua [Stony Brook Univ., Stony Brook, NY (United States)

    2014-10-27T23:59:59.000Z

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during the morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. Sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.

  17. Physica D 143 (2000) 169186 Surface tension-driven convection patterns in two liquid layers

    E-Print Network [OSTI]

    Texas at Austin. University of

    Physica D 143 (2000) 169­186 Surface tension-driven convection patterns in two liquid layers Anne a liquid layer with a free surface is heated from below, both surface tension gradients and buoyancy may

  18. A visualization comparison of convective flow boiling heat transfer augmentation devices

    E-Print Network [OSTI]

    Lundy, Brian Franklin

    1998-01-01T23:59:59.000Z

    The qualitative effects of inset-table heat transfer phics. augmentation devices on vertical in-tube convective flow boiling flow regimes, transition mechanisms, and heat transfer are presented in this study. Three twisted tapes with twist ratios...

  19. Simulated diurnal rainfall physics in a multi-scale global climate model with embedded explicit convection

    E-Print Network [OSTI]

    Pritchard, Michael Stephen

    2011-01-01T23:59:59.000Z

    radiation-convection feedbacks are usually invoked to explain the open oceanocean] diurnal [rainfall] cycle can be qualita- tively accounted for by direct radiation-ocean is often maximized in the early morning hours, colloquially called the ďDynamic-Radiation-

  20. Numerical analysis of binary solid-liquid phase change with buoyancy and surface tension driven convection

    SciTech Connect (OSTI)

    Incropera, F.P.; Engel, A.H.H. (Purdue Univ., Lafayette, IN (USA). Heat Transfer Lab.); Bennon, W.D. (Alcoa Technical Center, Alcoa Center, PA (US))

    1989-01-01T23:59:59.000Z

    The effects of thermo/diffusocapillary convection on the solidification of aqueous NH{sub 4}Cl in a rectangular cavity have been simulated numerically using a newly developed continuum model. Diffusocapillary convection is negligible relative to thermocapillary convection, and for a 20 {times} 20 mm cavity in a one-gravity environment, thermocapillary effects are most pronounced during the early stages of solidification, when flow conditions are characterized by three major cells. One cell, driven by solutal buoyancy forces, extends from the mush region to the melt and separates top and bottom melt region cells driven primarily by surface tension and buoyancy forces, respectively. With increasing time, however, the top cell strengthens and eventually envelops the entire melt. In terms of the strength of the flow, the liquidus front morphology, and the amount of solid formed, final conditions differ only slightly from those predicted for pure thermal/solutal convection.

  1. Rheology and Convective Heat Transfer of Colloidal Gas Aphrons in Horizontal Minichannels

    E-Print Network [OSTI]

    Tseng, H.; Pilon, L.; Warrier, G.

    2006-01-01T23:59:59.000Z

    Single-phase convective heat transfer in microchannels: aand Newell, M. E. , 1967. Heat transfer in fully developed3 /s at 130 W. Water CGA Heat Transfer Coefficient, h (W/m 2

  2. Convective Heat Transfer Enhancement in Nanofluids: Real Anomaly or Analysis Artifact?

    E-Print Network [OSTI]

    Prabhat, Naveen

    The nanofluid literature contains many claims of anomalous convective heat transfer enhancement in both turbulent and laminar flow. To put such claims to the test, we have performed a critical detailed analysis of the ...

  3. Thermal perturbations caused by large impacts and consequences for mantle convection

    E-Print Network [OSTI]

    Watters, W. A.

    We examine the effects of thermal perturbations on a convecting layer of incompressible fluid with uniform viscosity in the limit of infinite Prandtl number, for two upper boundary conditions (free- and no-slip) and heat ...

  4. Study of formation and convective transport of aerosols using optical diagnostic technique

    E-Print Network [OSTI]

    Kim, Tae-Kyun

    2004-09-30T23:59:59.000Z

    . Part II investigates the characteristics of convective transport behavior of solid particles in virtual impactor (VI). The objective of part I is to establish correlations which offer predictions on atomized particle size of HTFs which are widely...

  5. Convective cloud and rainfall processes over the Maritime Continent : simulation and analysis of the diurnal cycle

    E-Print Network [OSTI]

    Gianotti, Rebecca L. (Rebecca Louise)

    2013-01-01T23:59:59.000Z

    The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global ...

  6. Turbulent convection in the anelastic rotating sphere : a model for the circulation on the giant planets

    E-Print Network [OSTI]

    Kaspi, Yohai

    2008-01-01T23:59:59.000Z

    This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, ...

  7. The excitation of solar-like oscillations in a delta Scuti star by efficient envelope convection

    E-Print Network [OSTI]

    Antoci, V; Campante, T L; Thygesen, A O; Moya, A; Kallinger, T; Stello, D; GrigahcŤne, A; Kjeldsen, H; Bedding, T R; LŁftinger, T; Christensen-Dalsgaard, J; Catanzaro, G; Frasca, A; De Cat, P; Uytterhoeven, K; Bruntt, H; Houdek, G; Kurtz, D W; Lenz, P; Kaiser, A; Van Cleve, J; Allen, C; Clarke, B D

    2011-01-01T23:59:59.000Z

    Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses of 1.5-2.5M$_{\\odot}$, their pulsations resulting from the varying ionization of helium. In less massive stars such as the Sun, convection transports mass and energy through the outer 30 per cent of the star and excites a rich spectrum of resonant acoustic modes. Based on the solar example, with no firm theoretical basis, models predict that the convective envelope in delta Sct stars extends only about 1 per cent of the radius, but with sufficient energy to excite solar-like oscillations. This was not observed before the Kepler mission, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the delta Sct star HD 187547, implying that surface convection operates efficiently in stars about twice as massive as the Sun, as the ad hoc models predicted.

  8. Urban Aerosol Impacts on Downwind Convective Storms SUSAN C. VAN DEN HEEVER AND WILLIAM R. COTTON

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

    Urban Aerosol Impacts on Downwind Convective Storms SUSAN C. VAN DEN HEEVER AND WILLIAM R. COTTON. 2004; Givati and Rosenfeld 2004; Molders and Olson 2004; Jirak and Cotton 2006); 2) increased surface

  9. STUDY OF MHD MIXED CONVECTION IN THE DCLL BLANKET SMOLENTSEV Sergey1

    E-Print Network [OSTI]

    Abdou, Mohamed

    , and ABDOU Mohamed3 1 University of California, Los Angeles, USA, sergey@fusion.ucla.edu 2 Laboratoire SIMAP, abdou@fusion.ucla.edu Abstract: Magnetohydrodynamic mixed convection associated with a non

  10. Climate mitigation and the future of tropical landscapes

    SciTech Connect (OSTI)

    Thomson, Allison M.; Calvin, Katherine V.; Chini, Louise Parsons; Hurtt, George; Edmonds, James A.; Bond-Lamberty, Benjamin; Frolking, Steve; Wise, Marshall A.; Janetos, Anthony C.

    2010-11-16T23:59:59.000Z

    Land use change to meet 21st Century demands for food, fuel, and fiber will occur in the context of both a changing climate as well as societal efforts to mitigate climate change. This changing natural and human environment will have large consequences for forest resources, terrestrial carbon storage and emissions, and food and energy crop production over the next century. Any climate change mitigation policies enacted will change the environment under which land-use decisions are made and alter global land use change patterns. Here we use the GCAM integrated assessment model to explore how climate mitigation policies that achieve a climate stabilization at 4.5 W m-2 radiative forcing in 2100 and value carbon in terrestrial ecosystems interact with future agricultural productivity and food and energy demands to influence land use in the tropics. The regional land use results are downscaled from GCAM regions to produce gridded maps of tropical land use change. We find that tropical forests are preserved only in cases where a climate mitigation policy that values terrestrial carbon is in place, and crop productivity growth continues throughout the century. Crop productivity growth is also necessary to avoid large scale deforestation globally and enable the production of bioenergy crops. The terrestrial carbon pricing assumptions in GCAM are effective at avoiding deforestation even when cropland must expand to meet future food demand.

  11. A study of the relationship between certain moisture parameters and severe convective storms in central Oklahoma

    E-Print Network [OSTI]

    Scott, Carven Allen

    2012-06-07T23:59:59.000Z

    A STUDY OF THE RELATIONSHIP BETWEEN CERTAIN MOISTURE PARAMETERS AND SEVERE CONVECTIVE STORMS IN CENTRAL OKLAHOMA A Thesis by CARVEN ALLEN SCOTT Submitted to the Graduate College of Texas ASM University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1977 Major Subject: Meteorology A STUDY OF THE RELATIONSHIP BETWEEN CERTAIN MOISTURE PARAMETERS AND SEVERE CONVECTIVE STORMS IN CENTRAL OKLAHOMA A Thesis by CARVEN ALLEN SCOTT Approved as to style...

  12. P 3.2 OBJECTIVE ENVIRONMENTAL ANALYSES AND CONVECTIVE MODES FOR U.S. TROPICAL CYCLONE TORNADOES FROM 2003-2008

    E-Print Network [OSTI]

    FROM 2003-2008 Roger Edwards 1 , Andrew R. Dean, Richard L. Thompson and Bryan T. Smith Storm Prediction Center, Norman, OK 1 Corresponding author address: Roger Edwards, Storm Prediction Center, National Weather Center, 120 Boren Blvd #2300, Norman, OK 73072; E-mail: roger.edwards@noaa.gov 1

  13. Effects of Radiative Diffusion on Thin Flux Tubes in Turbulent Solar-like Convection

    E-Print Network [OSTI]

    Weber, Maria A

    2015-01-01T23:59:59.000Z

    We study the combined effects of convection and radiative diffusion on the evolution of thin magnetic flux tubes in the solar interior. Radiative diffusion is the primary supplier of heat to convective motions in the lower convection zone, and it results in a heat input per unit volume of magnetic flux tubes that has been ignored by many previous thin flux tube studies. We use a thin flux tube model subject to convection taken from a rotating spherical shell of turbulent, solar-like convection as described by Weber, Fan, and Miesch (2011, Astrophys. J., 741, 11; 2013, Solar Phys., 287, 239), now taking into account the influence of radiative heating on flux tubes of large-scale active regions. Our simulations show that flux tubes of less than or equal to 60 kG subject to solar-like convective flows do not anchor in the overshoot region, but rather drift upward due to the increased buoyancy of the flux tube earlier in its evolution as a result of the inclusion of radiative diffusion. Flux tubes of magnetic fie...

  14. Universidade de Braslia Faculdade de Medicina Programa de Ps-Graduao em Medicina Tropical

    E-Print Network [OSTI]

    Maier, Rudolf Richard

    Universidade de Bras√≠lia ¬≠ Faculdade de Medicina Programa de P√≥s-Gradua√ß√£o em Medicina Tropical Edital n o . 1/2012 1 PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL EDITAL No. 01/2012 SELE√?√?O DE CANDIDATOS √?S VAGAS DO PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL PARA OS CURSOS DE MESTRADO ACAD√?MICO E

  15. UNIVERSIDADE DE BRASLIA PROGRAMA DE PS-GRADUAO EM MEDICINA TROPICAL

    E-Print Network [OSTI]

    Maier, Rudolf Richard

    UNIVERSIDADE DE BRAS√ćLIA PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL EDITAL No. 02/2010 SELE√?√?O DE CANDIDATOS √?S VAGAS DO PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL PARA OS CURSOS DE MESTRADO P√≥s-Gradua√ß√£o em Medicina Tropical, no uso de suas atribui√ß√Ķes legais, torna p√ļblico e estabelece

  16. UNIVERSIDADE DE BRASLIA PROGRAMA DE PS-GRADUAO EM MEDICINA TROPICAL

    E-Print Network [OSTI]

    Maier, Rudolf Richard

    UNIVERSIDADE DE BRAS√ćLIA PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL EDITAL No. 01/2009 SELE√?√?O DE CANDIDATOS √?S VAGAS DO PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL PARA OS CURSOS DE MESTRADO INFECCIOSAS E PARASIT√ĀRIAS 1. PRE√?MBULO 1.1 O Coordenador do Programa de P√≥s-Gradua√ß√£o em Medicina Tropical

  17. UNIVERSIDADE DE BRASLIA PROGRAMA DE PS-GRADUAO EM MEDICINA TROPICAL

    E-Print Network [OSTI]

    Lucero, Jorge Carlos

    UNIVERSIDADE DE BRAS√ćLIA PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL EDITAL No. 03/2011 SELE√?√?O DE CANDIDATOS √?S VAGAS DO PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL PARA OS CURSOS DE MESTRADO Gradua√ß√£o em Medicina Tropical, no uso de suas atribui√ß√Ķes legais, torna p√ļblico e estabelece a retifica√ß√£o

  18. UNIVERSIDADE DE BRASLIA PROGRAMA DE PS-GRADUAO EM MEDICINA TROPICAL

    E-Print Network [OSTI]

    Lucero, Jorge Carlos

    1 UNIVERSIDADE DE BRAS√ćLIA PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL EDITAL No. 02/2011 SELE√?√?O DE CANDIDATOS √?S VAGAS DO PROGRAMA DE P√?S-GRADUA√?√?O EM MEDICINA TROPICAL PARA OS CURSOS DE de P√≥s Gradua√ß√£o em Medicina Tropical, no uso de suas atribui√ß√Ķes legais, torna p√ļblico e estabelece

  19. Materials at the Mesoscale

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recovery challenge fund LasDubey selectedContract ResearchMaterials andMaterials

  20. Closing the Mesoscale Gap

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationClean Communities of WesternVailCloistered JuneLabClosest TypeClosing

  1. Radial convection of finite ion temperature, high amplitude plasma blobs

    SciTech Connect (OSTI)

    Wiesenberger, M., E-mail: Matthias.Wiesenberger@uibk.ac.at; Kendl, A. [Institute for Ion Physics and Applied Physics, Association EURATOM-÷AW, University of Innsbruck, A-6020 Innsbruck (Austria); Madsen, J. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

    2014-09-15T23:59:59.000Z

    We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.

  2. Convective Heating of the LIFE Engine Target During Injection

    SciTech Connect (OSTI)

    Holdener, D S; Tillack, M S; Wang, X R

    2011-10-24T23:59:59.000Z

    Target survival in the hostile, high temperature xenon environment of the proposed Laser Inertial Fusion Energy (LIFE) engine is critical. This work focuses on the flow properties and convective heat load imposed upon the surface of the indirect drive target while traveling through the xenon gas. While this rarefied flow is traditionally characterized as being within the continuum regime, it is approaching transition where conventional CFD codes reach their bounds of operation. Thus ANSYS, specifically the Navier-Stokes module CFX, will be used in parallel with direct simulation Monte Carlo code DS2V and analytically and empirically derived expressions for heat transfer to the hohlraum for validation. Comparison of the viscous and thermal boundary layers of ANSYS and DS2V were shown to be nearly identical, with the surface heat flux varying less than 8% on average. From the results herein, external baffles have been shown to reduce this heat transfer to the sensitive laser entrance hole (LEH) windows and optimize target survival independent of other reactor parameters.

  3. E-Print Network 3.0 - australian tropical rainforest Sample Search...

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

    RAINFORESTS OF ... Source: James Cook University, Centre for Tropical Biodiversity and Climate Change Collection: Environmental Sciences and Ecology ; Biology and Medicine 2...

  4. E-Print Network 3.0 - australian wet tropics Sample Search Results

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

    OF THE WET ... Source: James Cook University, Centre for Tropical Biodiversity and Climate Change Collection: Environmental Sciences and Ecology ; Biology and Medicine 3...

  5. Deep Signatures of Southern Tropical Indian Ocean Annual Rossby Waves* GREGORY C. JOHNSON

    E-Print Network [OSTI]

    Johnson, Gregory C.

    Deep Signatures of Southern Tropical Indian Ocean Annual Rossby Waves* GREGORY C. JOHNSON NOAA Environmental Laboratory Contribution Number 3671. Corresponding author address: Gregory C. Johnson, NOAA

  6. Atmospheric Dispersion at Spatial Resolutions Below Mesoscale for university of Tennessee SimCenter at Chattanooga: Final Report

    SciTech Connect (OSTI)

    Dr. David Whitfield; Dr. Daniel Hyams

    2009-09-14T23:59:59.000Z

    In Year 1 of this project, items 1.1 and 1.2 were addressed, as well as item 2.2. The baseline parallel computational simulation tool has been refined significantly over the timeline of this project for the purpose of atmospheric dispersion and transport problems; some of these refinements are documented in Chapter 3. The addition of a concentration transport capability (item 1.2) was completed, along with validation and usage in a highly complex urban environment. Multigrid capability (item 2.2) was a primary focus of Year 1 as well, regardless of the fact that it was scheduled for Year 2. It was determined by the authors that due to the very large nature of the meshes required for atmospheric simulations at mesoscale, multigrid was a key enabling technology for the rest of the project to be successful. Therefore, it was addressed early according to the schedule laid out in the original proposal. The technology behind the multigrid capability is discussed in detail in Chapter 5. Also in Year 1, the issue of ground topography specification is addressed. For simulations of pollutant transport in a given region, a key prerequisite is the specification of the detailed ground topography. The local topography must be placed into a form suitable for generating an unstructured grid both on the topography itself and the atmospheric volume above it; this effort is documented in Chapter 6. In Year 2 of this project, items 1.3 and 2.1 were addressed. Weather data in the form of wind speeds, relative humidity, and baseline pollution levels may be input into the code in order to improve the real-world fidelity of the solutions. Of course, the computational atmospheric boundary layer (ABL) boundary condition developed in Year 1 may still be used when necessary. Cloud cover may be simulated via the levels of actinic flux allowed in photochemical reactions in the atmospheric chemistry model. The primary focus of Year 2 was the formulation of a multispecies capability with included chemical reactions (item 2.1). This proved to be a very arduous task, taking the vast majority of the time and personnel allocation for Year Two. The addition of this capability and related verification is documented in Chapter 7. A discussion of available tropospheric chemistry models is located in Chapter 8; and, a technology demonstrator for the full multispecies capability is detailed in Chapter 9. Item 2.3 has been partially addressed, in that the computation of sensitivity derivatives have been incorporated in the Tenasi code [7]. However, it has not been utilized in this project in order to compute probability distribution functions for pollutant deposition. In order to completely address the integration of weather and sensor data into the code (item 1.3) and integrate with existing sensor networks (item 3.1), a customizable interface was established. Weather data is most commonly available via a real database, and as such, support for accessing these databases is present in the solver source code. For integration functionality, a method of dynamic code customization was developed in Year 3, which is documented in Chapter 11.

  7. Impact of Pacific and Atlantic sea surface temperatures on interannual and decadal variations of GRACE land water storage in tropical South America

    E-Print Network [OSTI]

    de Linage, Caroline; Kim, Hyungjun; Famiglietti, James S; Yu, Jin-Yi

    2013-01-01T23:59:59.000Z

    re season severity in South America using sea surface tem-storage in tropical South America, J. Geophys. Res. Atmos. ,hydroclimatology of tropical South America is characterized

  8. Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation

    SciTech Connect (OSTI)

    Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)

    2014-08-15T23:59:59.000Z

    A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudyĖclear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.

  9. The Influence of El Nin~oSouthern Oscillation and the Atlantic Multidecadal Oscillation on Caribbean Tropical Cyclone Activity

    E-Print Network [OSTI]

    Gray, William

    on Caribbean Tropical Cyclone Activity PHILIP J. KLOTZBACH Department of Atmospheric Science, Colorado State Caribbean basin tropical cyclone activity shows significant variability on interannual as well as multidecadal time scales. Comprehensive statistics for Caribbean hurricane activity are tabulated

  10. The occurrence and diversity of tree legumes as influenced by soil properties in selected tropical forests in Costa Rica

    E-Print Network [OSTI]

    Wesch, Richard Albert

    1999-01-01T23:59:59.000Z

    Legumes play important roles in tropical forests due to their contribution to N?-fixation and nutrient cycling. Our objectives were to determine which soil properties, if any, affect the occurrence and distribution of tree legumes in a tropical wet...

  11. Anvil characteristics as seen by C-POL during the Tropical Warm Pool International Cloud Experiment (TWP-ICE)

    E-Print Network [OSTI]

    Frederick, Kaycee Loretta

    2007-04-25T23:59:59.000Z

    The Tropical Pacific Warm Pool International Cloud Experiment (TWP-ICE) took place in Darwin, Australia in early 2006. C-band radar data from this experiment were used to characterize tropical anvil areal coverage, height, and thickness during...

  12. Tropical Africa: Land use, biomass, and carbon estimates for 1980

    SciTech Connect (OSTI)

    Brown, S. [Environmental Protection Agency, Corvallis, OR (United States). Western Ecology Division; Gaston, G. [Environmental Protection Agency, Corvallis, OR (United States). National Research Council; Daniels, R.C. [ed.] [Oak Ridge National Lab., TN (United States)

    1996-06-01T23:59:59.000Z

    This document describes the contents of a digital database containing maximum potential aboveground biomass, land use, and estimated biomass and carbon data for 1980 and describes a methodology that may be used to extend this data set to 1990 and beyond based on population and land cover data. The biomass data and carbon estimates are for woody vegetation in Tropical Africa. These data were collected to reduce the uncertainty associated with the possible magnitude of historical releases of carbon from land use change. Tropical Africa is defined here as encompassing 22.7 x 10{sup 6} km{sup 2} of the earth`s land surface and includes those countries that for the most part are located in Tropical Africa. Countries bordering the Mediterranean Sea and in southern Africa (i.e., Egypt, Libya, Tunisia, Algeria, Morocco, South Africa, Lesotho, Swaziland, and Western Sahara) have maximum potential biomass and land cover information but do not have biomass or carbon estimate. The database was developed using the GRID module in the ARC/INFO{sup TM} geographic information system. Source data were obtained from the Food and Agriculture Organization (FAO), the U.S. National Geophysical Data Center, and a limited number of biomass-carbon density case studies. These data were used to derive the maximum potential and actual (ca. 1980) aboveground biomass-carbon values at regional and country levels. The land-use data provided were derived from a vegetation map originally produced for the FAO by the International Institute of Vegetation Mapping, Toulouse, France.

  13. Tropical air mass modification over water (Gulf of Mexico Region)

    E-Print Network [OSTI]

    Sorgnit, Ernest Frederick

    1952-01-01T23:59:59.000Z

    . Scripps Institution of Oceanography, Oceanographic Report No. 9 (Fog Pro)sot) Lopes, M. E. 194S A technique for detailed radiosonde analysis in the tropics. Bull. Amer. Meteor. Soc. , Vol. 29, No. 5. Solot, S. R. 1939 Computations of' depth... represents an aporoxi- mate equilibrium with respect to the surface beneath. Thus, an air mass may be identified by the vertical structure it acquires over a source Willett, H. D. , Papers in Phys. Ocn. and Met. , Vol. II, No. 2, 1943 region. The concept...

  14. A Model Evaluation Data Set for the Tropical ARM Sites

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

    Jakob, Christian

    This data set has been derived from various ARM and external data sources with the main aim of providing modelers easy access to quality controlled data for model evaluation. The data set contains highly aggregated (in time) data from a number of sources at the tropical ARM sites at Manus and Nauru. It spans the years of 1999 and 2000. The data set contains information on downward surface radiation; surface meteorology, including precipitation; atmospheric water vapor and cloud liquid water content; hydrometeor cover as a function of height; and cloud cover, cloud optical thickness and cloud top pressure information provided by the International Satellite Cloud Climatology Project (ISCCP).

  15. Rapid transport of East Asian pollution to the deep tropics

    E-Print Network [OSTI]

    Ashfold, M. J.; Pyle, J. A.; Robinson, A. D.; Nadzir, M. S. M.; Phang, S. M.; Samah, A. A.; Ong, S.; Ung, H. E.; Peng, L. K.; Yong, S. E.; Harris, N. R. P.

    2014-12-05T23:59:59.000Z

    , and biomass burning in tropical continental Southeast Asia: observations in rural Thai- land, J. Geophys. Res.-Atmos., 108, 4552, doi:10.1029/2002JD003360, 2003. 30708 Pyle, J. A., Ashfold, M. J., Harris, N. R. P., Robinson, A. D., Warwick, N. J., Carver, G. D... mid-latitudes rapidly to equatorial Southeast Asia.15 4 Wider air quality implications Thus far we have focussed on C2Cl4, an industrial pollutant observed in relatively small quantities. It is clearly of interest to consider how this pollution...

  16. The Tropical Warm Pool International Cloud Experiment: Overview

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2 andThe MolecularPlaceThe AnTheforThe Tropical Warm

  17. Are tropical fungal endophytes hyperdiverse? Fungal endophytes are ubiquitous fungi that inhabit healthy plant tissues without

    E-Print Network [OSTI]

    California at Berkeley, University of

    Are tropical fungal endophytes hyperdiverse? Abstract Fungal endophytes are ubiquitous fungi that inhabit healthy plant tissues without causing disease. Endophytes have been found in every plant species sites in a lowland, moist tropical forest of central Panama, we quantified endophyte colonization

  18. Thermodynamics of tropical cyclogenesis in the northwest Pacific D. J. Raymond,1

    E-Print Network [OSTI]

    Raymond, David J.

    Thermodynamics of tropical cyclogenesis in the northwest Pacific D. J. Raymond,1 S. L. Sessions,1 and thermodynamic products were derived from dropsonde and airborne Doppler radar data, with the goal of increasing: Raymond, D. J., S. L. Sessions, and C. Lůpez Carrillo (2011), Thermodynamics of tropical cyclogenesis

  19. Intermediate Zonal Jets in the Tropical Pacific Ocean Observed by Argo Floats* SOPHIE CRAVATTE

    E-Print Network [OSTI]

    Boyer, Edmond

    Intermediate Zonal Jets in the Tropical Pacific Ocean Observed by Argo Floats* SOPHIE CRAVATTE¬īveloppement, LEGOS, Toulouse, France WILLIAM S. KESSLER National Oceanic and Atmospheric Administration/Pacific Argo float data in the tropical Pacific Ocean during January 2003¬≠August 2011 are analyzed to obtain

  20. Shipboard Measurements and Estimations of AirSea Fluxes in the Western Tropical Pacific Ocean

    E-Print Network [OSTI]

    California at Irvine, University of

    Ship­board Measurements and Estimations of Air­Sea Fluxes in the Western Tropical Pacific Ocean E dur­ ing the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean and Atmospheric Response of the surface­layer turbulence properties are compared with those from previous land and ocean results. Momentum

  1. Microphysical and radiative evolution of aerosol plumes over the tropical North Atlantic Ocean

    E-Print Network [OSTI]

    Russell, Lynn

    Microphysical and radiative evolution of aerosol plumes over the tropical North Atlantic Ocean] Over the tropical North Atlantic Ocean in the summer, plumes of aerosol extend from Saharan Africa to the Caribbean. The microphysical and radiative evolution of such plumes is studied using a Lagrangian column

  2. Relative timing of last glacial maximum and late-glacial events in the central tropical Andes

    E-Print Network [OSTI]

    Winckler, Gisela

    , and CO2. Moreover, as the energetic powerhouse of the earth, the tropics have huge potential to trigger shifts in tropical temperature and precipitation during the Late Pleistocene (ice-core data: Thompson et al., 1995, 1998; lake-core data: Baker et al., 2001a, b; glacial-geologic data: Smith et al., 2005a

  3. SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS

    E-Print Network [OSTI]

    Hennon, Christopher C.

    SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS--Scatterometer measurements of ocean vector winds (OVW) are significantly degraded in the presence of the precipitation, especially in tropical cyclones. This paper presents a new ocean hurricane/typhoon wind vector retrieval

  4. Isentropic Slopes, Downgradient Eddy Fluxes, and the Extratropical Atmospheric Circulation Response to Tropical Tropospheric Heating

    E-Print Network [OSTI]

    to Tropical Tropospheric Heating AMY H. BUTLER NOAA/NWS/NCEP/Climate Prediction Center, Camp Springs, Maryland of the midlatitude jets and their associated eddy fluxes of heat and potential vorticity (PV). Experiments run latent heating and thus locally enhanced warming in the tropical troposphere. Here the authors provide

  5. Do Gravity Waves Transport Angular Momentum away from Tropical Cyclones? YUMIN MOON AND DAVID S. NOLAN

    E-Print Network [OSTI]

    Nolan, David S.

    Do Gravity Waves Transport Angular Momentum away from Tropical Cyclones? YUMIN MOON AND DAVID S that gravity waves can transport a significantly large amount of angular momentum away from tropical cyclones-water equations to model gravity waves radiating outward from rapidly rotating inner-core asymmetries. This issue

  6. THE EXTENT AND CAUSES OF ILLEGAL LOGGING: AN ANALYSIS OF A MAJOR CAUSE OF TROPICAL

    E-Print Network [OSTI]

    THE EXTENT AND CAUSES OF ILLEGAL LOGGING: AN ANALYSIS OF A MAJOR CAUSE OF TROPICAL DEFORESTATION;2 THE EXTENT AND CAUSES OF ILLEGAL LOGGING: AN ANALYSIS OF A MAJOR CAUSE OF TROPICAL DEFORESTATION IN INDONESIA high rates of deforestation in Indonesia. Its extent during 1997-98 is analysed using a materials

  7. Characterizing a tropical deforestation wave: a dynamic spatial analysis of a deforestation hotspot in the

    E-Print Network [OSTI]

    Queensland, University of

    Characterizing a tropical deforestation wave: a dynamic spatial analysis of a deforestation hotspot deforestation is the major contemporary threat to global biodiversity, because a diminishing extent of tropical of deforestation. How- ever, it is not a random process, but often moves in waves originating from settled areas

  8. Energy dynamics and modeled evapotranspiration from a wet tropical forest in Costa Rica

    E-Print Network [OSTI]

    Energy dynamics and modeled evapotranspiration from a wet tropical forest in Costa Rica H). #12;1. Introduction The energy balance of tropical forests is complex due to feedback mechanisms among.W. Loeschera, *, H.L. Gholza,b , J.M. Jacobsc , S.F. Oberbauerd,e a School of Forest Resources and Conservation

  9. Presentation 2.6: Wood waste for energy: lessons learnt from tropical regions Paul Vantomme

    E-Print Network [OSTI]

    of forest products with more value adding, and promoting the use of wood waste to increase energy efficiency tropical timber trade · almost 80% of the world's tropical forests ITTO ­ Wood Waste for Energy Working and forest industries GhanaDevelopment of energy alternatives for the efficient utilization of wood

  10. Large CO2 disequilibria in tropical lakes Humberto Marotta,1,2

    E-Print Network [OSTI]

    Wehrli, Bernhard

    Large CO2 disequilibria in tropical lakes Humberto Marotta,1,2 Carlos M. Duarte,2 Sebastian Sobek,3 November 2009. [1] On the basis of a broad compilation of data on pCO2 in surface waters, we show tropical lakes to be, on average, far more supersaturated and variable in CO2 (geometric mean ¬Ī SE pCO2 = 1804

  11. VARIABILITY OF FREE TROPOSPHERIC HUMIDITY FROM METEOSAT OVER THE TROPICS: 1983-2005

    E-Print Network [OSTI]

    Brogniez, Hélène

    1 , Julien Lémond 2 , Rémy Roca 2 and Laurence Picon 2 1 Centre d'Etude des Environnements Terrestre to the complex mixing of extra tropical and tropical air that modulates the dryness of the area. Preliminary

  12. Vertical Structure of Tropical Cyclone Rainbands as Seen by the TRMM Precipitation Radar

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    Vertical Structure of Tropical Cyclone Rainbands as Seen by the TRMM Precipitation Radar DEANNA A Measurement Mission satellite's Precipitation Radar (TRMM PR) show the vertical structure of tropical cyclone separated by the melting layer. The ice layer is a combination of particles imported from the eyewall

  13. Influence of local and remote SST on North Atlantic tropical cyclone potential intensity

    E-Print Network [OSTI]

    Camargo, Suzana J.

    Influence of local and remote SST on North Atlantic tropical cyclone potential intensity Suzana J of local and remote sea surface temperature (SST) on the tropical cyclone potential intensity in the North Atlantic using a suite of model simulations, while separating the impact of anthropogenic (external

  14. The increasing intensity of the strongest tropical James B. Elsner1

    E-Print Network [OSTI]

    Kossin, James P.

    cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the veryLETTERS The increasing intensity of the strongest tropical cyclones James B. Elsner1 , James P. Kossin2 & Thomas H. Jagger1 Atlantic tropical cyclones are getting stronger on average, with a 30-year

  15. Sensitivity of an Ocean-Atmosphere Coupled Model to the Coupling Method : Study of Tropical Cyclone

    E-Print Network [OSTI]

    Recanati, Catherine

    Sensitivity of an Ocean-Atmosphere Coupled Model to the Coupling Method : Study of Tropical Cyclone) in a realistic configuration aiming at simulating the genesis and propagation of tropical cyclone Erica and Oceanic Coupled Models (AOCMs) which account for important air-sea feedbacks. Separate integrations

  16. Tropical Cyclone and Monsoon-Induced Rainfall Variability in Taiwan JAU-MING CHEN

    E-Print Network [OSTI]

    Li, Tim

    Tropical Cyclone≠ and Monsoon-Induced Rainfall Variability in Taiwan JAU-MING CHEN Institute March 2010) ABSTRACT This study investigates the interannual variability of tropical cyclone (TC the relative effects of TCs and monsoons, local rainfall in Taiwan is separated into two subcomponents: TC

  17. Modulation of North Pacific Tropical Cyclone Activity by the2 Three Phases of ENSO3

    E-Print Network [OSTI]

    Webster, Peter J.

    1 1 Modulation of North Pacific Tropical Cyclone Activity by the2 Three Phases of ENSO3 4 Hye-Mail: hyemi.kim@eas.gatech.edu29 30 #12;2 Abstract30 Pacific Ocean warming has been separated into two modes (EPC), these three regimes are shown to have different impacts on34 tropical cyclone activity over

  18. Use of a Genesis Potential Index to Diagnose ENSO Effects on Tropical Cyclone Genesis

    E-Print Network [OSTI]

    Sobel, Adam

    Use of a Genesis Potential Index to Diagnose ENSO Effects on Tropical Cyclone Genesis SUZANA J influence on tropical cyclone activity. The authors examine how different environmental factors contribute. Composite anomalies of the genesis potential index are produced for El NiŮo and La NiŮa years separately

  19. Sensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone

    E-Print Network [OSTI]

    Sensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone and propagation of tropical cyclone Erica. Sensitiv- ity tests to the coupling method are carried out-sea feedbacks. Separate integrations of the Corresponding author. Phone: +33 (0)4 76 51 48 60 Fax: +33 (0)4 76

  20. Vertical Structure of Tropical Cyclone Rainbands as seen by the TRMM Precipitation Radar

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    1 Vertical Structure of Tropical Cyclone Rainbands as seen by the TRMM Precipitation Radar Deanna A (TRMM PR) show the vertical structure of tropical cyclone rainbands. Radar-echo2 statistics show that rainbands have a two-layered structure, with distinct modes separated by the3 melting layer. The ice layer