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Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Relating Cirrus Cloud Properties to Observed Fluxes: A Critical Assessment  

Science Conference Proceedings (OSTI)

The accuracy needed in cirrus cloud scattering and microphysical properties is quantified such that the radiative effect on climate can he determined. Our ability to compute and observe these properties to within needed accuracies is assessed, ...

A. M. Vogelmann; T. P. Ackerman

1995-12-01T23:59:59.000Z

2

A Cirrus-Cloud Experiment: Intensive Field Observations Planned for Fire  

Science Conference Proceedings (OSTI)

Plans for an intensive cirrus-cloud field experiment are described. The Cirrus Intensive Field Observations (Citrus IFO) is a major component of the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE). The ...

David O'C. Starr

1987-02-01T23:59:59.000Z

3

Cirrus Cloud Properties from a Cloud-Resolving Model Simulation Compared to Cloud Radar Observations  

Science Conference Proceedings (OSTI)

Cloud radar data collected at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains site were used to evaluate the properties of cirrus clouds that occurred in a cloud-resolving model (CRM) simulation of the 29-day summer ...

Yali Luo; Steven K. Krueger; Gerald G. Mace; Kuan-Man Xu

2003-02-01T23:59:59.000Z

4

In Situ Observations of the Microphysical Properties of Wave, Cirrus, and Anvil Clouds. Part II: Cirrus Clouds  

Science Conference Proceedings (OSTI)

A Learjet research aircraft was used to collect microphysical data, including cloud particle imager (CPI) measurements of ice particle size and shape, in 22 midlatitude cirrus clouds. The dataset was collected while the aircraft flew 104 ...

R. Paul Lawson; Brad Baker; Bryan Pilson; Qixu Mo

2006-12-01T23:59:59.000Z

5

In Situ Observations of Cirrus Cloud Microphysical Properties Using the Counterflow Virtual Impactor  

Science Conference Proceedings (OSTI)

This study presents a new technique for making in situ measurements of cirrus cloud microphysical properties. Sampling of cirrus clouds was performed using a counterflow virtual impactor (CVI). The CVI was used to sample cloud elements larger ...

K. B. Noone; K. J. Noone; J. Heintzenberg; J. Ström; J. A. Ogren

1993-06-01T23:59:59.000Z

6

Dynamical Characteristics of Cirrus Clouds from Aircraft and Radar Observations in Micro and Meso-? Scales  

Science Conference Proceedings (OSTI)

Cirrus clouds that formed on 26 November and 6 December 1991 during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) II, which took place over the Kansas region. are studied because of significant dynamic ...

I. Gultepe; D. O'C. Starr; A. J. Heymsfield; T. Uttal; T. P. Ackerman; D. L. WestPhal

1995-12-01T23:59:59.000Z

7

Lidar Observation of the Cirrus Cloud in the Tropopause at Chung-Li (25°N, 121°E)  

Science Conference Proceedings (OSTI)

The authors have detected a cirrus cloud near the tropopause by using a lidar system located at Chung-Li, Taiwan (25°N, 121°E). The cloud usually appeared between the month of May and September. In 1993–95, the cloud was observed almost 50% of ...

J. B. Nee; C. N. Len; W. N. Chen; C. I. Lin

1998-06-01T23:59:59.000Z

8

Cirrus Cloud Radiative and Microphysical Properties from Ground Observations and In Situ Measurements during FIRE 1991 and Their Application to Exhibit Problems in Cirrus Solar Radiative Transfer Modeling  

Science Conference Proceedings (OSTI)

Measurements from the FIRE 1991 cirrus cloud field experiment in the central United States are presented and analyzed.

S. Kinne; T. P. Ackerman; M. Shiobara; A. Uchiyama; A. J. Heymsfield; L. Miloshevich; J. Wendell; E. Eloranta; C. Purgold; R. W. Bergstrom

1997-09-01T23:59:59.000Z

9

Testing a New Cirrus Cloud Parameterizaton  

NLE Websites -- All DOE Office Websites (Extended Search)

Testing a New Cirrus Cloud Parameterization Testing a New Cirrus Cloud Parameterization in NCAR CCM3 D. Zurovac-Jevtic, G. J. Zhang, and V. Ramanathan Center for Atmospheric Sciences Scripps Institute of Oceanography La Jolla, California Introduction Cirrus cloud cover and ice water content (IWC) are the two most important properties of cirrus clouds. However, in general circulation models (GCMs), their treatment is very crude. For example, in the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3), IWC is prescribed as a function of column-integrated water vapor and height (Hack 1998). The in situ observations in the tropics indicate that the cirrus IWC is an order of magnitude larger than what is prescribed in the model (McFarquhar and Heymsfield 1996). The comparison with the International

10

Observed and Simulated Cirrus Cloud Properties at the SGP CART Site  

NLE Websites -- All DOE Office Websites (Extended Search)

and Simulated Cirrus Cloud Properties and Simulated Cirrus Cloud Properties at the SGP CART Site A. D. Del Genio and A. B. Wolf National Aeronautics and Space Administration Goddard Institute for Space Studies New York, New York G. G. Mace University of Utah Salt Lake City, Utah Introduction Despite their potential importance in a long-term climate change, less is known about cirrus clouds than most other cloud types, for a variety of reasons (Del Genio 2001) including: (1) the difficulty of remotely sensing ice water content (IWC), (2) uncertainty in the identities of ice nuclei and the relative importance of different nucleation processes, (3) significant variations in depth and optical thickness caused by formation and sedimentation of large particles, and (4) our relatively poor documentation of

11

Analysis of Aircraft, Radiosonde, and Radar Observations in Cirrus Clouds Observed during FIRE II: The Interactions between Environmental Structure, Turbulence, and Cloud Microphysical Properties  

Science Conference Proceedings (OSTI)

Ways to determine the turbulence intensity and the horizontal variability in cirrus clouds have been investigated using First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment II aircraft, radiosonde, and radar data. ...

Samantha A. Smith; Anthony D. DelGenio

2001-03-01T23:59:59.000Z

12

Relative Humidity and Temperature Influences on Cirrus Formation and Evolution: Observations from Wave Clouds and FIRE II  

Science Conference Proceedings (OSTI)

Measurements in orographic wave clouds. and in cirrus sampled during FIRE II, are used to investigate ice nucleation in the upper troposphere. The dynamically and microphysically simpler quasi-steady-state wave clouds provide relatively ideal ...

Andrew J. Heymsfield; Larry M. Miloshevich

1995-12-01T23:59:59.000Z

13

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

E-Print Network (OSTI)

This dissertation focuses on the global investigation of optically thin cirrus cloud optical thickness (tau) and microphysical properties, such as, effective particle size (D_(eff)) and ice crystal habits (shapes), based on the global satellite observations and fast radiative transfer models (RTMs). In the first part, we develop two computationally efficient RTMs simulating satellite observations under cloudy-sky conditions in the visible/shortwave infrared (VIS/SWIR) and thermal inferred (IR) spectral regions, respectively. To mitigate the computational burden associated with absorption, thermal emission and multiple scattering, we generate pre-computed lookup tables (LUTs) using two rigorous models, i.e., the line-by-line radiative transfer model (LBLRTM) and the discrete ordinates radiative transfer model (DISORT). The second part introduces two methods (i.e., VIS/SWIR- and IR-based methods) to retrieve tau and D_(eff) from satellite observations in corresponding spectral regions of the two RTMs. We discuss the advantages and weakness of the two methods by estimating the impacts from different error sources on the retrievals through sensitivity studies. Finally, we develop a new method to infer the scattering phase functions of optically thin cirrus clouds in a water vapor absorption channel (1.38-µm). We estimate the ice crystal habits and surface structures by comparing the inferred scattering phase functions and numerically simulated phase functions calculated using idealized habits.

Wang, Chenxi

2013-08-01T23:59:59.000Z

14

Radiative Properties of Cirrus Clouds Derived from Surface Interferometric Measurements  

Science Conference Proceedings (OSTI)

Beam transmittance, emittance, reflectance, and outgoing radiance are inferred from interferometric measurements in the infrared window region for 14 temperate continental and 12 subtropical cirrus cloud cash observed during FIRE II at Parsons, ...

Gordon H. Beck; John M. Davis; S. K. Cox

1996-08-01T23:59:59.000Z

15

On the Transition of Contrails into Cirrus Clouds  

Science Conference Proceedings (OSTI)

In situ observations of the microphysical properties of upper-tropospheric contrails and cirrus clouds have been performed during more than 15 airborne missions over central Europe. Experimental and technical aspects concerning in situ ...

F. Schröder; B. Kärcher; C. Duroure; J. Ström; A. Petzold; J.-F. Gayet; B. Strauss; P. Wendling; S. Borrmann

2000-02-01T23:59:59.000Z

16

Simulations of cirrus clouds using an explicit cloud model: integrating ARM  

NLE Websites -- All DOE Office Websites (Extended Search)

Simulations of cirrus clouds using an explicit cloud model: integrating ARM Simulations of cirrus clouds using an explicit cloud model: integrating ARM water vapor and forcing data for analysis of cirrus formation and evolution Comstock, Jennifer Pacific Northwest National Laboratory Lin, Ruei-Fong NASA/Goddard Space Flight Center Starr, David NASA/Goddard Space Flight Center Yang, Ping Texas A&M Category: Modeling Understanding the atmospheric conditions required to initiate cirrus formation and produce observed microphysical properties is crucial to improving the representation of cirrus clouds in climate models. Ice formation in cirrus generally occurs at cold temperatures (below -30 ď‚°C) and can take the form of either homogeneous or heterogeneous nucleation. The ice supersaturation required for ice formation is smaller for

17

LIRAD Observations of Tropical Cirrus Clouds in MCTEX. Part II: Optical Properties and Base Cooling in Dissipating Storm Anvil Clouds  

Science Conference Proceedings (OSTI)

During the Maritime Continent Thunderstorm Experiment (MCTEX), several decaying storm anvils were observed. The anvil clouds exhibited typical patterns of fallout and decay over a number of hours of observation. The anvil bases were initially ...

C. M. R. Platt; R. T. Austin; S. A. Young; A. J. Heymsfield

2002-11-01T23:59:59.000Z

18

Cirrus Clouds and the Large-Scale Atmospheric State: Relationships Revealed by Six Years of Ground-Based Data  

Science Conference Proceedings (OSTI)

The properties of cirrus clouds observed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) in Oklahoma are documented from a nearly continuous 6-yr record of 35-GHz cloud radar data. Cirrus frequency over the ACRF is ...

Gerald G. Mace; Sally Benson; Erik Vernon

2006-07-01T23:59:59.000Z

19

Microphysical and Dynamical Influences on Cirrus Cloud Optical Depth Distributions  

SciTech Connect

Cirrus cloud inhomogeneity occurs at scales greater than the cirrus radiative smoothing scale ({approx}100 m), but less than typical global climate model (GCM) resolutions ({approx}300 km). Therefore, calculating cirrus radiative impacts in GCMs requires an optical depth distribution parameterization. Radiative transfer calculations are sensitive to optical depth distribution assumptions (Fu et al. 2000; Carlin et al. 2002). Using raman lidar observations, we quantify cirrus timescales and optical depth distributions at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Lamont, OK (USA). We demonstrate the sensitivity of outgoing longwave radiation (OLR) calculations to assumed optical depth distributions and to the temporal resolution of optical depth measurements. Recent work has highlighted the importance of dynamics and nucleation for cirrus evolution (Haag and Karcher 2004; Karcher and Strom 2003). We need to understand the main controls on cirrus optical depth distributions to incorporate cirrus variability into model radiative transfer calculations. With an explicit ice microphysics parcel model, we aim to understand the influence of ice nucleation mechanism and imposed dynamics on cirrus optical depth distributions.

Kay, J.; Baker, M.; Hegg, D.

2005-03-18T23:59:59.000Z

20

Mesoscale and Microscale Structure of Cirrus Clouds: Three Case Studies  

Science Conference Proceedings (OSTI)

The structure and composition of three basic cirrus cloud types are examined through coordinated aircraft and ground-based polarization lidar and radar measurements. The cloud systems consist of a multilayered orographic cirrus, a 6-km deep ...

Kenneth Sassen; David O'C. Starr; Taneil Uttal

1989-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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

E-Print Network (OSTI)

supersaturation in mixed-phase clouds is the saturation vapor pressure weighted by the proportions of ice to be in the liquid phase for clouds warmer than -35ÂşC, and is assumed to be in the ice phase for cirrus clouds. The conversion of this detrained condensate from liquid phase into the ice phase in the mixed-phase clouds

Meskhidze, Nicholas

22

Posters Sensitivity of Cirrus Cloud Radiative  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 Posters Sensitivity of Cirrus Cloud Radiative Properties to Ice Crystal Size and Shape in General Circulation Model Simulations D. L. Mitchell Desert Research Institute Reno, Nevada J. E. Kristjánsson Department of Geophysics University of Oslo, Norway M. J. Newman Los Alamos National Laboratory Los Alamos, New Mexico Introduction Recent research (e.g., Mitchell and Arnott 1994) has shown that the radiative properties of cirrus clouds (i.e., optical depth, albedo, emissivity) depend on the shapes and sizes of ice crystals. For instance, the cloud albedo may vary by a factor of two, depending on whether hexagonal columns or bullet rosette ice crystals are assumed for a given ice water path (IWP). This variance occurs primarily because, at sizes characteristic of cirrus

23

In Situ Observations of the Microphysical Properties of Wave, Cirrus, and Anvil Clouds. Part I: Wave Clouds  

Science Conference Proceedings (OSTI)

The microphysical properties of wave clouds based on data collected during 17 missions flown by a Learjet research aircraft are presented and discussed. This extensive dataset expands upon previous aircraft studies of wave clouds and introduces ...

Brad A. Baker; R. Paul Lawson

2006-12-01T23:59:59.000Z

24

The Prospect for Remote Sensing of Cirrus Clouds with a Submillimeter-Wave Spectrometer  

Science Conference Proceedings (OSTI)

Given the substantial radiative effects of cirrus clouds and the need to validate cirrus cloud mass in climate models, it is important to measure the global distribution of cirrus properties with satellite remote sensing. Existing cirrus remote ...

K. Franklin Evans; Aaron H. Evans; Ira G. Nolt; B. Thomas Marshall

1999-05-01T23:59:59.000Z

25

Modeling of Submillimeter Passive Remote Sensing of Cirrus Clouds  

Science Conference Proceedings (OSTI)

The scattering properties of cirrus clouds at submillimeter-wave frequencies are analyzed and characterized in this paper. This study lays a theoretical foundation for using radiometric measurements to investigate and monitor cirrus properties ...

K. Franklin Evans; Steven J. Walter; Andrew J. Heymsfield; Merritt N. Deeter

1998-02-01T23:59:59.000Z

26

Cirrus Clouds. Part I: A Cirrus Cloud Model  

Science Conference Proceedings (OSTI)

A two-dimensional (x, z), time-dependent, numerical cloud model is developed for the purpose of investigating the role of various physical processes involved in the maintenance of cirriform clouds. In addition to accounting for dynamic and ...

David O'C. Starr; Stephen K. Cox

1985-12-01T23:59:59.000Z

27

Four Years of Global Cirrus Cloud Statistics Using HIRS  

Science Conference Proceedings (OSTI)

Trends in global upper-tropospheric transmissive cirrus cloud cover are beginning to emerge from a four-year cloud climatology using NOAA polar-orbiting High-Resolution Infrared Radiation Sounder (HIRS) multispectral data. Cloud occurrence, ...

Donald P. Wylie; W. Paul Menzel; Harold M. Woolf; Kathleen I. Strabala

1994-12-01T23:59:59.000Z

28

Comparison of the CALIPSO satellite and ground-based observations of cirrus clouds at the ARM TWP sites  

SciTech Connect

Statistics of ice cloud macrophysical and optical properties from the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) instrument on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite are compared with those from ground-based lidar observations over a 31 month period. Ground-based lidar observations are taken from the micropulse lidars (MPL) at the three Department of Energy Atmospheric Radiation Measurement (ARM) tropical western pacific (TWP) sites: Manus, Nauru and Darwin. CALIPSO observations show a larger cloud fraction at high altitudes while the ground-based MPLs show a larger cloud fraction at low altitudes. The difference in mean ice cloud top and base heights at the Manus and Nauru sites are all within 0.51 km, although differences are statistically significant. Mean ice cloud geometrical thickness agree to within 0.05 km at the Manus and Nauru sites. Larger differences exist at Darwin due to excessive degradation of the MPL output power during our sampling period. Both sets of observations show thicker clouds during the nighttime which may be real but could also be partially an artifact of the decreased signal-to-noise ratio during the daytime. The number of ice cloud layers per profile are also shown to be consistent after accounting for the difference in spatial resolution. For cloud optical depths, four different retrieval methods are compared, two for each set of observations. All products show that the majority of ice cloud optical depths ({approx}60%) fall below an optical depth of 0.2. For most comparisons all four retrievals agree to within the uncertainty intervals. We find that both CALIPSO retrievals agree best to ground-based optical depths when the lidar ratio in the latter is retrieved instead of set to a fixed value. Also thoroughly compared is the cloud properties for the subset of ice clouds which reside in the tropical tropopause layer (TTL).

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

2011-11-10T23:59:59.000Z

29

A Characterization of Cirrus Cloud Properties That Affect Laser Propagation  

Science Conference Proceedings (OSTI)

Future high-altitude laser systems may be affected by cirrus clouds. Laser transmission models were applied to measured and retrieved cirrus properties to determine cirrus impact on power incident on a target or receiver. A major goal was to see ...

Donald C. Norquist; Paul R. Desrochers; Patrick J. McNicholl; John R. Roadcap

2008-05-01T23:59:59.000Z

30

ARM - Publications: Science Team Meeting Documents: Cirrus Cloud...  

NLE Websites -- All DOE Office Websites (Extended Search)

Cirrus Cloud Measurements by the UAF Polarization Diversity Lidar during M-PACE Sassen, Kenneth University of Alaska Fairbanks Zhu, Jiang UAF During the final week of the...

31

Seasonal and Diurnal Changes in Cirrus Clouds as Seen in Four Years of Observations with the VAS  

Science Conference Proceedings (OSTI)

GOES VAS multispectral observations in the carbon dioxide absorption band at 15 ?m have been used to compile cloud-cover statistics over the continental United States for the past 4 years. The CO2 technique calculates both cloud-top pressures and ...

W. P. Menzel; D. P. Wylie; K. I. Strabala

1992-04-01T23:59:59.000Z

32

The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution Shape d'Entremont, Robert Atmospheric and Environmental Research, Inc. Mitchell, David Desert Research Institute Category: Cloud Properties Our project has focused on using satellite- and ground-based passive thermal infrared radiance observations to retrieve cirrus cloud properties, most importantly ice water path (IWP), effective particle size (Deff), and visible extinction optical thickness (tau). During this past year we began comparing our cirrus retrieval results with aircraft observations at the ARM CART site, and we are participating in a summary intercomparison study with other retrieval algorithms as a member of the high-clouds working group. Our passive-infrared retrieval scheme, based on different wavelength

33

A Numerical Study of Cirrus Clouds. Part I: Model Description  

Science Conference Proceedings (OSTI)

This article, the first of a two-part series, presents a detailed description of a two-dimensional numerical cloud model directed toward elucidating the physical processes governing the evolution of cirrus clouds. The two primary scientific ...

Hui-Chun Liu; Pao K. Wang; Robert E. Schlesinger

2003-04-01T23:59:59.000Z

34

Evaluation of Cirrus Parameterizations for Radiative Flux Computations in Climate Models Using TOVS–ScaRaB Satellite Observations  

Science Conference Proceedings (OSTI)

Combined simultaneous satellite observations are used to evaluate the performance of parameterizations of the microphysical and optical properties of cirrus clouds used for radiative flux computations in climate models. Atmospheric and cirrus ...

C. J. Stubenrauch; F. Eddounia; J. M. Edwards; A. Macke

2007-09-01T23:59:59.000Z

35

The Remote Sensing of Thin Cirrus Cloud Using Satellites, Lidar and Radiative Transfer Theory  

Science Conference Proceedings (OSTI)

The problem of retrieving cirrus cloud optical depth from radiance measurements made by instruments aboard operational meteorological satellites is addressed. A method is proposed that exploits the relationship between observed differences in the ...

Robert S. Stone; Graeme L. Stephens; C. M. R. Platt; S. Banks

1990-05-01T23:59:59.000Z

36

An Accurate Parameterization of the Solar Radiative Properties of Cirrus Clouds for Climate Models  

Science Conference Proceedings (OSTI)

An accurate parameterization of the solar radiative properties of cirrus clouds is developed based on improved light scattering calculations. Here 28 ice crystal size distributions from in situ aircraft observations in both tropical and ...

Qiang Fu

1996-09-01T23:59:59.000Z

37

Tropical Tropopause Transition Layer Cirrus as Represented by CALIPSO Lidar Observations  

Science Conference Proceedings (OSTI)

The spatial and temporal variability of cirrus cloud fraction within the tropical tropopause transition layer (TTL) is investigated based on three years of data from the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) ...

Katrina S. Virts; John M. Wallace; Qiang Fu; Thomas P. Ackerman

2010-10-01T23:59:59.000Z

38

Inference of Cirrus Cloud Properties Using Satellite-observed Visible and Infrared Radiances. Part I: Parameterization of Radiance Fields  

Science Conference Proceedings (OSTI)

Current techniques for deriving cirrus optical depth and altitude from visible (0.65 ?m) and infrared (11.5 ?m) satellite data use radiative transfer calculations based on scattering phase functions of spherical water droplets. This study ...

Patrick Minnis; Kuo-Nan Liou; Yoshihide Takano

1993-05-01T23:59:59.000Z

39

Time Correlations in Backscattering Radar Reflectivity Measurements from Cirrus Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

Time Correlations in Backscattering Radar Reflectivity Time Correlations in Backscattering Radar Reflectivity Measurements from Cirrus Clouds K. Ivanova, H. N. Shirer, and E. E. Clothiaux Pennsylvania State University University Park, Pennsylvania T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington Introduction The state variables of the atmosphere exhibit correlations at various spatial and temporal scales. These correlations are crucial for understanding short- and long-term trends in climate. Cirrus clouds are important phenomena in the troposphere affecting climate. To improve future parameterization of cirrus clouds in climate models, we must understand the cloud properties and how they change within the cloud. We consider fluctuations of cloud radar signals obtained at isodepths within cirrus clouds

40

Tropical anvil cirrus evolution from observations and numerical...  

NLE Websites -- All DOE Office Websites (Extended Search)

cirrus evolution from observations and numerical simulations Deng, Min University of Utah Mace, Gerald University of Utah Category: Modeling The tropical anvil cirrus formation...

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Remote sensing of cirrus cloud particle size and optical depth using polarimetric sensor measurements  

E-Print Network (OSTI)

and J. Pelon, 1999b: Remote sensing of cirrus radiativepar- ticles: Remote sensing and climatic implications.S. C. Tsay, 1999: Remote sensing of cirrus cloud parameters

Ou, Szu-cheng C; Liou, K N; Takano, Y; Slonaker, R L

2005-01-01T23:59:59.000Z

42

Radiative Properties of Cirrus Clouds in the Infrared Region  

Science Conference Proceedings (OSTI)

A multiple-scattering radiative transfer model is employed to evaluate the 11 ?m and the broad-band infrared (IR) fluxes, cooling rates and emittances in model cirrus clouds for a number of standard vertical atmospheric profiles of temperature ...

Graeme L. Stephens

1980-02-01T23:59:59.000Z

43

Supersaturation Fluctuations in Cirrus Clouds Driven by Colored Noise  

Science Conference Proceedings (OSTI)

Fundamental properties of ice supersaturation variability in cirrus clouds are studied by means of an idealized probabilistic model. Damped supersaturation fluctuations are assumed to be exponentially correlated in time, statistically stationary, ...

B. Kärcher

2012-02-01T23:59:59.000Z

44

Evaluation of Tropical Cirrus Cloud Properties and Dynamical...  

NLE Websites -- All DOE Office Websites (Extended Search)

through the TTL into the stratosphere. The ability of large-scale models to correctly forecast tropical cirrus occurrence is important in predicting the role of these clouds on...

45

A Methodology for Measuring Cirrus Cloud Visible-to-Infrared Spectral Optical Depth Ratios  

Science Conference Proceedings (OSTI)

Knowledge of cirrus cloud optical depths is necessary to understand the earth’s current climate and to model the cloud radiation impact on future climate. Cirrus clouds, depending on the ratio of their shortwave “visible” to longwave “infrared” ...

Daniel H. DeSlover; William L. Smith; Paivi K. Piironen; Edwin W. Eloranta

1999-02-01T23:59:59.000Z

46

A Summary of the Physical Properties of Cirrus Clouds  

Science Conference Proceedings (OSTI)

A review of existing literature is made to determine typical values for the physical properties cirrus clouds. The properties examined (with typical values and measured ranges) are cloud-center altitude (9 km, 4 to 20 km), cloud thickness (1.5 km,...

David R. Dowling; Lawrence F. Radke

1990-09-01T23:59:59.000Z

47

A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations  

Science Conference Proceedings (OSTI)

An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA’s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined ...

Lin Tian; Gerald M. Heymsfield; Lihua Li; Andrew J. Heymsfield; Aaron Bansemer; Cynthia H. Twohy; Ramesh C. Srivastava

2010-01-01T23:59:59.000Z

48

Cirrus Classification at Midlatitude from Systematic Lidar Observations  

Science Conference Proceedings (OSTI)

Systematic cirrus lidar measurements performed in the south of France during 2000 are analyzed statistically to search for cloud classes. The classes are based on cloud characteristics (cloud thickness, light backscattering efficiency, and its ...

P. Keckhut; F. Borchi; S. Bekki; A. Hauchecorne; M. SiLaouina

2006-02-01T23:59:59.000Z

49

Observations of temperature, wind, cirrus, and trace gases in the tropical tropopause transition layer during the MJO  

Science Conference Proceedings (OSTI)

Satellite observations of temperature, optically thin cirrus clouds, and trace gases derived from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), Cloud-Aerosol Lidar and Infrared Pathfinder Satellite ...

Katrina S. Virts; John M. Wallace

50

The 27–28 October 1986 FIRE IFO Cirrus Case Study: Cloud Microstructure  

Science Conference Proceedings (OSTI)

The temperature and windfield structure and hydrometeor composition of cirrus clouds sampled by the NCAR King Air and Sabreliner aircraft on 28 October 1986 near Madison, Wisconsin are described as part of a case study that examines cirrus cloud ...

Andrew J. Heymsfield; Karen M. Miller; James D. Spinhirne

1990-11-01T23:59:59.000Z

51

Influence of Cirrus Clouds on Weather and Climate Processes: A Global Perspective  

Science Conference Proceedings (OSTI)

Current understanding and knowledge of the composition and structure of cirrus clouds are reviewed and documented in this paper. In addition, the radiative properties of cirrus clouds as they relate to weather and climate processes are described ...

Kuo-Nan Liou

1986-06-01T23:59:59.000Z

52

Radiative Heating Profiles in Simple Cirrus Cloud Systems  

Science Conference Proceedings (OSTI)

Results from one-dimensional cirrus cloud model simulations in the absence of upward velocities are used to show that the growth/sublimation of the ice particles in the cloud, and the fact that they are falling, can be important factors in ...

Andrew Detwiler; V. Ramaswamy

1990-09-01T23:59:59.000Z

53

Cirrus Cloud Ice Water Content Radar Algorithm Evaluation Using an Explicit Cloud Microphysical Model  

Science Conference Proceedings (OSTI)

A series of cirrus cloud simulations performed using a model with explicit cloud microphysics is applied to testing ice water content retrieval algorithms based on millimeter-wave radar reflectivity measurements. The simulated ice particle size ...

Kenneth Sassen; Zhien Wang; Vitaly I. Khvorostyanov; Graeme L. Stephens; Angela Bennedetti

2002-06-01T23:59:59.000Z

54

Radiative Transfer in Cirrus Clouds. Part IV: On Cloud Geometry, Inhomogeneity, and Absorption  

Science Conference Proceedings (OSTI)

The effects of cloud geometry and inhomogeneity on the radiative properties of cirrus clouds are investigated by using the successive orders of scattering (SOS) approach for radiative transfer. This approach is an integral solution method that em ...

K. N. Liou; N. Rao

1996-11-01T23:59:59.000Z

55

A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part II: Microphysical Properties Derived from Lidar Depolarization  

Science Conference Proceedings (OSTI)

In Part II of this series of papers describing the results of the extended time observations of cirrus clouds from the University of Utah Facility for Atmospheric Remote Sensing (FARS), the information content of laser backscatter depolarization ...

Kenneth Sassen; Sally Benson

2001-08-01T23:59:59.000Z

56

Sensitivity Analysis of Cirrus Cloud Properties from High-Resolution Infrared Spectra. Part I: Methodology and Synthetic Cirrus  

Science Conference Proceedings (OSTI)

A set of simulated high-resolution infrared (IR) emission spectra of synthetic cirrus clouds is used to perform a sensitivity analysis of top-of-atmosphere (TOA) radiance to cloud parameters. Principal component analysis (PCA) is applied to ...

Brian H. Kahn; Annmarie Eldering; Michael Ghil; Simona Bordoni; Shepard A. Clough

2004-12-01T23:59:59.000Z

57

Cirrus Infrared Parameters and Shortwave Reflectance Relations from Observations  

Science Conference Proceedings (OSTI)

A summary of experimental observations and analysis of cirrus from high-altitude aircraft remote sensing is presented. The vertical distribution of cirrus optical and infrared cross-section parameters and the relative effective emittance and ...

James D. Spinhirne; William D. Hart; Dennis L. Hlavka

1996-05-01T23:59:59.000Z

58

In Situ Observation of Cirrus Scattering Phase Functions with 22° and 46° Halos: Cloud Field Study on 19 February 1998  

Science Conference Proceedings (OSTI)

Observations of halos and related phenomena due to ice crystals are commonly reported from ground observations and presented in the literature. Nevertheless, ice crystal characteristics have only been poorly documented from in situ measurements ...

Frederique Auriol; Jean-François Gayet; Guy Febvre; Olivier Jourdan; Laurent Labonnote; Gerard Brogniez

2001-11-01T23:59:59.000Z

59

The Properties and Formation of Cirrus Clouds over the Tibetan Plateau Based on Summertime Lidar Measurements  

Science Conference Proceedings (OSTI)

As part of the Tibet Ozone, Aerosol and Radiation (TOAR) project, a micropulse lidar was operated in Naqu (31.5°N, 92.1°E; 4508 m MSL) on the Tibetan Plateau to observe cirrus clouds continuously from 19 July to 26 August 2011. During the ...

Q. S. He; C. C. Li; J. Z. Ma; H. Q. Wang; G. M. Shi; Z. R. Liang; Q. Luan; F. H. Geng; X. W. Zhou

2013-03-01T23:59:59.000Z

60

The 27–28 October 1986 FIRF IFO Cirrus Case Study: Comparison of Radiative Transfer Theory with Observations by Satellite and Aircraft  

Science Conference Proceedings (OSTI)

Observations of cirrus and altocumulus clouds during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) are compared to theoretical models of cloud radiative properties. Three tests are performed. First, ...

Bruce A. Wielicki; J.T. Suttles; Andrew J. Heymsfield; Ronald M. Welch; James D. Spinhirne; Man-Li C. Wu; David O'C. Starr; Lindsay Parker; Robert F. Arduini

1990-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Lidar Network Observations of Cirrus Morphological and Scattering Properties during the International Cirrus Experiment 1989: The 18 October 1989 Case Study and Statistical Analysis  

Science Conference Proceedings (OSTI)

Four lidars located roughly 75 km from each other in the inner German Bight of the North Sea, were used to measure geometrical and optical properties of cirrus clouds during the International Cirrus Experiment 1989 (ICE '89). A complete cirrus ...

Albert Ansmann; Jens Bösenberg; Gérard Brogniez; Salem Elouragini; Pierre H. Flamant; Karlheinz Klapheck; Holger Linn; Louis Menenger; Walfried Michaelis; Maren Riebesell; Christoph Senff; Pierre-Yves Thro; Ulla Wandinger; Claus Weitkamp

1993-10-01T23:59:59.000Z

62

The 27–28 October 1986 FIRE IFO Cirrus Case Study: Spectral Properties of Cirrus Clouds in the 8–12 ?m Window  

Science Conference Proceedings (OSTI)

Lidar and high spectral resolution infrared radiance observations taken on board the ER-2 on 28 October 1986 are used to study the radiative properties of cirrus cloud in the 8–12 ?m window region. Measurements from the High-spectral resolution ...

Steven A. Ackerman; W. L. Smith; H. E. Revercomb; J. D. Spinhirne

1990-11-01T23:59:59.000Z

63

The Mysteries of Mammatus Clouds: Observations and Formation Mechanisms  

Science Conference Proceedings (OSTI)

Mammatus clouds are an intriguing enigma of atmospheric fluid dynamics and cloud physics. Most commonly observed on the underside of cumulonimbus anvils, mammatus also occur on the underside of cirrus, cirrocumulus, altocumulus, altostratus, and ...

David M. Schultz; Katharine M. Kanak; Jerry M. Straka; Robert J. Trapp; Brent A. Gordon; Dusan S. Zrni?; George H. Bryan; Adam J. Durant; Timothy J. Garrett; Petra M. Klein; Douglas K. Lilly

2006-10-01T23:59:59.000Z

64

Cirrus Microphysics and Radiative Transfer: Cloud Field Study on 28 October 1986  

Science Conference Proceedings (OSTI)

Cloud data acquired during the cirrus intensive field operation of FIRE 86 are analyzed for a 75 × 50-km2 cirrus cloud field that passed over Wausau, Wisconsin, during the morning of 28 October 1986. Remote-sensing measurements from the ...

Stefan Kinne; Thomas P. Ackerman; Andrew J. Heymsfield; Francisco P. J. Valero; Kenneth Sassen; James D. Spinhirne

1992-05-01T23:59:59.000Z

65

Parameterization and Impact of Ice initiation Processes Relevant to Numerical Model Simulations of Cirrus Clouds  

Science Conference Proceedings (OSTI)

An effort to improve descriptions of ice initiation processes of relevance to cirrus clouds for use in regional-scale numerical cloud models with bulk microphysical schemes is described. This is approached by deriving practical parameterizations ...

Paul J. DeMott; Michael P. Meyers; William R. Cotton

1994-01-01T23:59:59.000Z

66

The Composite Characteristics of Cirrus Clouds: Bulk Properties Revealed by One Year of Continuous Cloud Radar Data  

Science Conference Proceedings (OSTI)

The properties of midlatitude cirrus clouds are examined using one year of continuous vertically pointing millimeter-wave cloud radar data collected at the Atmospheric Radiation Measurement Program Southern Great Plains site in Oklahoma. The goal ...

Gerald G. Mace; Eugene E. Clothiaux; Thomas P. Ackerman

2001-05-01T23:59:59.000Z

67

Determination of Effective Emittance and a Radiatively Equivalent Microphysical Model of Cirrus from Ground-Based and Satellite Observations during the International Cirrus Experiment: The 18 October 1989 Case Study  

Science Conference Proceedings (OSTI)

Ground-based observations and satellite data have been compared for the 18 October 1989 case study of the International Cirrus Experiment (ICE) field campaign. They correspond to thin cirrus clouds with infrared emittances in the range 0–0.3. ...

G. Brogniez; J. C. Buriez; V. Giraud; F. Parol; C. Vanbauce

1995-04-01T23:59:59.000Z

68

Detecting and Evaluating the Effect of Overlaying Thin Cirrus Cloud on MODIS Retrieved Water-Cloud Droplet Effective Radius  

NLE Websites -- All DOE Office Websites (Extended Search)

Detecting and Evaluating the Effect Detecting and Evaluating the Effect of Overlaying Thin Cirrus Cloud on MODIS Retrieved Water-Cloud Droplet Effective Radius F.-L Chang and Z. Li Earth System Science Interdisciplinary Center University of Maryland College Park, Maryland Z. Li Department of Meteorology University of Maryland College Park, Maryland Introduction Cirrus clouds can largely modify the solar reflected and terrestrial emitted radiances. The ubiquitous presence of cirrus clouds has a global coverage of about 20% to30% and more than 70% in the tropics (Wylie et al. 1994). The probability of cirrus clouds overlaying a low-level boundary layer cloud system is greater than 50% (Hahn et al. 1982, 1984; Tian and Curry 1989; Mace et al. 1997). They are often optically thin and semitransparent and frequently reside in high altitude overlapping with a low-level

69

Cirrus Cloud Properties Derived from High Spectral Resolution Infrared Spectrometry during FIRE II. Part III: Ground-Based HIS Results  

Science Conference Proceedings (OSTI)

During FIRE II, cirrus clouds were observed in the wavelength range 3–19, µm with two High Resolution Interferometer Sounders as described in the Part I companion paper. One, known as AC-HIS, was mounted on the NASA ER-2 aircraft in order to look ...

A. D. Collard; S. A. Ackerman; W. L. Smith; X. Ma; H. E. Revercomb; R. O. Knuteson; S-C. Lee

1995-12-01T23:59:59.000Z

70

Remote Sensing of Cirrus Cloud Particle Size and Optical Depth Using Polarimetric Sensor Measurements  

Science Conference Proceedings (OSTI)

This paper presents a conceptual approach toward the remote sensing of cirrus cloud particle size and optical depth using the degree of polarization and polarized reflectance associated with the first three Stokes parameters, I, Q, and U, for the ...

S. C. Ou; K. N. Liou; Y. Takano; R. L. Slonaker

2005-12-01T23:59:59.000Z

71

A New Parameterization of an Asymmetry Factor of Cirrus Clouds for Climate Models  

Science Conference Proceedings (OSTI)

The aspect ratio (AR) of a nonspherical ice particle is identified as the key microphysical parameter to determine its asymmetry factor for solar radiation. The mean effective AR is defined for cirrus clouds containing various nonspherical ice ...

Qiang Fu

2007-11-01T23:59:59.000Z

72

Retrieval of Vertical Profiles of Cirrus Cloud Microphysical Parameters from Doppler Radar and Infrared Radiometer Measurements  

Science Conference Proceedings (OSTI)

This paper describes a new method to retrieve vertical profiles of the parameters of cirrus cloud microphysics that are important for the estimation of climatic feedback. These parameters are the particle characteristic size and ice mass content. ...

S. Y. Matrosov; B. W. Orr; R. A. Kropfli; J. B. Snider

1994-05-01T23:59:59.000Z

73

Determination of Semi-Transparent Cirrus Cloud Temperature from Infrared Radiances: Application to METEOSAT  

Science Conference Proceedings (OSTI)

The use of simultaneous infrared measurements to derive the temperature and emissivity of semi-transparent cirrus clouds is experimentally investigated. Results from the NASA/CONVAIR-990 Winter Experiment Program, 1977 (WEP) are discussed. It is ...

Gerard Szejwach

1982-03-01T23:59:59.000Z

74

A Comparison of Cirrus Cloud Visible Optical Depth Derived from Lidar  

NLE Websites -- All DOE Office Websites (Extended Search)

Comparison of Cirrus Cloud Visible Optical Depth Derived from Lidar Comparison of Cirrus Cloud Visible Optical Depth Derived from Lidar Lo, Chaomei Pacific Northwest National Laboratory Comstock, Jennifer Pacific Northwest National Laboratory Flynn, Connor Pacific Northwest National Laboratory Category: Cloud Properties Optically thin clouds (e.g. optical depth < 3) can have a significant impact on radiative heating in the atmosphere, particularly in the cold upper troposphere. Currently, there is no value-added product (VAP) in the Atmospheric Radiation Measurement (ARM) program archive that produces thin cloud optical depth, particularly at the Tropical Western Pacific and North Slope of Alaska sites. A VAP is under development to obtain the cirrus cloud visible optical depth from the MPLNOR (Micro Pulse Lidar Normalized

75

The Impact of Ice Crystal Shapes, Size Distributions, and Spatial Structures of Cirrus Clouds on Solar Radiative Fluxes  

Science Conference Proceedings (OSTI)

The solar radiative properties of cirrus clouds depend on ice particle shape, size, and orientation, as well as on the spatial cloud structure. Radiation schemes in atmospheric circulation models rely on estimates of cloud optical thickness only. ...

I. Schlimme; A. Macke; J. Reichardt

2005-07-01T23:59:59.000Z

76

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

DOE Green Energy (OSTI)

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

Kuo-Nan Liou

2003-12-29T23:59:59.000Z

77

Cirrus Cloud Properties and the Large-Scale Meteorological Environment: Relationships Derived from A-Train and NCEP–NCAR Reanalysis Data  

Science Conference Proceedings (OSTI)

Empirical knowledge of how cirrus cloud properties are coupled with the large-scale meteorological environment is a prerequisite for understanding the role of microphysical processes in the life cycle of cirrus cloud systems. Using active and ...

Elizabeth Berry; Gerald G. Mace

2013-05-01T23:59:59.000Z

78

The 27–28 October 1986 FIRE IFO Cirrus Case Study: A Five Lidar Overview of Cloud Structure and Evolution  

Science Conference Proceedings (OSTI)

Optical remote sensing measurements of cirrus cloud properties were collected by one airborne and four ground-based lidar systems over a 32-h period during this cue study from the First ISCCP (International Satellite Cloud Climatology Program) ...

Kenneth Sassen; Christian J. Grund; James D. Spinhirne; Michael M. Hardesty; Jose M. Alvarez

1990-11-01T23:59:59.000Z

79

Improved Detection of Optically Thin Cirrus Clouds in Nighttime Multispectral Meteorological Satellite Imagery Using Total Integrated Water Vapor Information  

Science Conference Proceedings (OSTI)

The accurate identification of optically thin cirrus clouds in global meteorological satellite imagery by automated cloud analysis algorithms is critical to environmental remote sensing studies, such as those related to climate change. While ...

Keith D. Hutchison; Kenneth R. Hardy; Bo-Cai Gao

1995-05-01T23:59:59.000Z

80

Evaluate the Effect of Upper-Level Cirrus Clouds on Satellite Retrievals of Low-Level Cloud Droplet Effective Radius  

NLE Websites -- All DOE Office Websites (Extended Search)

the Effect of Upper-Level Cirrus Clouds the Effect of Upper-Level Cirrus Clouds on Satellite Retrievals of Low-Level Cloud Droplet Effective Radius F.-L. Chang and Z. Li Earth System Science Interdisciplinary Center University of Maryland College Park, Maryland Z. Li Department of Meteorology University of Maryland College Park, Maryland Introduction The earth's radiation budget is sensitive to changes in the microphysical properties of low-level stratiform clouds. Their extensive coverage can significantly reduce the solar energy absorbed by the earth system. An estimate of reducing the global-mean droplet effective radius (r e ) of these low-level clouds by ~2 µm, while keeping the column liquid water constant would balance the warming due to CO 2 doubling in the atmosphere (Slingo 1990). Accurate determination of the droplet r

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Measurements of the Total Water Content of Cirrus Clouds. Part II: Instrument Performance and Validation  

Science Conference Proceedings (OSTI)

This paper describes the performance and in-flight validation of an instrument mounted in a pallet on the NASA WB-57 research aircraft that measures the sum of gas phase and solid phase water, or total water, in cirrus clouds. Using a heated ...

E. M. Weinstock; J. B. Smith; D. Sayres; J. V. Pittman; N. Allen; J. G. Anderson

2006-11-01T23:59:59.000Z

82

Measurements of the Total Water Content of Cirrus Clouds. Part I: Instrument Details and Calibration  

Science Conference Proceedings (OSTI)

This paper describes an instrument designed to measure the sum of gas phase and solid phase water, or total water, in cirrus clouds, and to be mounted in a pallet in the underbelly of the NASA WB-57 research aircraft. The ice water content of ...

E. M. Weinstock; J. B. Smith; D. Sayres; J. R. Spackman; J. V. Pittman; N. Allen; J. Demusz; M. Greenberg; M. Rivero; L. Solomon; J. G. Anderson

2006-11-01T23:59:59.000Z

83

Modeling Cirrus Clouds. Part I: Treatment of Bimodal Size Spectra and Case Study Analysis  

Science Conference Proceedings (OSTI)

A model has been developed that predicts the evolution of bimodal size spectra in cirrus clouds. This was done by predicting two size distributions: one for ice particles less than about 150 µm and another for larger particles. The sum of these ...

David L. Mitchell; Steven K. Chai; Yangang Liu; Andrew J. Heymsfield; Yayi Dong

1996-10-01T23:59:59.000Z

84

The Optical Properties of Equatorial Cirrus from Observations in the ARM Pilot Radiation Observation Experiment  

Science Conference Proceedings (OSTI)

The optical properties of equatorial cirrus were studied during a three-week period of the ARM Pilot Radiation and Observation Experiment at Kavieng, Papua New Guinea, in January and February 1993. The experiment consisted of vertical lidar (532 ...

C. M. R. Platt; S. A. Young; P. J. Manson; G. R. Patterson; S. C. Marsden; R. T. Austin; J. H. Churnside

1998-06-01T23:59:59.000Z

85

Sensitivity Studies of Dust Ice Nuclei Effect on Cirrus Clouds with the Community Atmosphere Model CAM5  

SciTech Connect

In this study the effect of dust aerosol on upper tropospheric cirrus clouds through heterogeneous ice nucleation is investigated in the Community Atmospheric Model version 5 (CAM5) with two ice nucleation parameterizations. Both parameterizations consider homogeneous and heterogeneous nucleation and the competition between the two mechanisms in cirrus clouds, but differ significantly in the number concentration of heterogeneous ice nuclei (IN) from dust. Heterogeneous nucleation on dust aerosol reduces the occurrence frequency of homogeneous nucleation and thus the ice crystal number concentration in the Northern Hemisphere (NH) cirrus clouds compared to simulations with pure homogeneous nucleation. Global and annual mean shortwave and longwave cloud forcing are reduced by up to 2.0 ± 0.1 W m?2 (1? uncertainty) and 2.4 ± 0.1 W m?2, respectively due to the presence of dust IN, with the net cloud forcing change of ?0.40 ± 0.20 W m?2. Comparison of model simulations with in situ aircraft data obtained in NH mid-latitudes suggests that homogeneous ice nucleation may play an important role in the ice nucleation at these regions with temperatures of 205–230 K. However, simulations overestimate observed ice crystal number concentrations in the tropical tropopause regions with temperatures of 190–205 K, and overestimate the frequency of occurrence of high ice crystal number concentration (> 200 L?1) and underestimate the frequency of low ice crystal number concentration (< 30 L?1) at NH mid-latitudes. These results highlight the importance of quantifying the number concentrations and properties of heterogeneous IN (including dust aerosol) in the upper troposphere from the global perspective.

Liu, Xiaohong; Shi, Xiangjun; Zhang, Kai; Jensen, Eric; Gettelman, A.; Barahona, Donifan; Nenes, Athanasios; Lawson, Paul

2012-12-19T23:59:59.000Z

86

The Role of Ice Particle Shapes and Size Distributions in the Single Scattering Properties of Cirrus Clouds  

Science Conference Proceedings (OSTI)

The roles of ice particle size distributions (SDs) and particle shapes in cirrus cloud solar radiative transfer are investigated by analyzing SDs obtained from optical array probe measurements (particle sizes larger than 20–40 ?m) during ...

Andreas Macke; Peter N. Francis; Greg M. McFarquhar; Stefan Kinne

1998-09-01T23:59:59.000Z

87

Information Content of AVHRR Channels 4 and 5 with Respect to the Effective Radius of Cirrus Cloud Particles  

Science Conference Proceedings (OSTI)

This paper investigates the important difference in the relationship between brightness temperatures between the 11-?m and the 12-?n AVHRR data and the microphysical properties of the semitransparent cirrus clouds. In the nonscattering ...

F. Parol; J. C. Buriez; G. Brogniez; Y. Fouquart

1991-07-01T23:59:59.000Z

88

The 27–28 October 1986 FIRE IFO Cirrus Case Study: Cloud Optical Properties Determined by High Spectral Resolution Lidar  

Science Conference Proceedings (OSTI)

During the FIRE cirrus IFO, the High Spectral Resolution Lidar (HSRL) was operated from a roof top site on the University of Wisconsin–Madison campus. Because the HSRL technique separately measures the molecular and cloud particle backscatter ...

C. J. Grund; E. W. Eloranta

1990-11-01T23:59:59.000Z

89

Detection of Multilayer Cirrus Cloud Systems Using AVHRR Data: Verification Based on FIRE II IFO Composite Measurements  

Science Conference Proceedings (OSTI)

A numerical scheme has been developed to identify multilayer cirrus cloud systems using Advanced Very Higher Resolution Radiometer (AVHRR) data. It is based on the physical properties of the AVHRR channels 1?2 reflectance ratios, the brightness ...

S. C. Ou; K. N. Liou; B. A. Baum

1996-02-01T23:59:59.000Z

90

Demonstration Measurements of Water Vapor, Cirrus Clouds, and Carbon Dioxide Using a High-Performance Raman Lidar  

Science Conference Proceedings (OSTI)

Profile measurements of atmospheric water vapor, cirrus clouds, and carbon dioxide using the Raman Airborne Spectroscopic lidar (RASL) during ground-based, upward-looking tests are presented here. These measurements improve upon any previously ...

David N. Whiteman; Kurt Rush; Igor Veselovskii; Martin Cadirola; Joseph Comer; John R. Potter; Rebecca Tola

2007-08-01T23:59:59.000Z

91

Cirrus Cloud Microphysical Property Retrieval Using Lidar and Radar Measurements. Part I: Algorithm Description and Comparison with In Situ Data  

Science Conference Proceedings (OSTI)

A retrieval algorithm is described to estimate vertical profiles of cirrus-cloud ice water content (IWC) and general effective size Dge from combined lidar and radar measurements. In the algorithm, the lidar extinction coefficient ? is ...

Zhien Wang; Kenneth Sassen

2002-03-01T23:59:59.000Z

92

Detecting Cirrus-Overlapping-Water Clouds and Retrieving their...  

NLE Websites -- All DOE Office Websites (Extended Search)

Different methods have been proposed to detect multilayer clouds using passive remote sensing data. Baum et al. (1995) used the CO 2 -slicing technique applied to the...

93

ARM - Field Campaign - WB57 Midlatitude Cirrus Cloud Experiment...  

NLE Websites -- All DOE Office Websites (Extended Search)

invested considerable effort in characterizing clouds with instruments ranging from passive remote sensors on board the EOS platforms, to active remote sensors on Cloudsat and...

94

Evolution of a Florida Cirrus Anvil  

Science Conference Proceedings (OSTI)

This paper presents a detailed study of a single thunderstorm anvil cirrus cloud measured on 21 July 2002 near southern Florida during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL-FACE). ...

T. J. Garrett; B. C. Navarro; C. H. Twohy; E. J. Jensen; D. G. Baumgardner; P. T. Bui; H. Gerber; R. L. Herman; A. J. Heymsfield; P. Lawson; P. Minnis; L. Nguyen; M. Poellot; S. K. Pope; F. P. J. Valero; E. M. Weinstock

2005-07-01T23:59:59.000Z

95

Homogeneous Nucleation Rate for Highly Supercooled Cirrus Cloud Droplets  

Science Conference Proceedings (OSTI)

A mixed-phase hydrometer growth model has been applied to determining the nucleation mode and rate responsible for the glaciation of a highly supercooled liquid cloud studied jointly by ground-based polarization lidar and aircraft in situ probes. ...

Kenneth Sassen; Gregory C. Dodd

1988-04-01T23:59:59.000Z

96

A Model Predicting the Evolution of Ice Particle Size Spectra and Radiative Properties of Cirrus Clouds. Part I: Microphysics  

Science Conference Proceedings (OSTI)

A Lagrangian time-dependent three-dimensional model was developed that predicts the evolution of ice particle size spectra in cirrus clouds in terms of the growth processes of vapor diffusion and aggregation, as well as the cloud updraft profile. ...

David L. Mitchell

1994-03-01T23:59:59.000Z

97

Possible Influence of Anthropogenic Aerosols on Cirrus Clouds and Anthropogenic Forcing  

DOE Green Energy (OSTI)

Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth’s area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We find that fossil fuel and biomass burning soot aerosols exert a radiative forcing of -0.68 to 0.01 Wm-2 while anthropogenic sulfate aerosols exert a forcing of -0.01 to 0.18 Wm-2. Our calculations show that the sign of the forcing by aircraft soot depends on the model configuration and can be both positive or negative, ranging from -0.16 to 0.02 Wm-2. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

Penner, Joyce E.; Chen, Yang; Wang, Minghuai; Liu, Xiaohong

2009-02-03T23:59:59.000Z

98

Microphysical and Optical Properties of Cirrus and Contrails: Cloud Field Study on 13 October 1989  

Science Conference Proceedings (OSTI)

During the intensive International Cirrus Experiment conducted over the North Sea during fall 1989, natural cirrus and contrail-induced cirrus were analyzed from in situ and remote sensing measurements (lidar and infrared radiometer). These two ...

Jean-François Gayet; Guy Febvre; Gerard Brogniez; Helene Chepfer; Wolfgang Renger; Peter Wendling

1996-01-01T23:59:59.000Z

99

Satellite-based remote sensing of cirrus clouds: hyperspectral radiative transfer modeling, analysis of uncertainties in in-situ cloud extinction measurements and intercomparison of cirrus retrievals from a-train instruments  

E-Print Network (OSTI)

This dissertation consists of three parts, each devoted to a particular issue of significant importance for satellite-based remote sensing of cirrus clouds. In the first part, we develop and present a fast infrared radiative transfer model on the basis of the adding-doubling principle. The model aims to facilitate the radiative transfer computations involved in hyperspectral remote sensing applications. The model is applicable to a variety of cloud conditions, including vertically inhomogeneous or multilayered clouds. It is shown that for hyperspectral applications the model is two order-of-magnitude faster than the well-known discrete ordinate transfer (DISORT) model, while maintains a similar accuracy. The second part is devoted to the investigation of uncertainties in the FSSP (Forward Scattering Spectrometer Probe) measurement of cloud extinction by small ice particles. First, the single-scattering properties of small ice particles in cirrus clouds are derived and compared to those of equivalent spheres according to various definitions. It is found that, although small ice particles in cirrus clouds are often “quasi-spherical”, their scattering phase functions and asymmetry factors are significant different from those of ice spheres. Such differences may lead to substantial underestimation of cloud extinction in FSSP measurement, if small ice particles are assumed to be spheres. In the third part, we present a comparison of cirrus cloud optical thickness retrievals from two important instruments, MODIS (Moderate Resolution Imaging Spectrometer) and POLDER (Polarization and Directionality of Earth’s Reflection), on board NASA’s A-train satellite constellation. The comparison reveals a large difference. Several possible reasons are discussed. It is found that much of the difference is attributable to the difference between the MODIS and POLDER retrieval algorithm in the assumption of cirrus cloud bulk scattering properties. Potential implications of the difference for climate studies are investigated. An important finding is that the use of an unrealistic cirrus bulk scattering model might introduce artificial seasonal variation of cirrus optical thickness and shortwave radiative forcing into the retrieval.

Zhang, Zhibo

2008-08-01T23:59:59.000Z

100

An Automated Cirrus Cloud Detection Method for a Ground-Based Cloud Image  

Science Conference Proceedings (OSTI)

Cloud detection is a basic research for achieving cloud-cover state and other cloud characteristics. Because of the influence of sunlight, the brightness of sky background on the ground-based cloud image is usually nonuniform, which increases the ...

Jun Yang; Weitao Lu; Ying Ma; Wen Yao

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Remote Sensing of Cirrus Radiative Parameters during EUCREX’94. Case Study of 17 April 1994. Part I: Observations  

Science Conference Proceedings (OSTI)

During the intensive European Cloud and Radiation Experiment 1994 (EUCREX’94) conducted off the coast of Brittany (France) over the Atlantic Ocean during April 1994, natural cirrus have been analyzed from in situ and remote sensing measurements. ...

Laurent Sauvage; Pierre H. Flamant; Hélčne Chepfer; Gérard Brogniez; Vincent Trouillet; Jacques Pelon; Franck Albers

1999-04-01T23:59:59.000Z

102

Optical Depth Measurements of Aerosol Cloud, and Water Vapor Using Sun Photometers during FIRE Cirrus IFO II  

Science Conference Proceedings (OSTI)

Optical depths in the visible to infrared spectral region were obtained from solar extinction measurements with two sun photometers during the First ISCCP Regional Experiment Phase II Cirrus Intensive Field Observation in Kansas.

Masataka Shiobara; James D. Spinhirne; Akihiro Uchiyama; Shoji Asano

1996-01-01T23:59:59.000Z

103

A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part III: Radiative Properties  

Science Conference Proceedings (OSTI)

In Part III of a series of papers describing the extended time high-cloud observations from the University of Utah Facility for Atmospheric Remote Sensing (FARS) supporting the First International Satellite Cloud Climatology Project (ISCCP) ...

Kenneth Sassen; Jennifer M. Comstock

2001-08-01T23:59:59.000Z

104

Wavelet Analysis of Cirrus Multiscale Structures from Lidar Backscattering: A Cirrus Uncinus Complex Case Study  

Science Conference Proceedings (OSTI)

Although cirrus cloud structures play an important role in dynamics issues, cloud radiative calculations, and cloud parameter retrievals from satellite measurements, fully understanding cirrus cloud structures still remains a challenge. A case ...

Likun Wang; Kenneth Sassen

2008-10-01T23:59:59.000Z

105

Initialization and Validation of a Simulation of Cirrus Using FIRE-II Data  

Science Conference Proceedings (OSTI)

Observations from a wide variety of instruments and platforms are used to validate many different aspects of a three-dimensional mesoscale simulation of the dynamics, cloud microphysics, and radiative transfer of a cirrus cloud system observed on ...

D.L. Westphal; S. Kinne; P. Pilewskie; J.M. Alvarez; P. Minnis; D.F. Young; S.G. Benjamin; W.L. Eberhard; R.A. Kropfli; S.Y. Matrosov; J.B. Snider; T.A. Uttal; A.J. Heymsfield; G.G. Mace; S.H. Melfi; D.O'C. Starr; J.J. Soden

1996-12-01T23:59:59.000Z

106

Development and Comparison of Ground and Satellite-based Retrievals of Cirrus Cloud Physical Properties  

SciTech Connect

This report is the final update on ARM research conducted at DRI through May of 2006. A relatively minor amount of work was done after May, and last month (November), two journal papers partially funded by this project were published. The other investigator on this project, Dr. Bob d'Entremont, will be submitting his report in February 2007 when his no-cost extension expires. The main developments for this period, which concludes most of the DRI research on this project, are as follows: (1) Further development of a retrieval method for cirrus cloud ice particle effective diameter (De) and ice water path (IWP) using terrestrial radiances measured from satellites; (2) Revision and publication of the journal article 'Testing and Comparing the Modified Anomalous Diffraction Approximation'; and (3) Revision and publication of our radar retrieval method for IWC and snowfall rate.

Mitchell, David L

2009-10-14T23:59:59.000Z

107

Demonstrating the Potential for First-Class Research in Underdeveloped Countries: Research on Stratospheric Aerosols and Cirrus Clouds Optical Properties, and Radiative Effects in Cuba (1988–2010)  

Science Conference Proceedings (OSTI)

Optical properties of stratospheric aerosols and cirrus clouds and their radiative effects are currently important subjects of research worldwide. Those investigations are typical of developed countries, conducted by several highly specialized groups ...

Juan Carlos Antuńa Marrero; René Estevan Arredondo; Boris Barja González

2012-07-01T23:59:59.000Z

108

Subvisual-Thin Cirrus Lidar Dataset for Satellite Verification and Climatological Research  

Science Conference Proceedings (OSTI)

A polarization (0.694-?m wavelength) lidar dataset for subvisual and thin (bluish-colored) cirrus clouds is drawn from Project FIRE (First ISCCP Regional Experiment) extended time observations. The clouds are characterized by their day–night ...

Kenneth Sassen; Byung Sung Cho

1992-11-01T23:59:59.000Z

109

Annual, Interannual, and Intraseasonal Variability of Tropical Tropopause Transition Layer Cirrus  

Science Conference Proceedings (OSTI)

Cloud fields based on the first three years of data from the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission are used to investigate the relationship between cirrus within the tropical tropopause transition ...

Katrina S. Virts; John M. Wallace

2010-10-01T23:59:59.000Z

110

University of Wisconsin Cirrus Remote Sensing Pilot Experiment  

Science Conference Proceedings (OSTI)

During the period of 26 October 1989 through 6 December 1989 a unique complement of measurements was made at the University of Wisconsin—Madison to study the radiative properties of cirrus clouds. Simultaneous observations were obtained from a ...

Steven A. Ackerman; William L. Smith; Ed W. Eloranta; Chris J. Grund; Robert O. Knuteson; Henry E. Revercomb; Donald P. Wylie

1993-06-01T23:59:59.000Z

111

Cirrus Cloud Microphysical Property Retrieval Using Lidar and Radar Measurements. Part II: Midlatitude Cirrus Microphysical and Radiative Properties  

Science Conference Proceedings (OSTI)

The lidar–radar algorithm described in Part I of this set of papers is applied to 1000 h of Raman lidar and millimeter wave cloud radar (MMCR) data collected at the Atmospheric Radiation Measurement program Southern Great Plains Clouds and ...

Zhien Wang; Kenneth Sassen

2002-07-01T23:59:59.000Z

112

Identification of Small Ice Cloud Particles Using Passive Radiometric Observations  

Science Conference Proceedings (OSTI)

There is currently significant uncertainty about the extent to which cirrus clouds are composed of “small” ice crystals smaller than about 20-?m effective radius. This is due in part to concerns that in situ measurements from aircraft are plagued ...

Steven J. Cooper; Timothy J. Garrett

2010-11-01T23:59:59.000Z

113

Cirrus Microphysical Properties and Air Motion Statistics Using Cloud Radar Doppler Moments. Part II: Climatology  

Science Conference Proceedings (OSTI)

The algorithm described in Part I has been applied to the millimeter cloud radar observations from January 1999 to December 2005 at the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) and Tropical Western Pacific (...

Min Deng; Gerald G. Mace

2008-12-01T23:59:59.000Z

114

Retrieval of Cirrus Cloud Radiative and Backscattering Properties Using Combined Lidar and Infrared Radiometer (LIRAD) Measurements  

Science Conference Proceedings (OSTI)

A method for retrieval of cirrus macrophysical and radiative properties using combined ruby lidar and infrared radiometer measurements is explained in detail. The retrieval algorithm includes estimation of a variable backscatter-to-extinction ...

Jennifer M. Comstock; Kenneth Sassen

2001-10-01T23:59:59.000Z

115

Association of Tropical Cirrus in the 10–15-km Layer with Deep Convective Sources: An Observational Study Combining Millimeter Radar Data and Satellite-Derived Trajectories  

Science Conference Proceedings (OSTI)

In this paper, millimeter cloud radar (MMCR) and Geosynchronous Meteorological Satellite (GMS) data are combined to study the properties of tropical cirrus that are common in the 10–15-km layer of the tropical troposphere in the western Pacific. ...

Gerald G. Mace; Min Deng; Brian Soden; Ed Zipser

2006-02-01T23:59:59.000Z

116

Cirrus Parcel Model Comparison Project. Phase 1: The Critical Components to Simulate Cirrus Initiation Explicitly  

Science Conference Proceedings (OSTI)

The Cirrus Parcel Model Comparison Project, a project of the GCSS [Global Energy and Water Cycle Experiment (GEWEX) Cloud System Studies] Working Group on Cirrus Cloud Systems, involves the systematic comparison of current models of ice crystal ...

Ruei-Fong Lin; David O'C. Starr; Paul J. DeMott; Richard Cotton; Kenneth Sassen; Eric Jensen; Bernd Kärcher; Xiaohong Liu

2002-08-01T23:59:59.000Z

117

Spectral Reflectance and Atmospheric Energetics in Cirrus-like Clouds. Part II: Applications of a Fourier-Riccati Approach to Radiative Transfer  

Science Conference Proceedings (OSTI)

One of the major sources of uncertainty in climate studies is the detection of cirrus clouds and characterization of their radiative properties. Combinations of water vapor absorption channels (e.g., 1.38 µm), ice-water absorption channels (e.g., ...

Si-Chee Tsay; Philip M. Gabriel; Michael D. King; Graeme L. Stephens

1996-12-01T23:59:59.000Z

118

Relationship between Ice Water Path and Downward Longwave Radiation for Clouds Optically Thin in the Infrared: Observations and Model Calculations  

Science Conference Proceedings (OSTI)

A vertically pointing 3.2-cm radar is used to observe altostratus and cirrus clouds as they pass overhead. Radar reflectivities are used in combination with an empirical Zi-IWC (ice water content) relationship developed by Sassen (1987) to ...

Taneil Uttal; Sergey Y. Matrosov; Jack B. Snider; Robert A. Kropfli

1994-03-01T23:59:59.000Z

119

Near-Global Observations of Low Clouds  

Science Conference Proceedings (OSTI)

This paper analyzes several near-global datasets of low cloud cover, including the the International Satellite Cloud Climatology Project (ISCCP) satellite observations, C. J. Hahn et al. surface-derived observations, and the National Centers for ...

Bryan C. Weare

2000-04-01T23:59:59.000Z

120

Small Particles in Cirrus  

NLE Websites -- All DOE Office Websites (Extended Search)

Particles in Cirrus Particles in Cirrus Because the reflective properties of ice crystals in cirrus clouds can greatly influence the amount of solar energy that reaches the Earth, scientists use information about the shape and size of ice crystals as input to climate models. These data are obtained by satellite instruments, ground-based sensors, and research aircraft equipped with probes. However, notable discrepancies among these measurements have led to considerable uncertainty in how to represent these properties in climate models. From December 2009 through April 2010, the Atmospheric Radiation Measurement (ARM) Climate Research Facility will sponsor the use of an instrumented aircraft to obtain the most comprehensive set of measurements of ice crystals in cirrus clouds yet obtained. In conjunction with

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Water Vapor, Condensed Water, and Crystal Concentration in Orographically Influenced Cirrus Clouds  

Science Conference Proceedings (OSTI)

Results are presented from measurements made with a counterflow virtual impactor (CVI) in cirriform clouds containing crystals with dimensions typically less than 30 ?m. Independent measurements of crystal number concentration and cloud water ...

Johan Ström; Jost Heintzenberg

1994-08-01T23:59:59.000Z

122

Gazing at Cirrus Clouds for 25 Years through a Split Window. Part I: Methodology  

Science Conference Proceedings (OSTI)

This paper demonstrates that the split-window approach for estimating cloud properties can improve upon the methods commonly used for generating cloud temperature and emissivity climatologies from satellite imagers. Because the split-window ...

Andrew K. Heidinger; Michael J. Pavolonis

2009-06-01T23:59:59.000Z

123

Application of AVHRR/3 Imagery for the Improved Detection of Thin Cirrus Clouds and Specification of Cloud-Top Phase  

Science Conference Proceedings (OSTI)

A multisensor, data fusion technique has been developed that merges the spectral signatures of ice and water clouds in Advanced Very High Resolution Radiometer (AVHRR) imagery with cloud-top pressure analyses derived from the High-Resolution ...

Keith D. Hutchison

1999-12-01T23:59:59.000Z

124

Parameterization of Ice Cloud Radiative Properties and Its Application to the Potential Climatic Importance of Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

It is often assumed, in modeling and radiation budget simulation, that clouds below the cirrus level are entirely in the liquid phase. There is substantive evidence from observations that low and middle clouds are often of mixed phase. Using a ...

Zhian Sun; Keith P. Shine

1995-07-01T23:59:59.000Z

125

Diurnal effects in the composition of cirrus clouds Kenneth Sassen,1  

E-Print Network (OSTI)

measurements discriminate cloud phase and yield indications of ice particle shape and orientation [Sassen 2003; published 30 May 2003. [1] Extended (7-y) polarization lidar data, which are sensitive to ice parameterizations that treat the diurnal frequen- cies of some obvious cloud candidates such as cumulo- nimbus

Liou, K. N.

126

Development and Test of a Cirrus Parameterization Scheme Using NCAR CCM3  

Science Conference Proceedings (OSTI)

Recent research has shown that depending on the cloud properties, cirrus clouds can either increase or decrease the overall heating of the earth–atmosphere system. Hence, the representation of cirrus clouds in GCMs is recognized as an important ...

Dan?e Zurovac-Jevti?; Guang J. Zhang

2003-06-01T23:59:59.000Z

127

A GCM Parameterization of Ice Particle Mean Effective Sizes for High Latitude Cirrus Clouds and It's Comparison with Mid-Latitude Parmaterization  

NLE Websites -- All DOE Office Websites (Extended Search)

GCM Parameterization of Ice Particle Mean Effective GCM Parameterization of Ice Particle Mean Effective Sizes for High Latitude Cirrus Clouds and It's Comparison with Mid-Latitude Parameterization F. S. Boudala Department of Oceanography Dalhousie University Halifax, Nova Scotia, Canada Q. Fu Department of Atmospheric Sciences University of Washington Seattle, Washington G. A. Issac Meteorological Service of Canada Toronto, Ontario, Canada Introduction Single-scattering properties of ice clouds depend on both ice water content (IWC) and effective size of cloud particles (Fu 1996; Fu et al. 1998). However, only the IWC information is provided in numerical models. Stephens et al. (1990) showed that the ice cloud feedback on a CO 2 warming simulation could be either positive or negative depending on the value of the ice particle size assumed. Parameterizations

128

Cirrus Cloud Properties Derived from POLDER-1/ADEOS Polarized Radiances: First Validation Using a Ground-Based Lidar Network  

Science Conference Proceedings (OSTI)

Bidirectional polarized reflectances measured with the POLDER-1 instrument on board Advanced Earth Observing Satellite-1 have been used to infer cloud altitude and thermodynamical phase (ice/liquid) at a global scale. This paper presents a ...

Hélčne Chepfer; Philippe Goloub; James Spinhirne; Pierre H. Flamant; Mario Lavorato; Laurent Sauvage; Gérard Brogniez; Jacques Pelon

2000-02-01T23:59:59.000Z

129

Surface Temperature Related Variations in Tropical Cirrus Cloud as Measured by SAGE II  

Science Conference Proceedings (OSTI)

Data from the Stratospheric Aerosol and Gas Experiment II (SAGE II) solar occultation satellite instrument have been used to study the properties of tropical cloud over the altitude range 10.5–18.5 km. By virtue of its limb viewing measurement ...

G. S. Kent; E. R. Williams; P-H. Wang; M. P. McCormick; K. M. Skeens

1995-11-01T23:59:59.000Z

130

A Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Composite and Microphysical Study of Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site J. M. Haynes and G. L. Stephens Department of Atmospheric Science Colorado State University Fort Collins, Colorado Introduction Cirrus are known to play an important role in the radiative budget of the earth-atmosphere system. Previous studies have shown that cirrus within strong jet streams account for about 40% to 60% of all cirrus observed in the continental United States during the winter (Menzel et al. 1992). However, the connection between the properties of mid-latitude cirrus clouds and the large-scale flow that supports them is still, to a large degree, unknown. This study seeks to better quantify and understand this relationship through two interrelated investigations.

131

Midlatitude Cirrus Clouds Derived from Hurricane Nora: A Case Study with Implications for Ice Crystal Nucleation and Shape  

Science Conference Proceedings (OSTI)

Hurricane Nora traveled up the Baja Peninsula coast in the unusually warm El Nińo waters of September 1997 until rapidly decaying as it approached southern California on 24 September. The anvil cirrus blowoff from the final surge of tropical ...

Kenneth Sassen; W. Patrick Arnott; David O'C. Starr; Gerald G. Mace; Zhien Wang; Michael R. Poellot

2003-04-01T23:59:59.000Z

132

Removal of the Solar Component in AVHRR 3.7-µm Radiances for the Retrieval of Cirrus Cloud Parameters  

Science Conference Proceedings (OSTI)

A numerical scheme has been developed to remove the solar component in the Advanced Very High Resolution Radiometer (AVHRR) 3.7-µm channel for the retrieval of cirrus parameters during daytime. This method uses a number of prescribed threshold ...

N. X. Rao; S. C. Ou; K. N. Liou

1995-02-01T23:59:59.000Z

133

Marine Stratocumulus Cloud Fields off the Coast of Southern California Observed Using LANDSAT Imagery. Part II: Textural Analysis  

Science Conference Proceedings (OSTI)

Statistical measures of the spatial distributions of gray levels (cloud reflectivities) are determined for LANDSAT Multispectral Scanner digital data. Textural properties for twelve stratocumulus cloud fields, seven cumulus fields, and two cirrus ...

R. M. Welch; S. K. Sengupta; K. S. Kuo

1988-04-01T23:59:59.000Z

134

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

E-Print Network (OSTI)

Ice clouds occur quite frequently, yet so much about these clouds is unknown. In recent years, numerous investigations and field campaigns have been focused on the study of ice clouds, all with the ultimate goal of gaining a better understanding of microphysical and optical properties, as well as determining the radiative impact. Perhaps one of the most recognized instruments used for such research is the Moderate-resolution Imaging Spectroradiometer (MODIS), carried aboard the NASA EOS satellites Terra and Aqua. The present research aims to support ongoing efforts in the field of ice cloud research by use of observations obtained from Terra and Aqua MODIS. First, a technique is developed to infer ice cloud optical depth from the MODIS cirrus reflectance parameter. This technique is based on a previous method developed by Meyer et al. (2004). The applicability of the algorithm is demonstrated with retrievals from level-2 and -3 MODIS data. The technique is also evaluated with the operational MODIS cloud retrieval product and a method based on airborne ice cloud observations. From this technique, an archive of daily optical depth retrievals is constructed. Using simple statistics, the global spatial and temporal distributions of ice clouds are determined. Research has found that Aqua MODIS observes more frequent ice clouds and larger optical depths and ice water paths than does Terra MODIS. Finally, an analysis of the time series of daily optical depth values revealed that ice clouds at high latitudes, which are most likely associated with synoptic scale weather sytems, persist long enough to move with the upper level winds. Tropical ice clouds, however, dissipate more rapidly, and are in all likelihood associated with deep convective cells.

Meyer, Kerry Glynne

2007-08-01T23:59:59.000Z

135

Molecular Hydrogen in Infrared Cirrus  

E-Print Network (OSTI)

We combine data from our recent FUSE survey of interstellar molecular hydrogen absorption toward 50 high-latitude AGN with COBE-corrected IRAS 100 micron emission maps to study the correlation of infrared cirrus with H2. A plot of the H2 column density vs. IR cirrus intensity shows the same transition in molecular fraction, f_H2, as seen with total hydrogen column density, N_H. This transition is usually attributed to H2 self-shielding, and it suggests that many diffuse cirrus clouds contain H2 in significant fractions, f_H2 = 1-30%. These clouds cover approximately 50% of the northern sky at latitudes b > 30 degrees, at temperature-corrected 100 micron intensities D_100 > 1.5 MJy/sr. The sheetlike cirrus clouds, with hydrogen densities n_H > 30 cm^-3, may be compressed by dynamical processes at the disk-halo interface, and they are conducive to H2 formation on grain surfaces. Exploiting the correlation between N(H2) and 100 micron intensity, we estimate that cirrus clouds at b > 30 contain approximately 3000 M_sun in H2. Extrapolated over the inner Milky Way, the cirrus may contain 10^7 M_sun of H2 and 10^8 M_sun in total gas mass. If elevated to 100 pc, their gravitational potential energy is ~10^53 erg.

Kristen Gillmon; J. Michael Shull

2005-07-25T23:59:59.000Z

136

The Size Distribution and Mass-Weighted Terminal Velocity of Low-Latitude Tropopause Cirrus Crystal Populations  

Science Conference Proceedings (OSTI)

Ice crystal terminal velocities govern the lifetime of radiatively complex, climatologically important, low-latitude tropopause cirrus clouds. To better understand cloud lifetimes, the terminal velocities of low-latitude tropopause cirrus cloud ...

C. G. Schmitt; A. J. Heymsfield

2009-07-01T23:59:59.000Z

137

Analysis of the Tropical Tropopause Layer Cirrus in CALIPSO and MLS Data - A Water Perspective  

E-Print Network (OSTI)

Two mechanisms appear to be primarily responsible for the formation of cirrus clouds in Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. Here we propose to identify TTL cirrus clouds by analyzing water content measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Aura Microwave Limb Sounder (MLS). Using ice water content (IWC) and water vapor (H2O) abundances we identify TTL cirrus clouds that contain too much ice to have been formed in situ — and therefore must be of convective origin. We use two methods to infer amounts of water vapor available for in situ formation. Clouds with IWC greater than this threshold are categorized as being of convective origin; clouds with IWC below the threshold are ambiguous — they could either form from in situ or still be of convective origin. Applying the thresholds from December 2008 to November 2009, we found that at least 19.2% of tropical cirrus were definitively of convective origin at the tropopause (375 K) during boreal winter. At each level, we found three maxima in the occurrence of convective cirrus: western Pacific, equatorial Africa, and South America. Averaged over the entire tropics (30oS to 30oN), we found convective cirrus occurs more frequently in boreal winter and less frequently in boreal summer, basically following the a decreasing trend from DJF, MAM, SON, to JJA. During boreal summer, we found that only 4.6% of tropical cirrus come from convection. Sensitivity tests show that the thresholds derived at 390 K have the largest uncertainty. At lower levels, especially 375 K, our thresholds are robust.

Wang, Tao

2011-05-01T23:59:59.000Z

138

Selection of the 1.375-µm MODIS Channel for Remote Sensing of Cirrus Clouds and Stratospheric Aerosols from Space  

Science Conference Proceedings (OSTI)

Using spectral imaging data acquired with the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) from an ER-2 aircraft at 20-km altitude during the NASA FIRE Phase II Cirrus field program, it was found that narrow channels near the center of ...

Bo-Cai Gao; Yoram J. Kaufman

1995-12-01T23:59:59.000Z

139

Comparison of CALIPSO-Like, LaRC, and MODIS Retrievals of Ice-Cloud Properties over SIRTA in France and Florida during CRYSTAL-FACE  

Science Conference Proceedings (OSTI)

This study compares cirrus-cloud properties and, in particular, particle effective radius retrieved by a Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)-like method with two similar methods using Moderate-Resolution ...

M. Chiriaco; H. Chepfer; P. Minnis; M. Haeffelin; S. Platnick; D. Baumgardner; P. Dubuisson; M. McGill; V. Noël; J. Pelon; D. Spangenberg; S. Sun-Mack; G. Wind

2007-03-01T23:59:59.000Z

140

Observations of Liquid Water in Orographic Clouds over Elk Mountain  

Science Conference Proceedings (OSTI)

The relatively simple orographic clouds forming in winter over Elk Mountain, Wyoming provided useful opportunities for field studies of cloud formation and of ice crystal development. In this paper, the observations of cloud droplet populations ...

Marcia K. Politovich; Gabor Vali

1983-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Cloud Top Liquid Water from Lidar Observations of Marine Stratocumulus  

Science Conference Proceedings (OSTI)

Maine stratus clouds were simultaneously observed by nadir Nd:YAG lidar measurements and in situ cloud physics measurements. A procedure was applied to derive the two-dimensional vertical cross section of the liquid water from within the cloud ...

J. D. Spinhirne; R. Boers; W. D. Hart

1989-02-01T23:59:59.000Z

142

ARM - Publications: Science Team Meeting Documents: Cirrus properties and  

NLE Websites -- All DOE Office Websites (Extended Search)

Cirrus properties and air mean vertical motion retrieval using Cirrus properties and air mean vertical motion retrieval using mm-wavelength Doppler radar moments Deng, Min University of Utah Mace, Gerald University of Utah Vertically pointing millimeter wavelength Doppler radar provides valuable information on upper tropospheric cloud properties and dynamics. We are developing an innovative algorithm to simultaneously retrieve cirrus microphysical parameters and air mean vertical motion by using the three moments of the Doppler spectrum. The technique utilizes a statement that the observed Doppler spectrum is the convolution of a quiet air reflectivity spectrum with the turbulence PDF (probability density function). The set of equations describing the Doppler spectrum moments are inverted using optimal estimation theory to derive estimates of the

143

ISCCP Cloud Properties Associated with Standard Cloud Types Identified in Individual Surface Observations  

Science Conference Proceedings (OSTI)

Individual surface weather observations from land stations and ships are compared with individual cloud retrievals of the International Satellite Cloud Climatology Project (ISCCP), stage C1, for an 8-yr period (1983–91) to relate cloud optical ...

Carole J. Hahn; William B. Rossow; Stephen G. Warren

2001-01-01T23:59:59.000Z

144

Observed Relationships between Arctic Longwave Cloud Forcing and Cloud Parameters Using a Neural Network  

Science Conference Proceedings (OSTI)

A neural network technique is used to quantify relationships involved in cloud–radiation feedbacks based on observations from the Surface Heat Budget of the Arctic (SHEBA) project. Sensitivities of longwave cloud forcing (CFL) to cloud parameters ...

Yonghua Chen; Filipe Aires; Jennifer A. Francis; James R. Miller

2006-08-01T23:59:59.000Z

145

More Observations of Small Funnel Clouds and Other Tubular Clouds  

Science Conference Proceedings (OSTI)

In this brief contribution, photographic documentation is provided of a variety of small, tubular-shaped clouds and of a small funnel cloud pendant from a convective cloud that appears to have been modified by flow over high-altitude mountains in ...

Howard B. Bluestein

2005-12-01T23:59:59.000Z

146

Observations of Cloud-Top Entrainment in Marine Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

Measurements of the thermodynamic and dynamic properties of entrainment events in marine stratocumulus are used to explain why cloud-top entrainment instability may not lead to the breakup of the clouds and to define the role of cloud-top ...

Qing Wang; Bruce A. Albrecht

1994-06-01T23:59:59.000Z

147

A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part I: Macrophysical and Synoptic Properties  

Science Conference Proceedings (OSTI)

A uniquely extensive high cloud dataset has been collected from the University of Utah Facility for Atmospheric Remote Sensing in support of the First (ISCCP) International Satellite Cloud Climatology Project Regional Experiment extended time ...

Kenneth Sassen; James R. Campbell

2001-03-01T23:59:59.000Z

148

Variations in Cloud Cover and Cloud Types over the Ocean from Surface Observations, 1954–2008  

Science Conference Proceedings (OSTI)

Synoptic weather observations from ships throughout the World Ocean have been analyzed to produce a climatology of total cloud cover and the amounts of nine cloud types. About 54 million observations contributed to the climatology, which now ...

Ryan Eastman; Stephen G. Warren; Carole J. Hahn

2011-11-01T23:59:59.000Z

149

The Mesoscale Dynamics of Thin Tropical Tropopause Cirrus  

Science Conference Proceedings (OSTI)

Thin cirrus clouds in the tropical tropopause layer (TTL) are warmed through the absorption of infrared radiation. The response of the cloud and the surrounding atmosphere to this thermal forcing is investigated through linear theory and ...

Dale R. Durran; Tra Dinh; Marie Ammerman; Thomas Ackerman

2009-09-01T23:59:59.000Z

150

Estimation of Cirrus Optical Thickness from Sun Photometer Measurements  

Science Conference Proceedings (OSTI)

A method is proposed to estimate the optical thickness of cirrus clouds from ground-based sun photometry. Transfer calculations of solar radiation in ice clouds were made by the Monte Carlo method. A scattering phase function presented by Takano ...

Masataka Shiobara; Shoji Asano

1994-06-01T23:59:59.000Z

151

Comparison of Cirrus Height and Optical Depth Derived from Satellite and Aircraft Measurements  

Science Conference Proceedings (OSTI)

During the International Cirrus Experiment (ICE'89) simultaneous measurements of Cirrus cloud-top height and optical depth by satellite and aircraft have been taken. Data from the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA ...

M. Kästner; K. T. Kriebel; R. Meerkötter; W. Renger; G. H. Ruppersberg; P. Wendling

1993-10-01T23:59:59.000Z

152

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

Science Conference Proceedings (OSTI)

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

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

2012-09-06T23:59:59.000Z

153

Automatic Cloud Tracking Applied to GOES and METEOSAT Observations  

Science Conference Proceedings (OSTI)

Improvements to the SRI automatic cloud-tracking system are described that enable it to operate on multilayer clouds associated with severe storms. The improved method has been tested using rapid-scan observations of Hurricane Eloise obtained by ...

Roy M. Endlich; Daniel E. Wolf

1981-03-01T23:59:59.000Z

154

Combined Satellite- and Surface-Based Observations of Clouds  

Science Conference Proceedings (OSTI)

A new method for combining satellite and surface-based cloud observations into a self-consistent three-dimensional field is presented. This method derives the probabilities of the cloud states, which are most consistent with all of the ...

Bryan C. Weare

1999-03-01T23:59:59.000Z

155

Longwave Cloud Radiative Forcing as Determined from Nimbus-7 Observations  

Science Conference Proceedings (OSTI)

Collocated and coincident cloud and outgoing longwave radiation observations taken by experiments on board the Nimbus-7 satellite have been used to infer the daytime longwave cloud-radiative forcing. Through the specification of a time-series of ...

Philip E. Ardanuy; Larry L. Stowe; Arnold Gruber; Mitchell Weiss; Craig S. Long

1989-08-01T23:59:59.000Z

156

Aircraft Observations of Ice Crystal Evolution in an Altostratus Cloud  

Science Conference Proceedings (OSTI)

Observations from a Lagrangian spiral descent within altostratus cloud associated with a cold front were used to study the evolution of ice particle spectra by following populations of ice crystals as they fell through the cloud. The flight track ...

Paul R. Field

1999-06-01T23:59:59.000Z

157

Relating Satellite-Observed Cloud Properties from MODIS to Meteorological Conditions for Marine Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

This study examines 6 yr of cloud properties observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA Terra satellite in five prominent marine boundary layer (MBL) cloud regions (California, Peru, Canary, Angola, ...

Guang J. Zhang; Andrew M. Vogelmann; Michael P. Jensen; William D. Collins; Edward P. Luke

2010-03-01T23:59:59.000Z

158

Properties of Tropical Cloud Ensembles Estimated Using a Cloud Model and an Observed Updraft Population  

Science Conference Proceedings (OSTI)

A simple cloud model is developed which is designed for both diagnostic studies and mesoscale cumulus parameterization experiments. The cloud model is combined with an observed population of tropical convective updrafts and used to examine the ...

William M. Frank; Charles Cohen

1985-09-01T23:59:59.000Z

159

Isentropic modeling of a cirrus cloud event observed in the midlatitude upper troposphere and lower stratosphere  

E-Print Network (OSTI)

´so-e´chelle de l'Ozone Stratosphe´rique par Advection (MIMOSA) model to take into account the three phases for fall speeds around 1 cm/s and gives ice water content around 3­4 mg/m3 . Fall speed is also a critical parameter, and a better parameterization with altitude or other atmospheric conditions in the modeling

Brogniez, Hélène

160

Observations of chemical differentiation in clumpy molecular clouds  

E-Print Network (OSTI)

We have extensively mapped a sample of dense molecular clouds (L1512, TMC-1C, L1262, Per 7, L1389, L1251E) in lines of HC3N, CH3OH, SO and C^{18}O. We demonstrate that a high degree of chemical differentiation is present in all of the observed clouds. We analyse the molecular maps for each cloud, demonstrating a systematic chemical differentiation across the sample, which we relate to the evolutionary state of the cloud. We relate our observations to the cloud physical, kinematical and evolutionary properties, and also compare them to the predictions of simple chemical models. The implications of this work for understanding the origin of the clumpy structures and chemical differentiation observed in dense clouds are discussed.

J. V. Buckle; S. D. Rodgers; E. S. Wirström; S. B. Charnley; A. J. Markwick-Kemper; H. M. Butner; S. Takakuwa

2007-04-09T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The Development of Midlatitude Cirrus Models for MODIS Using FIRE-I, FIRE-II, and ARM In Situ Data  

Science Conference Proceedings (OSTI)

Detailed in situ data from cirrus clouds have been collected during dedicated field campaigns, but the use of the size and habit distribution data has been lagging in the development of more realistic cirrus scattering models. In this study, the ...

Shaima L. Nasiri; Bryan A. Baum; Andrew J. Heymsfield; Ping Yang; Michael R. Poellot; David P. Kratz; Yongxiang Hu

2002-03-01T23:59:59.000Z

162

Observations of Marine Stratocumulus Clouds During FIRE  

Science Conference Proceedings (OSTI)

During June and July 1987, a major collaborative experiment (part of The First ISCCP [International Satellite Cloud Climatology Project] Regional Experiment (FIRE) took place off the coast of California to study the extensive fields of ...

Bruce A. Albrecht; David A. Randall; Stephen Nicholls

1988-06-01T23:59:59.000Z

163

Estimating Cloud Type from Pyranometer Observations  

Science Conference Proceedings (OSTI)

In this paper the authors evaluate an inexpensive and automatable method to estimate cloud type at a given location during daylight hours using the time series of irradiance from a pyranometer. The motivation for this investigation is to provide ...

Claude E. Duchon; Mark S. O’Malley

1999-01-01T23:59:59.000Z

164

Cirriform Rotor Cloud Observed on a Canadian Arctic Ice Cap  

Science Conference Proceedings (OSTI)

A thin rotor cloud was observed on the lee side of Penny Ice Cap in the Canadian Arctic on 21 April 1996. The cloud consisted of thin cirriform layers, so that its motion was clearly observed. By means of time-lapse camera photography, the ...

Hisashi Ozawa; Kumiko Goto-Azuma; Koyuru Iwanami; Roy M. Koerner

1998-06-01T23:59:59.000Z

165

Examination of Coupling between an Upper-Tropospheric Cloud System and Synoptic-Scale Dynamics Diagnosed from Wind Profiler and Radiosonde Data  

Science Conference Proceedings (OSTI)

The evolution of synoptic-scale dynamics associated with a middle and upper tropospheric cloud event that occurred on 26 November 1991 is examined. The case under consideration occurred during the FIRE Cirrus-II Intensive Field Observing Period ...

Gerald G. Mace; David O'C. Starr; Thomas P. Ackerman; Patrick Minnis

1995-12-01T23:59:59.000Z

166

Radiosonde observations at Pt. Reyes and cloud properties retrieved from  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiosonde observations at Pt. Reyes and cloud properties retrieved from Radiosonde observations at Pt. Reyes and cloud properties retrieved from GOES-WEST Inoue, Toshiro MRI/JMA Category: Field Campaigns Low-level cloud formed off the west coast of continents plays an important role in general circulation and climate. Marine Stratus Radiation Aerosol and Drizzle (MASRAD) was conducted at the ARM mobile site deployed at Pt Reyes, California during April to September. Here, we studied the relationship between meteorological parameters observed by GPS sonde and cloud properties observed from GOES-WEST during the MASRAD intensive operational period. Cloud properties are retrieved from VISST (Visible Infrared Solar-infrared Split window Technique). The vertical profile of stability, relative humidity (RH) and wind speed observed by GPS sonde are

167

Climatological Data for Clouds Over the Globe from Surface Observations  

NLE Websites -- All DOE Office Websites (Extended Search)

for Clouds Over the Globe from Surface Observations for Clouds Over the Globe from Surface Observations (1988) (NDP-026) DOI: 10.3334/CDIAC/cli.ndp026 data Data Investigators C. J. Hahn, S. G. Warren, J. London, R. L. Jenne, and R. M. Chervin With some data from as early as 1930, global long-term monthly and/or seasonal total cloud cover, cloud type amounts and frequencies of occurrence, low cloud base heights, harmonic analyses of annual and diurnal cycles, interannual variations and trends, and cloud type co-occurrences have been compiled and presented in two atlases (Warren et al. 1988, 1990). These data were derived from land and ship synoptic weather reports from the "SPOT" archive of the Fleet Numerical Oceanography Center (FNOC) and from Release 1 of the Comprehensive Ocean-Atmosphere Data Set (COADS) for

168

The Effect of Clouds on Air Showers Observation from Space  

E-Print Network (OSTI)

Issues relating to extensive air showers observation by a space-borne fluorescence detector and the effects of clouds on the observations are investigated using Monte Carlo simulation. The simulations assume the presence of clouds with varying altitudes and optical depths. Simulated events are reconstructed assuming a cloud-free atmosphere. While it is anticipated that auxiliary instruments, such as LIDAR (LIght Detection And Ranging), will be employed to measure the atmospheric conditions during actual observation, it is still possible that these instruments may fail to recognize the presence of a cloud in a particular shower observation. The purpose of this study is to investigate the effects on the reconstructed shower parameters in such cases. Reconstruction results are shown for both monocular and stereo detectors and for the two limiting cases of optically thin, and optically thick clouds.

T. Abu-Zayyad; C. C. H. Jui; E. C. Loh

2003-10-28T23:59:59.000Z

169

Satellite Observations of Variations in Tropical Cyclone Convection Caused by Upper-Tropospheric Troughs  

Science Conference Proceedings (OSTI)

The mutual adjustment between upper-tropospheric troughs and the structure of western Atlantic Tropical Cyclones Florence (1988) and Irene (1981) are analyzed using satellite and in situ data. Satellite-observed tracers (e.g., cirrus clouds, ...

Edward B. Rodgers; Simon W. Chang; John Stout; Joseph Steranka; Jainn-Jong Shi

1991-08-01T23:59:59.000Z

170

Observations of the Interaction between Cumulus Clouds and Warm Stratocumulus Clouds in the Marine Boundary Layer during ASTEX  

Science Conference Proceedings (OSTI)

Decoupling of the marine boundary layer beneath stratocumulus clouds and the formation of cumulus clouds at the top of a surface-based mixed layer (SML) have frequently been observed and modeled. When such cumulus clouds penetrate the overlying ...

G. M. Martin; D. W. Johnson; D. P. Rogers; P. R. Jonas; P. Minnis; D. A. Hegg

1995-08-01T23:59:59.000Z

171

SPARTICUS: Small Particles in Cirrus Science and Operations Plan  

SciTech Connect

From a mass-weighted perspective, cirrus clouds exert an enormous influence on the radiative energy budget of the earth’s climate system. Owing to their location in the cold upper troposphere, cirrus can significantly reduce the outgoing longwave radiation while, at the same time, remaining relatively transmissive to solar energy. Thus, cirrus clouds are the only cloud genre that can exert a direct radiative warming influence on the climate system (Ackerman et al. 1988). It is not surprising, therefore, that general circulation models (GCMs) are especially sensitive to the presence of cirrus in the model atmosphere. Lohmann and Roeckner (1995), for instance, show that the climate sensitivity can vary by as much as 40% due to the properties of cirrus varying between transparent and opaque limits. Lohmann and Roeckner (1995) also identify a key feedback by cirrus that is often overlooked; on longer time scales cloud heating in the upper troposphere can act to maintain and modulate the general circulation of the atmosphere through accelerating the subtropical and polar jet streams. Understanding these mechanisms and representing them in models is complicated by the fact that cirrus properties vary over an enormous dynamic range compared to most other clouds.

J Mace, E Jensen, G McFarquhar, J Comstock, T Ackerman, D Mitchell, X Liu, T Garrett

2009-10-31T23:59:59.000Z

172

Observed Microphysical Structure of Midlevel, Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

This paper analyzes airborne measurements of six midlevel clouds observed over the Great Plains of the United States in late 1999 and early 2000 during the fifth of the Complex Layered-Cloud Experiments (CLEX-5). Data show that these innocuous-...

Robert P. Fleishauer; Vincent E. Larson; Thomas H. Vonder Haar

2002-06-01T23:59:59.000Z

173

arm_stm_2008_borg_cirrus_poster.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Cirrus Cloud Characterization Cirrus Cloud Characterization with Raman Lidar Measurements at Southern Great Plains Lori Borg, David Turner, Robert Holz, David Tobin, Bob Knuteson, Leslie Moy, Daniel DeSlover, Ed Eloranta, Hank Revercomb (PI) Altitude [km] Radar + Lidar Heating Rate [deg/day] Altitude [km] Radar Heating Rate [deg/day] Altitude [km] MMCR Radar Reflectivity [dBZ] (color) with Lidar Boundaries (black) SGP Cirrus Case Study: 11/08/2005 18:00UTC - 11/11/2005 12:00 UTC Lori Borg, lori.borg@ssec.wisc.edu Introduction: Cirrus clouds play a significant role in the energy budget of the atmosphere and represent a major source of uncertainly in understanding climate and climate change. A large part of this uncertainty lies in the modeling of the cloud, which requires assumptions and

174

Thunderstorm Cloud Top Observations Using Satellite Stereoscopy  

Science Conference Proceedings (OSTI)

GOES stereoscopy is applied to the study of severe squall line cells. Short interval (3 min) GOES stereoscopic data from the 2–3 May 1979 SESAME case were used to measure cloud top heights of growing storms as a function of time. A one-...

Robert A. Mack; A. F. Hasler; Robert F. Adler

1983-10-01T23:59:59.000Z

175

A 94-GHz Doppler Radar for Cloud Observations  

Science Conference Proceedings (OSTI)

A Doppler radar operating at 3.2 mm wavelength was designed and assembled primarily for observation of clouds and precipitation. Phase detection of the radar signals which is required for Doppler operation is implemented through the use of a ...

Roger Lhermitte

1987-03-01T23:59:59.000Z

176

Observations of a Cloud Are Triggered by Thunderstorm Outflow  

Science Conference Proceedings (OSTI)

This paper presents aircraft, radar, satellite and rawinsonde observations which describe a cloud am formed by moist downdraft outflow from a cumulonimbus cluster in northwest Kansas. Aircraft cross sections are presented of four variables at 160 ...

David A. Matthews

1981-10-01T23:59:59.000Z

177

Combined System for Observations of Tropospheric and Stratospheric Thin Clouds  

Science Conference Proceedings (OSTI)

A balloonborne sonde and a polarization lidar have been developed to make combined observations of thin tropospheric and stratospheric clouds. In their first application these instruments have been used in a campaign organized to study Antarctic ...

A. Adriani; G. P. Gobbi; M. Viterbini; S. Ugazio

1993-02-01T23:59:59.000Z

178

Comparison of Cloud Cover from All-Sky Imager and Meteorological Observer  

Science Conference Proceedings (OSTI)

Naked-eye observation of cloud cover has widely resisted automation. Replacement of human observation by instruments is an inexorable trend for the development of ground-based macroscopic cloud observation. In this paper, cloud covers from an all-...

Juan Huo; Daren Lu

2012-08-01T23:59:59.000Z

179

Climatological Data For Clouds Over the Globe From Surface Observations,  

NLE Websites -- All DOE Office Websites (Extended Search)

For Clouds Over the Globe From Surface Observations, For Clouds Over the Globe From Surface Observations, 1982-1991: The Total Cloud Edition (1994) (NDP-026a) data Data Investigators C. J. Hahn, S. G. Warren, and J. London Routine, synoptic surface weather reports from ships and land stations over the entire globe, for the10-year period December 1981 through November 1991, were processed for total cloud cover and the frequencies of occurrence of clear sky, sky-obscured due to precipitation, and sky-obscured due to fog. Archived data, consisting of various annual, seasonal and monthly averages, are provided in grid boxes that are typically 2.5° × 2.5° for land and 5° × 5° for ocean. Day and nighttime averages are also given separately for each season. Several derived quantities, such as interannual variations and annual and diurnal

180

Cloud-state-dependent Sampling in AIRS Observations based on CloudSat Cloud Classification  

Science Conference Proceedings (OSTI)

The precision, accuracy, and potential sampling biases of temperature (T) and water vapor (q) vertical profiles obtained by satellite infrared sounding instruments are highly cloud-state dependent and poorly quantified. We describe progress ...

Qing Yue; Eric J. Fetzer; Brian H. Kahn; Sun Wong; Gerald Manipon; Alexandre Guillaume; Brian Wilson

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Impact of Ice Crystal Roughness on Satellite Retrieved Cloud Properties  

NLE Websites -- All DOE Office Websites (Extended Search)

Ice Crystal Roughness on Satellite Retrieved Cloud Properties Ice Crystal Roughness on Satellite Retrieved Cloud Properties P. Minnis 1 , P. W. Heck 2 , R. F. Arduini 3 , R. Palikonda 3 , J. K. Ayers 3 , M. M. Khaiyer 3 , P. Yang 4 , Y. Xie 4 3 Science Systems & Applications, Inc. Hampton, VA 1 NASA Langley Research Center Hampton, VA Current Cirrus Models Inadequate Cirrus cloud optical depths Ď„ (heights z e ) are often over (under) estimated when derived from solar reflectances. In situ data suggest smaller asymmetry factors, g, than used in most retrieval models. Multi-angle measurements point to smoother phase functions than for solid, smooth xtals. Calculations show that solid crystals with roughened facets or embedded bubbles --both observed in real cirrus particles-- yield smoother phase functions & smaller g

182

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

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Type Occurrences Cloud Type Occurrences and Radiative Forcings Simulated by a Cloud Resolving Model Using Observations from Satellite and Cloud Radar Y. Luo and S. K. Krueger University of Utah Salt Lake City, Utah Introduction Because of both the various effects clouds exert on the earth-atmospheric system and the cloud feedback, correct representations of clouds in numerical models are critical for accurate climate modeling and weather forecast. Unfortunately, determination of clouds and their radiative feedback processes is still the weakest component of current general circulation models (e.g., Senior and Mitchell 1993, Cess et al. 1996). Using radiative fluxes at the top of atmosphere (TOA) available from satellite observations made by the Earth Radiation Budget Experiment (ERBE; Barkstrom 1984), one could assess cloud radiative effects

183

Diagnosis of the Warm Rain Process in Cloud-Resolving Models Using Joint CloudSat and MODIS Observations  

Science Conference Proceedings (OSTI)

This study examines the warm rain formation process in global and regional cloud-resolving models. Methodologies developed to analyze CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations are employed to ...

Kentaroh Suzuki; Graeme L. Stephens; Susan C. van den Heever; Takashi Y. Nakajima

2011-11-01T23:59:59.000Z

184

Particle Growth and Drop Collection Efficiency of Warm Clouds as Inferred from Joint CloudSat and MODIS Observations  

Science Conference Proceedings (OSTI)

This study describes an approach for combining CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations to investigate the microphysical processes of warm clouds on the global scale. MODIS column optical thickness ...

Kentaroh Suzuki; Takashi Y. Nakajima; Graeme L. Stephens

2010-09-01T23:59:59.000Z

185

Cloud Diabatic Forcing of the Atmosphere, Estimated from Simultaneous ECMWF Diabatic Heating and ISCCP Cloud Amount Observations  

Science Conference Proceedings (OSTI)

The cloud diabatic forcing (CDF) of the atmosphere, defined as the difference between the diabatic heating in average and in clear-sky conditions is estimated from time series of simultaneous observations of diabatic heating and cloud amount. The ...

Peter Siegmund

1993-12-01T23:59:59.000Z

186

Preliminary Studies on the Variational Assimilation of Cloud-Radiation Observations Using ARM Observations  

NLE Websites -- All DOE Office Websites (Extended Search)

Studies on the Variational Assimilation Studies on the Variational Assimilation of Cloud-Radiation Observations Using ARM Observations M. Janisková, J.-F. Mahfouf, and J.-J. Morcrette European Centre for Medium-Range Weather Forecasts Shinfield Park, Reading Berskshire, United Kingdom Abstract A linearized cloud scheme and a radiation scheme including cloud effects have been developed at European Centre for Medium-Range Weather Forecasts (ECMWF) to assimilate cloud properties in the framework of the four-dimensional variational (4D-Var) assimilation system. To investigate the potential of those schemes to modify the model temperature, humidity and cloud profiles and produce a better match to the observed radiation fluxes, one-dimensional variational (1D-Var) assimilation experiments have been carried out using data from the Atmospheric Radiation Measurement (ARM)

187

Observational and Model Estimates of Cloud Amount Feedback over the Indian and Pacific Oceans  

Science Conference Proceedings (OSTI)

Constraining intermodel spread in cloud feedback with observations is problematic because available cloud datasets are affected by spurious behavior in long-term variability. This problem is addressed by examining cloud amount in three independent ...

Katinka Bellomo; Amy C. Clement; Joel R. Norris; Brian J. Soden

2014-01-01T23:59:59.000Z

188

The Effect of Cloud Sides on Reflected Solar Radiation as Deduced from Satellite Observations  

Science Conference Proceedings (OSTI)

We report the observation of a feature that is characteristic of the reflection of solar radiation from absorbing, finite clouds. When absorption takes place, more radiation can be reflected by broken cloud fields than by extensive unbroken cloud ...

James A. Coakley Jr.; Roger Davies

1986-05-01T23:59:59.000Z

189

An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds  

Science Conference Proceedings (OSTI)

The large horizontal extent, with its location in the cold upper troposphere, and ice composition make cirrus clouds important modulators of the Earth's radiation budget and climate. Cirrus cloud microphysical properties are difficult to measure ...

Jennifer M. Comstock; Sally A. McFarlane; Robert d'Entremont; Daniel DeSlover; David D. Turner; Gerald G. Mace; Sergey Y. Matrosov; Matthew D. Shupe; Patrick Minnis; David Mitchell; Kenneth Sassen; Zhien Wang

2007-02-01T23:59:59.000Z

190

HIGH-RESOLUTION CH OBSERVATIONS OF TWO TRANSLUCENT MOLECULAR CLOUDS  

SciTech Connect

We present high-resolution (1.'3 x 1.'6) observations of the CH {sup 2}{pi}{sub 1/2} (F = 1-1) emission line at 3335 MHz in two high-latitude translucent clouds, MBM 3 and 40. At the assumed cloud distances, the angular resolution corresponds to {approx}0.05 pc, nearly an order of magnitude better than previous studies. Comparisons of the CH emission with previously obtained CO(1-0) data are difficult to interpret: the CO and CH line emission correlates in MBM 40 but not in MBM 3. In both clouds, there is a spatial offset in the peak emission, and perhaps in velocity for MBM 40. The difference in emission characteristics for the two tracers are noticeable in these two nearby clouds because of the high spatial resolution. Since both CH and CO are deemed to be reliable tracers of H{sub 2}, our results indicate that more care should be taken when using one of these tracers to determine the mass of a nearby molecular cloud.

Chastain, Raymond J. [Department of Physics and Astronomy, Louisiana State University, 368 Nicholson Hall, Tower Dr. Baton Rouge, LA 70803 (United States); Cotten, David; Magnani, Loris [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States)

2010-01-15T23:59:59.000Z

191

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

E-Print Network (OSTI)

This research focuses on aircraft observational studies of aerosol-cloud interactions in cumulus clouds. The data were collected in the summer of 2004, the spring of 2007 and the mid-winter and spring of 2008 in Texas, central Saudi Arabia and Istanbul, Turkey, respectively. A set of 24 pairs of sub-cloud aerosol and cloud penetration data are analyzed. Measurements of fine and coarse mode aerosol concentrations from 3 different instruments were combined and fitted with lognormal distributions. The fit parameters of the lognormal distributions are compared with cloud droplet effective radii retrieved from 260 cloud penetrations. Cloud condensation nuclei (CCN) measurements for a subset of 10 cases from the Istanbul region are compared with concentrations predicted from aerosol size distributions. Ammonium sulfate was assumed to represent the soluble component of aerosol with dry sizes smaller than 0.5 mm and sodium chloride for aerosol larger than 0.5 mm. The measured CCN spectrum was used to estimate the soluble fraction. The correlations of the measured CCN concentration with the predicted CCN concentration were strong (R2 > 0.89) for supersaturations of 0.2, 0.3 and 0.6%. The measured concentrations were typically consistent with an aerosol having a soluble fraction between roughly 0.5 and 1.0, suggesting a contribution of sulfate or some other similarly soluble inorganic compound. The predicted CCN were found to vary by +or-3.7% when the soluble fraction was varied by 0.1. Cumulative aerosol concentrations at cutoff dry diameters of 1.1, 0.1 and 0.06 mm were found to be correlated with cloud condensation nuclei concentrations but not with maximum cloud base droplet concentrations. It is also shown that in some cases the predominant mechanisms involved in the formation of precipitation were altered and modified by the aerosol properties. This study suggests that CCN-forced variations in cloud droplet number concentration can change the effective radius profile and the type of precipitation hydrometeors. These differences may have a major impact on the global hydrological cycle and energy budget.

Axisa, Duncan

2009-12-01T23:59:59.000Z

192

Droplet Growth in Warm Water Clouds Observed by the A-Train. Part II: A Multisensor View  

Science Conference Proceedings (OSTI)

Hydrometeor droplet growth processes are inferred from a combination of Aqua/Moderate Resolution Imaging Spectroradiometer (MODIS) cloud particle size observations and CloudSat/Cloud Profiling Radar (CPR) observations of warm water clouds. This ...

Takashi Y. Nakajima; Kentaroh Suzuki; Graeme L. Stephens

2010-06-01T23:59:59.000Z

193

Cirrus Outflow Dynamics  

Science Conference Proceedings (OSTI)

Cirrus outflow from deep convection are analyzed as dynamically and thermodynamically active systems. The initial outflow is considered as an analog to wake collapse, in which a neutrally buoyant flow intrusion is flattened and stretched by its ...

Douglas K. Lilly

1988-05-01T23:59:59.000Z

194

Cirrus Crystal Terminal Velocities  

Science Conference Proceedings (OSTI)

Cirrus crystal terminal velocities are of primary importance in determining the rate of transport of condensate from upper- to middle-tropospheric levels and profoundly influence the earth’s radiation balance through their effect on the rate of ...

Andrew J. Heymsfield; Jean Iaquinta

2000-04-01T23:59:59.000Z

195

Estimating Three-Dimensional Cloud Structure via Statistically Blended Satellite Observations  

Science Conference Proceedings (OSTI)

The launch of the NASA CloudSat in April 2006 enabled the first satellite-based global observation of vertically-resolved cloud information. However, CloudSat’s non-scanning W-band (94 GHz) Cloud Profiling Radar (CPR) provides only a nadir cross-...

Steven D. Miller; John M. Forsythe; Philip T. Partain; John M. Haynes; Richard L. Bankert; Manajit Sengupta; Cristian Mitrescu; Jeffrey D. Hawkins; Thomas H. Vonder Haar

196

Observational Constraints on the Cloud Thermodynamic Phase in Midlatitude Storms CATHERINE M. NAUD  

E-Print Network (OSTI)

in the ice versus the liquid phase. Early prognostic cloud water parameterizations for stratiform clouds supercooled liquid water gradually gives way to ice in the mixed-phase regions of clouds are still poorlyObservational Constraints on the Cloud Thermodynamic Phase in Midlatitude Storms CATHERINE M. NAUD

197

Racoro Extended-Term Aircraft Observations of Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

A first-of-a-kind, extended-term cloud aircraft campaign was conducted to obtain an in situ statistical characterization of continental boundary layer clouds needed to investigate cloud processes and refine retrieval algorithms. Coordinated by the ...

Andrew M. Vogelmann; Greg M. McFarquhar; John A. Ogren; David D. Turner; Jennifer M. Comstock; Graham Feingold; Charles N. Long; Haflidi H. Jonsson; Anthony Bucholtz; Don R. Collins; Glenn S. Diskin; Hermann Gerber; R. Paul Lawson; Roy K. Woods; Elisabeth Andrews; Hee-Jung Yang; J. Christine Chiu; Daniel Hartsock; John M. Hubbe; Chaomei Lo; Alexander Marshak; Justin W. Monroe; Sally A. McFarlane; Beat Schmid; Jason M. Tomlinson; Tami Toto

2012-06-01T23:59:59.000Z

198

Aerosol Remote Sensing over Clouds Using A-Train Observations  

Science Conference Proceedings (OSTI)

The detection of aerosol above clouds is critical for the estimate of both the aerosol and cloud radiative impacts. In this study, the authors present a new method to retrieve the aerosol properties over clouds that uses the multiangle ...

F. Waquet; J. Riedi; L. C. Labonnote; P. Goloub; B. Cairns; J-L. Deuzé; D. Tanré

2009-08-01T23:59:59.000Z

199

Low Cloud Type over the Ocean from Surface Observations. Part II: Geographical and Seasonal Variations  

Science Conference Proceedings (OSTI)

Synoptic surface cloud observations primarily made by volunteer observing ships are used to construct global climatologies of the frequency of occurrence of individual low cloud types over the ocean for daytime during summer and winter seasons ...

Joel R. Norris

1998-03-01T23:59:59.000Z

200

Comparison of an Experimental NOAA AVHRR Cloud Dataset with Other Observed and Forecast Cloud Datasets  

Science Conference Proceedings (OSTI)

CLAVR [cloud from AVHRR (Advanced Very High Resolution Radiometer)] is a global cloud dataset under development at NOAA/NESDIS (National Environmental Satellite, Data, and Information Service). Total cloud amount from two experimental cases, 9 ...

Yu-Tai Hou; Kenneth A. Campana; Kenneth E. Mitchell; Shi-Keng Yang; Larry L. Stowe

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

An ARSCL-based cloud type climatology from retrievals and it...  

NLE Websites -- All DOE Office Websites (Extended Search)

but misses situations where cirrus clouds overlay low cloud layers. These are mostly prefrontal situations accompanied by mid-tropospheric subsidence and weak southerly winds...

202

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

SciTech Connect

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

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

2010-06-17T23:59:59.000Z

203

Ground-Based Remote Sensing of Cloud Particle Sizes during the 26 November 1991 FIRE II Cirrus Case: Comparisons with In Situ Data  

Science Conference Proceedings (OSTI)

The paper presents the results of retrieving characteristic particle sizes for the November 26 1991 FIRE II case using two methods that utilize ground-based remotes sensors. The size information for the complete vertical depth of the cloud was ...

S. Y. Matrosov; A. J. Heymsfield; J. M. Intrieri; B. W. Orr; J. B. Snider

1995-12-01T23:59:59.000Z

204

Interpretation of AIRS Data in Thin Cirrus Atmospheres Based on a Fast Radiative Transfer Model  

Science Conference Proceedings (OSTI)

A thin cirrus cloud thermal infrared radiative transfer model has been developed for application to cloudy satellite data assimilation. This radiation model was constructed by combining the Optical Path Transmittance (OPTRAN) model, developed for ...

Qing Yue; K. N. Liou; S. C. Ou; B. H. Kahn; P. Yang; G. G. Mace

2007-11-01T23:59:59.000Z

205

A Comparison of Vertical Velocity in Cirrus Obtained from Aircraft and Lidar Divergence Measurements during FIRE  

Science Conference Proceedings (OSTI)

Techniques are presented to obtain vertical velocity in cirrus clouds from in situ aircraft lateral wind measurements and from ground-based remote Doppler lidar measurements. In general, direct measurements of absolute vertical velocity w from ...

I. Gultepe; A. J. Heymsfield; D. H. Lenschow

1990-02-01T23:59:59.000Z

206

Comparison of Methods to Determine Tropical Tropopause Layer Cirrus Formation Mechanisms  

SciTech Connect

A new method of estimating Tropical Tropopause Layer Cirrus (TTLC) formation mechanism (object method) is compared to interpretations of formation from previous studies using back trajectory calculations matched to convection identified from satellites and statistical relationships of TTLC with temperature and water vapor. The object method groups neighboring Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) TTLC cloud profiles into cloud objects and classifies them as convective (35% of TTLC) if they are directly attached to a convective cloud along the CALIPSO track. The percentage of back trajectory calculations that intersect convection (39-95% of TTLC within 5 days) depends strongly on the spatial and temporal resolution of the convection data set, and the manner in which deep convection is identified. Using minimum brightness temperature in 3 hourly, 1{sup o} resolution grid boxes to define convection, 46% of non-convective TTLC (37% of all TTLC) did not trace back to convection within 24 h. Back trajectory calculations of thin cirrus identified by the High Resolution Dynamics Limb Sounder (HIRDLS) gave similar results. Temperature is not a good proxy for formation mechanism as convective and non-convective TTLC frequencies both increase monotonically with decreasing temperature at approximately the same rate. Non-convective TTLC frequencies have a stronger relationship with relative humidity than convective TTLC frequencies, though are not sufficiently different to distinguish object method categories. A decrease in TTL cirrus frequency found at low temperatures in previous studies is caused by insufficient variability in reanalysis temperature data and is not indicative of TTLC formation mechanism.

Riihimaki, Laura D.; McFarlane, Sally A.; Liang, Calvin; Massie, Steven T.; Beagley, Nathaniel; Toth, Travis D.

2012-03-30T23:59:59.000Z

207

Discrimination between thin cirrus and and tropospheric aerosol using  

NLE Websites -- All DOE Office Websites (Extended Search)

Discrimination between thin cirrus and and tropospheric aerosol using Discrimination between thin cirrus and and tropospheric aerosol using multiple measurements from Darwin ARCS Mitchell, Ross CSIRO Category: Aerosols Thin cirrus cloud occurs frequently in the tropics, and is often difficult to distinguish from tropospheric aerosol on the basis of temporal variations in ground based measurements, since both can be rather spatially uniform. In this study we investigate their discrimination by combining data from three instruments at the Darwin Atmospheric Radiation and Cloud Station (ARCS): the Cimel sun photometer (CSP), the micropulse lidar (MPL), and the total sky imager (TSI). The study was carried out over the dry season of 2005, with the usual widespread burning of tropical savanna leading to extensive smoke plumes. It is shown that the locus of data in

208

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

SciTech Connect

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

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

2008-02-27T23:59:59.000Z

209

High and Dry: New Observations of Tropospheric and Cloud Properties above the Greenland Ice Sheet  

Science Conference Proceedings (OSTI)

Cloud and atmospheric properties strongly influence the mass and energy budgets of the Greenland Ice Sheet (GIS). To address critical gaps in the understanding of these systems, a new suite of cloud- and atmosphere-observing instruments has been installed ...

Matthew D. Shupe; David D. Turner; Von P. Walden; Ralf Bennartz; Maria P. Cadeddu; Benjamin B. Castellani; Christopher J. Cox; David R. Hudak; Mark S. Kulie; Nathaniel B. Miller; Ryan R. Neely; III; William D. Neff; Penny M. Rowe

2013-02-01T23:59:59.000Z

210

On the Observed Near Cancellation between Longwave and Shortwave Cloud Forcing in Tropical Regions  

Science Conference Proceedings (OSTI)

Observations based on Earth Radiation Budget Experiment (ERBE) satellite data indicate that there is a near cancellation between tropical longwave and shortwave cloud forcing in regions of deep convective activity. Cloud forcing depends on both ...

J. T. Kiehl

1994-04-01T23:59:59.000Z

211

Calculating Monthly Radiative Fluxes and Heating Rates fromMonthly Cloud Observations  

Science Conference Proceedings (OSTI)

The radiative transfer model from NCAR’s general circulation model CCM3 is modified to calculate monthly radiative fluxes and heating rates from monthly observations of cloud properties from the International Satellite Cloud Climatology Project ...

John W. Bergman; Harry H. Hendon

1998-12-01T23:59:59.000Z

212

Retrieval of Aerosol Optical Depth above Clouds from OMI Observations: Sensitivity Analysis and Case Studies  

Science Conference Proceedings (OSTI)

A large fraction of the atmospheric aerosol load reaching the free troposphere is frequently located above low clouds. Most commonly observed aerosols above clouds are carbonaceous particles generally associated with biomass burning and boreal ...

Omar Torres; Hiren Jethva; P. K. Bhartia

2012-03-01T23:59:59.000Z

213

The Refractive Index Spectra within Clouds from Forward-Scatter Radar Observations  

Science Conference Proceedings (OSTI)

When long-wavelength radars are used to observe the atmosphere, there are occasions when radar return from a volume of cloud is unexpectedly large relative to that predicted by the classical incoherent scatter from individual cloud droplets. The ...

Earl E. Gossard; Richard G. Strauch

1981-02-01T23:59:59.000Z

214

Multiyear Observations of Cloud Lines Associated with the Chesapeake and Delaware Bays  

Science Conference Proceedings (OSTI)

Satellite and corresponding near-surface in situ observations have been made of single- and dual-band cloud events [dubbed anomalous cloud lines (ACLs)] associated with the Chesapeake and Delaware Bays. A previous study developed the basis for ...

Todd D. Sikora; David M. Halverson

2002-08-01T23:59:59.000Z

215

Size Distributions and Dynamical Properties of Shallow Cumulus Clouds from Aircraft Observations and Satellite Data  

Science Conference Proceedings (OSTI)

In this paper aircraft observations of shallow cumulus over Florida during the Small Cumulus Microphysics Study (SCMS) are analyzed. Size distributions of cloud fraction, mass flux, and in-cloud buoyancy flux are derived. These distributions ...

Stefaan M. A. Rodts; Peter G. Duynkerke; Harm J. J. Jonker

2003-08-01T23:59:59.000Z

216

Cluster Analysis of Cloud Properties over the Southern European Mediterranean Area in Observations and a Model  

Science Conference Proceedings (OSTI)

This paper demonstrates how satellite observations of the cloudiness over a complex area such as the European Mediterranean area can be classified into distinct cloud regimes by application of a K-means clustering algorithm to pixel-level cloud ...

Frédérique Chéruy; Filipe Aires

2009-10-01T23:59:59.000Z

217

Observations and Model Simulations of Transport and Precipitation Development in a Seeded Cumulus Congestus Cloud  

Science Conference Proceedings (OSTI)

Observations made by three instrumented aircraft, a Doppler radar, and other data sources were used to follow the initiation and development of precipitation in a small cumulus congestus cloud. The cloud was seeded at its base using an airborne ...

Michael W. Huston; Andrew G. Detwiler; Fred J. Kopp; Jeffrey L. Stith

1991-10-01T23:59:59.000Z

218

Evaluation of MM5 Optically Thin Clouds over Europe in Fall Using ICESat Lidar Spaceborne Observations  

Science Conference Proceedings (OSTI)

The description of clouds in mesoscale models has progressed significantly during recent years by improving microphysical schemes with more physical parameterizations deduced from observations. Recently, the first lidar in space, the Ice, Cloud, ...

H. Chepfer; M. Chiriaco; R. Vautard; J. Spinhirne

2007-07-01T23:59:59.000Z

219

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

SciTech Connect

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

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

2011-08-24T23:59:59.000Z

220

Satellite-Observed Reflectance of Snow and Clouds  

Science Conference Proceedings (OSTI)

The effects of snow and cloud cover on bidirectional reflectance were examined using visible radiation (0.5–0.7 ?m) data measured by NOAA polar orbiting satellites between June 1974 and February 1978. Reflectances resulting from different cloud/...

Alan Robock; Dale Kaiser

1985-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Alteration of Atmospheric Solar Absorption by Clouds: Simulation and Observation  

Science Conference Proceedings (OSTI)

This study investigated theoretically and experimentally two parameters employed in recent attempts to address cloud absorption anomaly. One is the ratio, R, of shortwave cloud radiative forcing (CRF) at the surface to that at the top of the ...

Zhanqing Li; Louis Moreau

1996-05-01T23:59:59.000Z

222

Aircraft Observations of Transport and Diffusion in Cumulus Clouds  

Science Conference Proceedings (OSTI)

A gaseous tracer, sulfur hexafluoride, was used to follow the path of two different AgI cloud seeding aerosols in cumulus clouds. The materials were released at cloud base or midlevels. Plumes sampled at midlevels were found to be relatively ...

Jeffrey L. Stith; Don A. Griffith; R. Lynn Rose; John A. Flueck; James R. Miller Jr.; Paul L. Smith

1986-12-01T23:59:59.000Z

223

A Survey of Changes in Cloud Cover and Cloud Types over Land from Surface Observations, 1971–96  

Science Conference Proceedings (OSTI)

From a dataset of weather observations from land stations worldwide, about 5400 stations were selected as having long periods of record with cloud-type information; they cover all continents and many islands. About 185 million synoptic reports ...

Stephen G. Warren; Ryan M. Eastman; Carole J. Hahn

2007-02-01T23:59:59.000Z

224

A new model of cloud drop distribution that simulates the observed drop  

NLE Websites -- All DOE Office Websites (Extended Search)

A new model of cloud drop distribution that simulates the observed drop A new model of cloud drop distribution that simulates the observed drop clustering: effect of clustering on extinction coefficient estimates Knyazikhin, Yuri Boston University Marshak, Alexander NASA Goddard Space Flight Center Larsen, Michael Michigan Technological University Wiscombe, Warren BNL/NASA Goddard Space Flight Center Category: Modeling Cloud droplet size distribution is one of the most fundamental subjects in cloud physics. Understanding of spatial distribution and small-scale fluctuations of cloud droplets is essential for both cloud physics and atmospheric radiation. For cloud physics, it relates to the coalescence growth of raindrops while for radiation, it has a strong impact on a cloud's radiative properties. We have developed new size dependent models

225

Reconciling Simulated and Observed Views of Clouds: MODIS, ISCCP, and the Limits of Instrument Simulators  

Science Conference Proceedings (OSTI)

The properties of clouds that may be observed by satellite instruments, such as optical thickness and cloud-top pressure, are only loosely related to the way clouds are represented in models of the atmosphere. One way to bridge this gap is through ...

Robert Pincus; Steven Platnick; Steven A. Ackerman; Richard S. Hemler; Robert J. Patrick Hofmann

2012-07-01T23:59:59.000Z

226

Nighttime Multilayered Cloud Detection Using MODIS and ARM Data  

Science Conference Proceedings (OSTI)

This study reports on recent progress toward the discrimination between pixels containing multilayered clouds, specifically optically thin cirrus overlying lower-level water clouds, and those containing single-layered clouds in nighttime Moderate ...

Bryan A. Baum; Richard A. Frey; Gerald G. Mace; Monica K. Harkey; Ping Yang

2003-07-01T23:59:59.000Z

227

Comparison of 30-Day Integrations with and without Cloud-Radiation Interaction  

Science Conference Proceedings (OSTI)

A parameterization package for cloud-radiation interaction is incorporated into a spectral general circulation model (GCM). Fractional cloud amount is predicted quasi-empirically; cloud optical depth is specified for warm clouds and anvil cirrus, ...

C. T. Gordon

1992-07-01T23:59:59.000Z

228

Final Technical Report on Scaling Models of the Internal Variability of Clouds DoE Grant No. DE-FG02-04ER63773  

SciTech Connect

The purpose of this proposal is to gain a better understanding of the space-time correlations of atmospheric fluctuations in clouds through application of methods from statistical physics to high resolution, continuous data sets of cloud observations available at the Department of Energy Atmospheric Radiation Measurement Program archive. In this report we present the accomplishments achieved during the four year period. Starting with the most recent one, we report on two break-throughs in our research that make the fourth year of the project exceptionally successful and markedly outperforming the objectives. The first break-through is on characterization of the structure of cirrus radiative properties at large, intermediate and small, generating cells scales by applying the Fokker-Planck equation method and other methods to ARM millimeter wavelength radar observations collected at the Southern Great Plains site. The second break-through is that we show that different characterizations of the cirrus radiative properties are obtained for different synoptic scale environments. We outline a stochastic approach to investigate the internal structure of radiative properties of cirrus clouds based on empirical modeling and draw conclusions about cirrus dynamical properties in the context of the synoptic environment. Results on the structure of cirrus dynamical properties are consistent with the structure of cirrus based on aircraft in situ measurements, with results from ground-based Raman lidar, and with results from model studies. These achievements would not have been possible without the accomplishments from the previous years on a number of problems that involve application of methods of analysis such as the Fokker-Planck equation approach, Tsallis nonextensive statistical mechanics, detrended fluctuation analysis, and others. These include stochastic analysis of neutrally stratified cirrus layers, internal variability and turbulence in cirrus, dynamical model and nonextensive statistical mechanics of liquid water path fluctuations, etc.

Ivanova, Kristinka

2008-04-24T23:59:59.000Z

229

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

NLE Websites -- All DOE Office Websites (Extended Search)

Manus MJO IOP * Scientific Focus - What are the primary cloud, precipitation, and thermodynamic property differences between the active and suppressed phases of the MJO,...

230

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

SciTech Connect

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

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

2008-02-27T23:59:59.000Z

231

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

SciTech Connect

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

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

2011-06-16T23:59:59.000Z

232

Mammatus Clouds as a Response to Cloud-Base Radiative Heating  

Science Conference Proceedings (OSTI)

Mammatus clouds are the pouchlike lobes seen hanging from mid- to high-level clouds. They can look quite dramatic, but they are also interesting because they provide clues to what controls anvil cirrus dynamic evolution. Thus far, the most ...

Timothy J. Garrett; Clinton T. Schmidt; Stina Kihlgren; Céline Cornet

2010-12-01T23:59:59.000Z

233

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

SciTech Connect

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

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

2009-02-02T23:59:59.000Z

234

The 5–6 December 1991 FIRE IFO II Jet Stream Cirrus Case Study: Possible Influences of Volcanic Aerosols  

Science Conference Proceedings (OSTI)

In presenting an overview of the cirrus clouds comprehensively studied by ground-based and airborne sensors from Coffeyville, Kansas, during the 5–6 December 1992 Project FIRE IFO II case study period, evidence is provided that volcanic aerosols ...

Kenneth Sassen; David O'C. Starr; Gerald G. Mace; Michael R. Poellot; S.H. Melfi; Wynn L. Eberhard; James D. Spinhirne; E.W. Eloranta; Donald E. Hagen; John Hallett

1995-01-01T23:59:59.000Z

235

Validation of Satellite-Based Objective Overshooting Cloud-Top Detection Methods Using CloudSat Cloud Profiling Radar Observations  

Science Conference Proceedings (OSTI)

Two satellite infrared-based overshooting convective cloud-top (OT) detection methods have recently been described in the literature: 1) the 11-?m infrared window channel texture (IRW texture) method, which uses IRW channel brightness temperature (...

Kristopher M. Bedka; Richard Dworak; Jason Brunner; Wayne Feltz

2012-10-01T23:59:59.000Z

236

Observations of Cloud Microstructure at the Centimeter Scale  

Science Conference Proceedings (OSTI)

Current conceptual models of the processes that modify the droplet spectrum in convective clouds starts with entrainment of environmental air followed by turbulent mixing of these parcels into progressively finer filaments. Thus, one would expect,...

Jean-Louis Brenguier

1993-04-01T23:59:59.000Z

237

Comparison of Aircraft Observations with Mixed-Phase Cloud Simulations  

Science Conference Proceedings (OSTI)

In order to provide guidance for the further improvement of a mixed-phase cloud scheme being developed for use in an NWP model, comparisons of dynamical, thermodynamical, and microphysical variables between in situ aircraft data and model data ...

Paul A. Vaillancourt; André Tremblay; Stewart G. Cober; George A. Isaac

2003-04-01T23:59:59.000Z

238

Satellite-Observed Characteristics of Winter Monsoon Cloud Clusters  

Science Conference Proceedings (OSTI)

An objective algorithm is devised which is capable of touting tropical cloud clusters at the point of initiation, tracking them to the paint of dissipation and thereby accumulating statistics on their size distributions and preferred geographical ...

Mark Williams; Robert A. Houze Jr.

1987-02-01T23:59:59.000Z

239

A Comparison of Ground and Satellite Observations of Cloud Cover  

Science Conference Proceedings (OSTI)

A processing scheme that determines cloud height and amount based on radiances from the Visible Infrared Spin Scan Radiometer Atmospheric Sounder (VAS) using a CO2 absorption technique has been installed on the National Environmental Satellite ...

Anthony J. Schreiner; Kathy I. Strabala; David A. Unger; W. Paul Menzel; Gary P. Ellrod; Jackson L. Pellet

1993-10-01T23:59:59.000Z

240

Marine Boundary Layer Cloud Observations in the Azores  

Science Conference Proceedings (OSTI)

The recent deployment of the Atmospheric Radiation Measurement Program (ARM) Mobile Facility at Graciosa Island, Azores, in the context of the Clouds, Aerosol and Precipitation in the Marine Boundary Layer (CAP-MBL) field campaign added the most ...

Jasmine Rémillard; Pavlos Kollias; Edward Luke; Robert Wood

2012-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

What Controls Stratocumulus Radiative Properties? Lagrangian Observations of Cloud Evolution  

Science Conference Proceedings (OSTI)

Marine stratocumulus clouds have a large impact on the earth’s radiation budget. Their optical properties vary on two distinct timescales, one associated with the diurnal cycle of solar insolation and another with the downstream transition to ...

Robert Pincus; Marcia B. Baker; Christopher S. Bretherton

1997-09-01T23:59:59.000Z

242

Cloud Activating Properties of Aerosol Observed during CELTIC  

Science Conference Proceedings (OSTI)

Measurements of aerosol size distribution, chemical composition, and cloud condensation nuclei (CCN) concentration were performed during the Chemical Emission, Loss, Transformation, and Interactions with Canopies (CELTIC) field program at Duke ...

Craig A. Stroud; Athanasios Nenes; Jose L. Jimenez; Peter F. DeCarlo; J. Alex Huffman; Roelof Bruintjes; Eiko Nemitz; Alice E. Delia; Darin W. Toohey; Alex B. Guenther; Sreela Nandi

2007-02-01T23:59:59.000Z

243

Lidar Observations of the Fine-Scale Variability of Marine Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

A Nd:YAG lidar system was flown aboard NASA's ER-2 high altitude aircraft. Observations of cloud top height were made with 70 m along-track and 7.5 m vertical-height resolution. The lidar data observed from an East Pacific stratocumulus cloud ...

Reinout Boers; James D. Spinhirne; William D. Hart

1988-07-01T23:59:59.000Z

244

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

SciTech Connect

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

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

2011-12-24T23:59:59.000Z

245

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

SciTech Connect

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

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

2011-12-24T23:59:59.000Z

246

An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a  

NLE Websites -- All DOE Office Websites (Extended Search)

An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a Decade of Observations at a Mid-Continental Site Min, Qilong State University of New York at Albany Duan, Minzheng State University of New York at Albany Harrison, Lee State University of New York Joseph, Everette Howard University Category: Aerosols Continuing observations of aerosol and cloud optical property have been made using MFRSR and MWR at the ARM SGP site since 1993. Diurnal, monthly, seasonal and interannual variability of aerosol (optical depth and Angstrom coefficient) and cloud (optical depth and effective radius) have been analyzed. We have correlated an "aerosol index" computed from clear-sky observations of MFRSR with cloud droplet mean effective radius to study the

247

Cirrus 1 | Open Energy Information  

Open Energy Info (EERE)

Cirrus 1 Cirrus 1 Jump to: navigation, search Name Cirrus 1 Facility Cirrus 1 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Cirrus Wind Energy Developer Wind Tex Energy Energy Purchaser Merchant Location Tahoka TX Coordinates 33.027294°, -101.696782° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":33.027294,"lon":-101.696782,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

248

Improved Measurements of the Ice Water Content in Cirrus Using a Total-Water Probe  

Science Conference Proceedings (OSTI)

This note describes an improved method for the measurement of the ice water content (IWC) of cirrus cloud using a total water content probe. A previous version of this technique assumed that the air in cloud-containing regions was saturated with ...

Philip R. A. Brown; Peter N. Francis

1995-04-01T23:59:59.000Z

249

Cloud Layer Thicknesses from a Combination of Surface and Upper-Air Observations  

Science Conference Proceedings (OSTI)

Cloud layer thicknesses are derived from base and top altitudes by combining 14 years (1975–1988) of surface and upper-air observations at 63 sites in the Northern Hemisphere. Rawinsonde observations are employed to determine the locations of ...

Kirk D. Poore; Junhong Wang; William B. Rossow

1995-03-01T23:59:59.000Z

250

Simulated Doppler Radar Observations of Inhomogeneous Clouds: Application to the EarthCARE Space Mission  

Science Conference Proceedings (OSTI)

A new simulation technique for spaceborne Doppler radar observations that was developed specifically for inhomogeneous targets is presented. Cloud inhomogeneity affects Doppler observations in two ways. First, line-of-sight velocities within the ...

N. A. J. Schutgens

2008-01-01T23:59:59.000Z

251

Two-moment Bulk Stratiform Cloud Microphysics in the Grid-point Atmospheric Model of IAP LASG (GAMIL)  

SciTech Connect

A two-moment bulk stratiform microphysics scheme, including recently developed physically-based droplet activation/ice nucleation parameterizations has been implemented into the Grid-point Atmospheric Model of IAP LASG (GAMIL) as an effort to enhance the model capability for studying aerosol indirect effects. Unlike the previous one-moment cloud microphysics scheme, the new scheme produces reasonable representation of cloud particle size and number concentration. This scheme captures the observed spatial variations in cloud droplet number concentrations. Simulated ice crystal number concentrations in cirrus clouds qualitatively agree with in-situ observations. The longwave and shortwave cloud forcing are in better agreement with observations. Sensitivity tests show that the column cloud droplet number concentrations calculated from two different droplet activation parameterizations are similar. However, ice crystal number concentration in mixed-phased clouds is sensitive to different heterogeneous freezing formulations. The simulation with high ice crystal number concentration in mixed-phase clouds has less liquid water path and weaker cloud forcing. Furthermore, ice crystal number concentration in cirrus clouds is sensitive to different ice nucleation parameterizations. Sensitivity tests also suggest that impact of pre-existing ice crystals on homogeneous freezing in old clouds should be taken into account.

Shi, Xiangjun; Wang, Bin; Liu, Xiaohong; Wang, Minghuai

2013-05-01T23:59:59.000Z

252

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

SciTech Connect

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

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

2005-03-18T23:59:59.000Z

253

Crystal-Face Science Posters - Post-mission Science Posters from the Cirrus Regional Study of Tropical Anvils and Cirrus Layers  

DOE Data Explorer (OSTI)

The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) took place in the summer of 2002 over Key West, Florida. It was a measurement campaign that investigated the physical properties and formation processes of tropical cirrus clouds. Six aircraft with various instruments flew missions, gathering data that were compared with ground-based instrument data and that would be used in the modeling of the Earth's climate. DOE was only one of several federal agencies involved, along with various universities and science institutes. The Crystal-Face numeric data sets are available in DOE's ARM Archive at http://www.archive.arm.gov/armlogin/login.jsp and in NASA's ARCS archive at http://espoarchive.nasa.gov/archive/arcs/crystalf/images/npol_1/. Various sets of data are also available at some of the participating universities. The official home page for Crystal-Face is http://www.espo.nasa.gov/crystalface/index.html.

254

Evaluating the Cloud Cover Forecast of NCEP Global Forecast System with Satellite Observation  

E-Print Network (OSTI)

To assess the quality of daily cloud cover forecast generated by the operational global numeric model, the NCEP Global Forecast System (GFS), we compose a large sample with outputs from GFS model and satellite observations from the International Satellite Cloud Climatology Project (ISCCP) in the period of July 2004 to June 2008, to conduct a quantitative and systematic assessment of the performance of a cloud model that covers a relatively long range of time, basic cloud types, and in a global view. The evaluation has revealed the goodness of the model forecast, which further illustrates our completeness on understanding cloud generation mechanism. To quantity the result, we found a remarkably high correlation between the model forecasts and the satellite observations over the entire globe, with mean forecast error less than 15% in most areas. Considering a forecast within 30% difference to the observation to be a "good" one, we find that the probability for the GFS model to make good forecasts varies between...

Ye, Quanzhi

2011-01-01T23:59:59.000Z

255

Crystal-Face Archive of Images: Images from the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment  

DOE Data Explorer (OSTI)

The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) took place in the summer of 2002 over Key West, Florida. It was a measurement campaign that investigated the physical properties and formation processes of tropical cirrus clouds. Six aircraft with various instruments flew missions, gathering data that were compared with ground-based instrument data and that would be used in the modeling of the EarthĆs climate. DOE was only one of several federal agencies involved, along with various universities and science institutes. The Crystal-Face numeric data sets are available in DOEĆs ARM Archive at http://www.archive.arm.gov/armlogin/login.jsp and in NASAĆs ARCS archive at http://espoarchive.nasa.gov/archive/arcs/crystalf/images/npol_1/. Various sets of data are also available at some of the participating universities. The official home page for Crystal-Face is http://www.espo.nasa.gov/crystalface/index.html. See the 52 science posters at http://www.espo.nasa.gov/crystalface/posters.html

256

Skylab Near-Infrared Observations of Clouds Indicating Supercooled Liquid Water Droplets  

Science Conference Proceedings (OSTI)

Orographically-induced lee-wave clouds were observed over New Mexico by a multichannel scanning radiometer on Skylab during December 1973. Channels centered at 0.83, 1.61 and 2.125 ?m were used to determine the cloud optical thickness, ...

Robert J. Curran; Man-Li C. Wu

1982-03-01T23:59:59.000Z

257

Comparison of Monte Carlo Calculations with Observations of Light Scattering in Finite Clouds  

Science Conference Proceedings (OSTI)

Two experimental data sets have been compared with calculations of solar radiation scattered by finite cumulus clouds. The first approach was to observe the radiation exiting the sides of cumulus clouds from 0.8 to 3.0 km in vertical thickness as ...

Thomas B. McKee; Mark DeMaria; James A. Kuenning; Stephen K. Cox

1983-04-01T23:59:59.000Z

258

Evaluation of Cloud-Resolving Model Intercomparison Simulations Using TWP-ICE Observations: Precipitation and Cloud Structure  

SciTech Connect

The Tropical Warm Pool – International Cloud Experiment (TWP-ICE) provided high quality model forcing and observational datasets through which detailed model and observational intercomparisons could be performed. In this first of a two part study, precipitation and cloud structures within nine cloud-resolving model simulations are compared with scanning radar reflectivity and satellite infrared brightness temperature observations during an active monsoon period from 19 to 25 January 2006. Most simulations slightly overestimate volumetric convective rainfall. Overestimation of simulated convective area by 50% or more in several simulations is somewhat offset by underestimation of mean convective rain rates. Stratiform volumetric rainfall is underestimated by 13% to 53% despite overestimation of stratiform area by up to 65% because stratiform rain rates in every simulation are much lower than observed. Although simulations match the peaked convective radar reflectivity distribution at low levels, they do not reproduce the peaked distributions observed above the melting level. Simulated radar reflectivity aloft in convective regions is too high in most simulations. In stratiform regions, there is a large spread in model results with none resembling observed distributions. Above the melting level, observed radar reflectivity decreases more gradually with height than simulated radar reflectivity. A few simulations produce unrealistically uniform and cold 10.8-?m infrared brightness temperatures, but several simulations produce distributions close to observed. Assumed ice particle size distributions appear to play a larger role than ice water contents in producing incorrect simulated radar reflectivity distributions aloft despite substantial differences in mean graupel and snow water contents across models.

Varble, Adam; Fridlind, Ann; Zipser, Edward J.; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; McFarlane, Sally A.; Pinty, Jean-Pierre; Shipway, Ben

2011-10-04T23:59:59.000Z

259

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

E-Print Network (OSTI)

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

Shupe, Matthew

260

Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties  

E-Print Network (OSTI)

ice nucleation in ice and mixed- phase clouds are: 1. WhatWhat is the phase, hygroscopicity, and warm and ice cloudmixed phase clouds, while cirrus clouds are composed of ice

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

The 27–28 October 1986 FIRE Cirrus Case Study: Retrieval of Cloud Particle Sizes and Optical Depths from Comparative Analyses of Aircraft and Satellite-based Infrared Measurements  

Science Conference Proceedings (OSTI)

Infrared radiance measurements were acquired from a narrow-field nadir-viewing radiometer based on the NASA ER-2 aircraft during a coincident Landsat 5 overpass on 28 October 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. ...

Philip D. Hammer; Francisco P. J. Valero; Stefan Kinne

1991-07-01T23:59:59.000Z

262

Cloud and Radiative Characteristics of Tropical Deep Convective Systems in Extended Cloud Objects from CERES Observations  

Science Conference Proceedings (OSTI)

The physical and radiative properties of tropical deep convective systems for the period from January to August 1998 are examined with the use of Clouds and the Earth’s Radiant Energy System Single-Scanner Footprint (SSF) data from the Tropical ...

Zachary A. Eitzen; Kuan-Man Xu; Takmeng Wong

2009-11-01T23:59:59.000Z

263

WHAM Observations of H-alpha from High-Velocity Clouds Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H-alpha line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H-alpha emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

Tufte, S L; Madsen, G J; Haffner, L M; Reynolds, R J

2002-01-01T23:59:59.000Z

264

WHAM Observations of H-alpha from High-Velocity Clouds: Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H-alpha line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H-alpha emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

S. L. Tufte; J. D. Wilson; G. J. Madsen; L. M. Haffner; R. J. Reynolds

2002-06-12T23:59:59.000Z

265

A Comparison of Simulated Cloud Radar Output from the Multiscale Modeling Framework Global Climate Model with CloudSat Cloud Radar Observations  

Science Conference Proceedings (OSTI)

Over the last few years a new type of global climate model (GCM) has emerged in which a cloud-resolving model is embedded into each grid cell of a GCM. This new approach is frequently called a multiscale modeling framework (MMF) or superparameterization. In this article we present a comparison of MMF output with radar observations from the NASA CloudSat mission, which uses a near-nadir-pointing millimeter-wavelength radar to probe the vertical structure of clouds and precipitation. We account for radar detection limits by simulating the 94 GHz radar reflectivity that CloudSat would observe from the high-resolution cloud-resolving model output produced by the MMF. Overall, the MMF does a good job of reproducing the broad pattern of tropical convergence zones, subtropical belts, and midlatitude storm tracks, as well as their changes in position with the annual solar cycle. Nonetheless, the comparison also reveals a number of model shortfalls including (1) excessive hydrometeor coverage at all altitudes over many convectively active regions, (2) a lack of low-level hydrometeors over all subtropical oceanic basins, (3) excessive low-level hydrometeor coverage (principally precipitating hydrometeors) in the midlatitude storm tracks of both hemispheres during the summer season (in each hemisphere), and (4) a thin band of low-level hydrometeors in the Southern Hemisphere of the central (and at times eastern and western) Pacific in the MMF, which is not observed by CloudSat. This band resembles a second much weaker ITCZ but is restricted to low levels.

Marchand, Roger T.; Haynes, J. M.; Mace, Gerald G.; Ackerman, Thomas P.; Stephens, Graeme L.

2009-01-13T23:59:59.000Z

266

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

SciTech Connect

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

Turner, David D.

2003-06-01T23:59:59.000Z

267

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

Science Conference Proceedings (OSTI)

Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil ...

Scott W. Powell; Robert A. Houze Jr.; Anil Kumar; Sally A. McFarlane

2012-09-01T23:59:59.000Z

268

Retrieval of Cloud Microphysical Properties from Thermal Infrared Observations by a Fast Iterative Radiance Fitting Method  

Science Conference Proceedings (OSTI)

An algorithm is presented for inferring the IR optical depth, effective radius, and liquid water path of clouds from multispectral observations of emitted thermal radiation, which takes advantage of the larger number of spectral channels of ...

C. Rathke; J. Fischer

2000-11-01T23:59:59.000Z

269

Model Rain and Clouds over Oceans: Comparison with SSM/I Observations  

Science Conference Proceedings (OSTI)

A comparison of global model cloud and rain parameterization output with satellite observed radiances was carried out. Hydrometeor profiles from ECMWF operational short-range forecasts were combined with a microwave radiative transfer model to ...

Frédéric Chevallier; Peter Bauer

2003-07-01T23:59:59.000Z

270

Observations of Record Cold Cloud-Top Temperatures in Tropical Cyclone Hilda (1990)  

Science Conference Proceedings (OSTI)

A detailed analysis is made of the development of a region of cold cloud-top temperatures in Tropical Cyclone Hilda (1990) in the Coral Sea off eastern Australia. Observed temperatures of approximately 173 K (?100°C) from two independent ...

Elizabeth E. Ebert; Greg J. Holland

1992-10-01T23:59:59.000Z

271

Cloud-to-Ground Lightning Observations from TOGA COARE: Selected Results and Lightning Location Algorithms  

Science Conference Proceedings (OSTI)

Recently, observations of electrified oceanic convection and associated cloud-to-ground (CG) lightning were obtained over the tropical western Pacific Ocean during TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response ...

Walter A. Petersen; Steven A. Rutledge; Richard E. Orville

1996-04-01T23:59:59.000Z

272

A Clustering Approach to Compare Cloud Model Simulations to Satellite Observations  

Science Conference Proceedings (OSTI)

Cloud-resolving models (CRMs) offer an important pathway to interpret satellite observations of microphysical properties of storms. High-frequency microwave brightness temperatures (Tbs) respond to precipitating-sized ice particles and can ...

Fang Wang; Christian Kummerow

2012-11-01T23:59:59.000Z

273

The Turbulence Structure in a Continental Stratocumulus Cloud from Millimeter-Wavelength Radar Observations  

Science Conference Proceedings (OSTI)

The turbulent-scale vertical velocity structure in a continental stratocumulus cloud is studied using a 3-mm wavelength Doppler radar operating in a vertically pointing mode. The radar observations provided 30-m sampling in the vertical with 2-s ...

Pavlos Kollias; Bruce Albrecht

2000-08-01T23:59:59.000Z

274

Ground-Based and Satellite Observations of Cloud Fields in the Netherlands  

Science Conference Proceedings (OSTI)

A study is performed on the combination of ground-based and satellite observations for the derivation of cloud properties. Ground-based measurements from a lidar ceilometer and an infrared radiometer were combined with measurements of the NOAA ...

Arnout Feut; André van Lammeren

1996-09-01T23:59:59.000Z

275

Photographic Documentation of Some Distinctive Cloud Forms Observed Beneath a Large Cumulonimbus  

Science Conference Proceedings (OSTI)

Photographs of some variform cloud features observed in the inflow sector of an intense thunderstorm that occurred in southeastern Montana on 11 July 1981 are described. Associated meteorological conditions are interpreted within the context of ...

J. C. Fankhauser; G. M. Barnes; L. J. Miller; P. M. Roskowski

1983-05-01T23:59:59.000Z

276

Melting Layer Cloud Observed during R/V Mirai Cruise MR01-K05  

Science Conference Proceedings (OSTI)

In this study, cloud profiling radar and lidar were used to determine the frequency distribution of the base heights of cloudy layers with little (or no) falling condensate particles. The data were obtained from stationary observations conducted ...

Kazuaki Yasunaga; Kunio Yoneyama; Hisayuki Kubota; Hajime Okamoto; Atsushi Shimizu; Hiroshi Kumagai; Masaki Katsumata; Nobuo Sugimoto; Ichiro Matsui

2006-11-01T23:59:59.000Z

277

Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models  

Science Conference Proceedings (OSTI)

We use observations of robust scaling behavior in clouds and precipitation to derive constraints on how partitioning of precipitation should change with model resolution. Our analysis indicates that 90–99% of stratiform precipitation should occur ...

Travis A. O’Brien; Fuyu Li; William D. Collins; Sara A. Rauscher; Todd D. Ringler; Mark Taylor; Samson M. Hagos; L. Ruby Leung

278

RACORO Extended-Term Aircraft Observations of Boundary-Layer Clouds  

SciTech Connect

A first-of-a-kind, extended-term cloud aircraft campaign was conducted to obtain an in-situ statistical characterization of boundary-layer clouds needed to investigate cloud processes and refine retrieval algorithms. Coordinated by the Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF), the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign operated over the ARM Southern Great Plains (SGP) site from 22 January to 30 June 2009, collecting 260 h of data during 59 research flights. A comprehensive payload aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft measured cloud microphysics, solar and thermal radiation, aerosol properties, and atmospheric state parameters. Proximity to the SGP's extensive complement of surface measurements provides ancillary data that supports modeling studies and enables evaluating a variety of surface retrieval algorithms. The five-month duration enabled sampling a range of conditions associated with the seasonal transition from winter to summer. Although about two-thirds of the cloud flights occurred in May and June, boundary-layer cloud fields were sampled under a variety of environmental and aerosol conditions, with about 75% of the flights occurring in cumulus and stratocumulus. Preliminary analyses show how these data are being used to analyze cloud-aerosol relationships, determine the aerosol sizes that are responsible for nucleating cloud drops, characterize the horizontal variability of the cloud radiative impacts, and evaluate air-borne and surface-based cloud property retrievals. We discuss how conducting an extended-term campaign requires a simplified operating paradigm that is different from that used for typical, short-term, intensive aircraft field programs.

Vogelmann, A. M.; McFarquhar, Greg; Ogren, John A.; Turner, David D.; Comstock, Jennifer M.; Feingold, G.; Long, Charles N.; Jonsson, Haf; Bucholtz, Anthony; Collins, Donald R.; Diskin, G. S.; Gerber, H.; Lawson, Paul; Woods, Roy; Andrews, Elizabeth; Yang, Hee-Jung; Chiu, Christine J.; Hartsock, Daniel; Hubbe, John M.; Lo, Chaomei; Marshak, A.; Monroe, Justin; McFarlane, Sally A.; Schmid, Beat; Tomlinson, Jason M.; Toto, Tami

2012-06-30T23:59:59.000Z

279

Constraining cloud lifetime effects of aerosols using A-Train satellite observations  

Science Conference Proceedings (OSTI)

Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change. Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences. Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (S{sub pop}), is a good measure of the liquid water path response to aerosol perturbation ({lambda}), as both Spop and {lambda} strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets. This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models. S{sub pop} in marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations. This implies a substantially smaller impact on shortwave cloud radiative forcing (SWCF) over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models). Further work is needed to quantify the uncertainties in satellite-derived estimates of S{sub pop} and to examine S{sub pop} in high-resolution models.

Wang, Minghuai; Ghan, Steven J.; Liu, Xiaohong; Ecuyer, Tristan L.; Zhang, Kai; Morrison, H.; Ovchinnikov, Mikhail; Easter, Richard C.; Marchand, Roger; Chand, Duli; Qian, Yun; Penner, Joyce E.

2012-08-15T23:59:59.000Z

280

Evaluation of Cloud-Resolving Model Intercomparison Simulations Using TWP-ICE Observations: Precipitation and Cloud Structure  

SciTech Connect

The Tropical Warm Pool - International Cloud Experiment (TWP-ICE) provided high quality model forcing and observational datasets through which detailed model and observational intercomparisons could be performed. In this first of a two part study, precipitation and cloud structures within nine cloud-resolving model simulations are compared with scanning radar reflectivity and satellite infrared brightness temperature observations during an active monsoon period from 19 to 25 January 2006. Most simulations slightly overestimate volumetric convective rainfall. Overestimation of simulated convective area by 50% or more in several simulations is somewhat offset by underestimation of mean convective rain rates. Stratiform volumetric rainfall is underestimated by 13% to 53% despite overestimation of stratiform area by up to 65% because stratiform rain rates in every simulation are much lower than observed. Although simulations match the peaked convective radar reflectivity distribution at low levels, they do not reproduce the peaked distributions observed above the melting level. Simulated radar reflectivity aloft in convective regions is too high in most simulations. 29 In stratiform regions, there is a large spread in model results with none resembling 30 observed distributions. Above the melting level, observed radar reflectivity decreases 31 more gradually with height than simulated radar reflectivity. A few simulations produce 32 unrealistically uniform and cold 10.8-?m infrared brightness temperatures, but several 33 simulations produce distributions close to observed. Assumed ice particle size 34 distributions appear to play a larger role than ice water contents in producing incorrect 35 simulated radar reflectivity distributions aloft despite substantial differences in mean 36 graupel and snow water contents across models. 37

Varble, Adam C.; Fridlind, Ann; Zipser, Ed; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; McFarlane, Sally A.; Pinty, Jean-Pierre; Shipway, Ben

2011-06-24T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Clouds as Seen by Satellite Sounders (3I) and Imagers (ISCCP). Part III: Spatial Heterogeneity and Radiative Effects  

Science Conference Proceedings (OSTI)

Their relatively good spectral resolution makes infrared sounders very useful for the determination of cloud properties (day and night), and their coarse spatial resolution has less effect on clouds with large spatial extents like cirrus clouds. ...

C. J. Stubenrauch; W. B. Rossow; N. A. Scott; A. Chédin

1999-12-01T23:59:59.000Z

282

Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

heated by the sun, produces rising columns of air in which the moisture condenses into tall fleecy white clouds At night, when the sky is clear, the earth cools to give those...

283

Factors influencing the microphysics and radiative properties of liquid-dominated Arctic clouds: insight from observations of aerosol and clouds during ISDAC  

SciTech Connect

Aircraft measurements during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in April 2008 are used to investigate aerosol indirect effects in Arctic clouds. Two aerosol-cloud regimes are considered in this analysis: single-layer stratocumulus cloud with below-cloud aerosol concentrations (N{sub a}) below 300 cm{sup -3} on April 8 and April 26-27 (clean cases); and inhomogeneous layered cloud with N{sub a} > 500 cm{sup -3} below cloud base on April 19-20, concurrent with a biomass burning episode (polluted cases). Vertical profiles through cloud in each regime are used to determine average cloud microphysical and optical properties. Positive correlations between the cloud droplet effective radius (Re) and cloud optical depth ({tau}) are observed for both clean and polluted cases, which are characteristic of optically-thin, non-precipitating clouds. Average Re values for each case are {approx} 6.2 {mu}m, despite significantly higher droplet number concentrations (Nd) in the polluted cases. The apparent independence of Re and Nd simplifies the description of indirect effects, such that {tau} and the cloud albedo (A) can be described by relatively simple functions of the cloud liquid water path. Adiabatic cloud parcel model simulations show that the marked differences in Na between the regimes account largely for differences in droplet activation, but that the properties of precursor aerosol also play a role, particularly for polluted cases where competition for vapour amongst the more numerous particles limits activation to larger and/or more hygroscopic particles. The similarity of Re for clean and polluted cases is attributed to compensating droplet growth processes for different initial droplet size distributions.

Earle, Michael; Liu, Peter S.; Strapp, J. Walter; Zelenyuk, Alla; Imre, D.; McFarquhar, Greg; Shantz, Nicole C.; Leaitch, W. R.

2011-11-04T23:59:59.000Z

284

ARM - Publications: Science Team Meeting Documents: Nighttime cirrus  

NLE Websites -- All DOE Office Websites (Extended Search)

Nighttime cirrus detection using AIRS radiances and total column Nighttime cirrus detection using AIRS radiances and total column precipitable water Kahn, Brian Jet Propulsion Laboratory Liou, Kuo-Nan UCLA A method of cirrus detection at nighttime is presented that utilizes 3.8 and 10.4 m infrared (IR) window brightness temperature differences (dBT) and total column precipitable water (PW) measurements. This technique is applied to the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit A (AMSU-A) instrument suite onboard EOS-Aqua, where dBT is determined from sets of carefully selected AIRS window channels, while PW is derived from the synergistic AIRS and AMSU-A water vapor retrievals. Simulated and observed dBT for a particular value of PW is not constant; several physical factors impact dBT, including the variability in

285

Study of Ice Cloud Properties from Synergetic Use of Satellite Observations and Modeling Capabilities  

E-Print Network (OSTI)

The dissertation first investigates the single-scattering properties of inhomogeneous ice crystals containing air bubbles. Specifically, a combination of the ray-tracing technique and the Monte Carlo method is used to simulate the scattering of light by randomly oriented large hexagonal ice crystals containing spherical or spheroidal air bubbles. The effect of the air bubbles within ice crystals is to smooth the phase functions, diminish the 22° and 46° halo peaks, and reduce the backscatter in comparison with the case of bubble-free ice crystals. Cloud reflectance look-up tables were generated at the wavelengths of 0.65 ?m and 2.13 ?m to examine the impact of accounting for air bubbles in ice crystal morphology on the retrieval of ice cloud optical thickness and effective particle size. To investigate the effect of the representation of aggregates on electromagnetic scattering calculations, an algorithm is developed to efficiently specify the geometries of aggregates and to compute some of their geometric parameters such as the projected area. Based on in situ observations, aggregates are defined as clusters of hexagonal plates with a chain-like overall shape. An aggregate model is developed with 10 ensemble members, each consisting of between 4-12 hexagonal plates. The scattering properties of an individual aggregate ice particle are computed using the discrete dipole approximation or an Improved Geometric Optics Method, depending upon the size parameter. The aggregate model provides an accurate and computationally efficient way to represent all aggregates occurring within ice clouds. We developed an algorithm to determine an appropriate ice cloud model for application to satellite-based retrieval of ice cloud properties. Collocated Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging SpectroRadiometer (MISR) data are used to retrieve the optical thicknesses of ice clouds as a function of scattering angle in the nine MISR viewing directions. The difference between cloud optical thickness and its averaged value over the nine viewing angles can be used to validate the ice cloud models. Using the data obtained on 2 July 2009, an appropriate ice cloud model is determined. With the presence of all the uncertainties in the current operational satellite-based retrievals of ice cloud properties, this ice cloud model has excellent performance in terms of consistency in cloud property retrievals with the nine MISR viewing angles.

Xie, Yu

2010-12-01T23:59:59.000Z

286

FINAL REPORT FOR THE DOE/ARM PROJECT TITLED Representation of the Microphysical and Radiative Properties of Ice Clouds in SCMs and GCMs  

SciTech Connect

The broad goal of this research is to improve climate prediction through better representation of cirrus cloud microphysical and radiative properties in global climate models (GCMs). Clouds still represent the greatest source of uncertainty in climate prediction, and the representation of ice clouds is considerably more challenging than liquid water clouds. While about 40% of cloud condensate may be in the form of ice by some estimates, there have been no credible means of representing the ice particle size distribution and mass removal rates from ice clouds in GCMs. Both factors introduce large uncertainties regarding the global net flux, the latter factor alone producing a change of 10 W/m2 in the global net flux due to plausible changes in effective ice particle fallspeed. In addition, the radiative properties of ice crystals themselves are in question. This research provides GCMs with a credible means of representing the full (bimodal) ice particle size distribution (PSD) in ice clouds, including estimates of the small crystal (D < 65 microns) mode of the PSD. It also provides realistic estimates of mass sedimentation rates from ice clouds, which have a strong impact on their ice contents and radiative properties. This can be done through proper analysis of ice cloud microphysical data from ARM and other field campaigns. In addition, this research tests the ice cloud radiation treatment developed under two previous ARM projects by comparing it against laboratory measurements of ice cloud extinction efficiency and by comparing it with explicit theoretical calculations of ice crystal optical properties. The outcome of this project includes two PSD schemes for ice clouds; one appropriate for mid-latitude cirrus clouds and another for tropical anvil cirrus. Cloud temperature and ice water content (IWC) are the inputs for these PSD schemes, which are based on numerous PSD observations. The temperature dependence of the small crystal mode of the PSD for tropical anvils is opposite to that of mid-latitude cirrus, and this results in very different radiative properties for these two types of cirrus at temperatures less than about 50 C for a given ice water path. In addition, the representative PSD fall velocity is strongly influenced by the small crystal mode, and for temperatures less than 52 C, this fall velocity for mid-latitude cirrus is 2-8 times greater than for tropical anvil cirrus. Finally, the treatment of ice cloud optical properties was found to agree with laboratory measurements and exact theory within 15% for any given wavelength, PSD and ice particle shape. This treatment is analytical, formulated in terms of the PSD and ice particle shape properties. It thus provides the means for explicitly coupling the ice cloud microphysical and radiative properties, and can treat any combination of ice particle shape. It is very inexpensive regarding computer time. When these three deliverables were incorporated into the GCM at the National Center for Atmospheric Research (NCAR) under another project, it was found that the sunlight reflected and the amount of upwelling heat absorbed by cirrus clouds depended strongly on the PSD scheme used (i.e. mid-latitude or tropical anvil). This was largely due to the fall velocities associated with the two PSD schemes, although the PSD shape was also important.

Mitchell, David L.

2005-08-08T23:59:59.000Z

287

Cloud Model-Based Simulation of Spaceborne Radar Observations  

Science Conference Proceedings (OSTI)

Simulations of observations from potential spaceborne radars are made based on storm structure generated from the three-dimensional (3D) Goddard cumulus ensemble model simulation of an intense overland convective system. Five frequencies of 3, 10,...

H-Y. M. Yeh; N. Prasad; R. Meneghini; W-K. Tao; J. A. Jones; R. F. Adler

1995-01-01T23:59:59.000Z

288

Measurements of the Ice Water Content in Cirrus Using an Evaporative Technique  

Science Conference Proceedings (OSTI)

A technique for the measurement of the ice water content (IWC) of cirrus clouds is described. The IWC is obtained by the measurement of the total water content (TWC) and the subtraction of the saturation specific humidity with respect to ice at ...

Philip R. A. Brown

1993-08-01T23:59:59.000Z

289

Measuring Crystal Size in Cirrus Using 35- and 94-GHz Radars  

Science Conference Proceedings (OSTI)

Results are presented from a case study in which coincident 35- and 94-GHz radars located at Chilbolton, England, were used to measure crystal size in cirrus clouds. In the presence of larger crystals the 94-GHz radar scatters sufficiently beyond ...

Robin J. Hogan; Anthony J. Illingworth; Henri Sauvageot

2000-01-01T23:59:59.000Z

290

Validation of IIR/CALIPSO Level 1 Measurements by Comparison with Collocated Airborne Observations during CIRCLE-2 and Biscay ‘08 Campaigns  

Science Conference Proceedings (OSTI)

In the frame of validation of the spatial observations from the radiometer IIR on board CALIPSO, the two airborne campaigns Cirrus Cloud Experiment (CIRCLE)-2 and Biscay ‘08 took place in 2007 and 2008 in the western part of France, over the ...

Odran Sourdeval; Gérard Brogniez; Jacques Pelon; Laurent C.-Labonnote; Philippe Dubuisson; Frédéric Parol; Damien Josset; Anne Garnier; Michaël Faivre; Andreas Minikin

2012-05-01T23:59:59.000Z

291

Use of In Situ Observations to Characterize Cloud Microphysical and Radiative Properties: Application to Climate Studies  

NLE Websites -- All DOE Office Websites (Extended Search)

Use of In Situ Observations to Characterize Use of In Situ Observations to Characterize Cloud Microphysical and Radiative Properties: Application to Climate Studies G. M. McFarquhar and T. Nousiainen Department of Atmospheric Sciences University of Illinois Urbana, Illinois M. S. Timlin, S. F. Iacobellis, and R. C. J. Somerville Scripps Institution of Oceanography La Jolla, California Introduction Cloud radiative feedback is the most important effect determining climate response to human activity. Ice clouds reflect solar radiation and absorb thermal emission from the ground and the lower atmosphere and emit infrared radiation to space. The representation of these processes in models affects future climate predictions and there is much uncertainty in the representation of these processes. The size and

292

The Diurnal Cycle of Cloud-Top Height and Cloud Cover over the Southeastern Pacific as Observed by GOES-10  

Science Conference Proceedings (OSTI)

The diurnal cycles in cloud-top height Htop and cloud fraction (CF) in the southeastern Pacific stratocumulus region were determined for October–November 2008 by analyzing data from Geostationary Operational Environmental Satellite-10 (GOES-10) ...

David Painemal; Patrick Minnis; Larry O'Neill

2013-08-01T23:59:59.000Z

293

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

Science Conference Proceedings (OSTI)

A new automated daytime cumulonimbus/towering cumulus (Cb/TCu) cloud detection method for the months of May–September is presented that combines information on cloud physical properties retrieved from the Spinning Enhanced Visible and Infrared ...

Cintia Carbajal Henken; Maurice J. Schmeits; Hartwig Deneke; Rob A. Roebeling

2011-07-01T23:59:59.000Z

294

Cloud Droplet Residual Particle Microphysics in Marine Stratocumulus Clouds Observed during the Monterey Area Ship Track Experiment  

Science Conference Proceedings (OSTI)

The effect of marine boundary layer pollution level (as determined by the aerosol particle number concentration) on the size distribution of aerosol particles that formed cloud droplets in marine stratiform clouds is examined. In situ ...

Elisabeth Öström; Kevin J. Noone; Robert A. Pockalny

2000-08-01T23:59:59.000Z

295

Comparison between Observed Convective Cloud-Base Heights and Lifting Condensation Level for Two Different Lifted Parcels  

Science Conference Proceedings (OSTI)

Approximately 400 Automated Surface Observing System (ASOS) observations of convective cloud-base heights at 2300 UTC were collected from April through August of 2001. These observations were compared with lifting condensation level (LCL) heights ...

Jeffrey P. Craven; Ryan E. Jewell; Harold E. Brooks

2002-08-01T23:59:59.000Z

296

Climatology of High Cloud Dynamics Using Profiling ARM Doppler Radar Observations  

Science Conference Proceedings (OSTI)

Ice cloud properties are influenced by cloud-scale vertical air motion. Dynamical properties of ice clouds can be determined via Doppler measurements from ground-based, profiling cloud radars. Here, the decomposition of the Doppler velocities into ...

Heike Kalesse; Pavlos Kollias

297

VLT-FLAMES observations of young stellar clusters in the Magellanic Clouds  

E-Print Network (OSTI)

We introduce our VLT-FLAMES survey of massive stars in the Galaxy and the Magellanic Clouds, giving details of the observations in our younger fields in the LMC and SMC. In particular we highlight a new O2.5-type star discovered in N11, and Be-type stars in NGC 346 with permitted Fe II emission lines in their spectra. We give an overview of the distribution of spectral types in these fields and summarize the observed binary fraction.

C. J. Evans; D. J. Lennon; S. J. Smartt

2005-08-30T23:59:59.000Z

298

MAGNETIZATION OF CLOUD CORES AND ENVELOPES AND OTHER OBSERVATIONAL CONSEQUENCES OF RECONNECTION DIFFUSION  

SciTech Connect

Recent observational results for magnetic fields in molecular clouds reviewed by Crutcher seem to be inconsistent with the predictions of the ambipolar diffusion theory of star formation. These include the measured decrease in mass to flux ratio between envelopes and cores, the failure to detect any self-gravitating magnetically subcritical clouds, the determination of the flat probability distribution function (PDF) of the total magnetic field strengths implying that there are many clouds with very weak magnetic fields, and the observed scaling B{proportional_to}{rho}{sup 2/3} that implies gravitational contraction with weak magnetic fields. We consider the problem of magnetic field evolution in turbulent molecular clouds and discuss the process of magnetic field diffusion mediated by magnetic reconnection. For this process that we termed 'reconnection diffusion', we provide a simple physical model and explain that this process is inevitable in view of the present-day understanding of MHD turbulence. We address the issue of the expected magnetization of cores and envelopes in the process of star formation and show that reconnection diffusion provides an efficient removal of magnetic flux that depends only on the properties of MHD turbulence in the core and the envelope. We show that as the amplitude of turbulence as well as the scale of turbulent motions decrease from the envelope to the core of the cloud, the diffusion of the magnetic field is faster in the envelope. As a result, the magnetic flux trapped during the collapse in the envelope is being released faster than the flux trapped in the core, resulting in much weaker fields in envelopes than in cores, as observed. We provide simple semi-analytical model calculations which support this conclusion and qualitatively agree with the observational results. Magnetic reconnection is also consistent with the lack of subcritical self-gravitating clouds, with the observed flat PDF of field strengths, and with the scaling of field strength with density. In addition, we demonstrate that the reconnection diffusion process can account for the empirical Larson relations and list a few other implications of the reconnection diffusion concept. We argue that magnetic reconnection provides a solution to the magnetic flux problem of star formation that agrees better with observations than the long-standing ambipolar diffusion paradigm. Due to the illustrative nature of our simplified model we do not seek quantitative agreement, but discuss the complementary nature of our approach to the three-dimensional MHD numerical simulations.

Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, WI 53706 (United States); Esquivel, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510 Mexico D.F. (Mexico); Crutcher, R. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

2012-10-01T23:59:59.000Z

299

Observed Microphysical Structure ofObserved Microphysical Structure of MidMid--Level, MixedLevel, Mixed--Phase CloudsPhase Clouds  

E-Print Network (OSTI)

Level, Mixed--Phase CloudsPhase Clouds DOD Center for Geosciences/ Atmospheric Research Colorado State understood, but they cover ~ 22% of globe. Mixed-Phase Structure of Clouds Unknown. 30% are mixed-phase --- i.e. contain both ice and liquid. We need to know ice structure for weather and climate forecasts, e

300

Black carbon enrichment in atmospheric ice particle residuals observed in lower tropospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice crystals was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 ?m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 27% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC containing particles preferentially act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Daniel J.; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Black carbon enrichment in atmospheric ice particle residuals observed in lower trophospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice particles was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 14% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC may act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Dan; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

302

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

SciTech Connect

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

PT May; C Jakob; JH Mather

2004-05-30T23:59:59.000Z

303

Seasonal Variability in Clouds and Radiation at the Manus ARM Site  

SciTech Connect

The Atmospheric Radiation Measurement (ARM) program operates three climate observation stations in the tropical western Pacific region. Two of these sites, located on Manus island in Papua New Guinea and on the island republic of Nauru, have been operating for over five years. This data set provides an opportunity to examine variability in tropical cloudiness on a wide range of time scales. The focus of this study is on the annual cycle. The most obvious manifestation of the annual cycle in this region is the oscillation of monsoon convection between Asia and Australia. The impact of the annual cycle on Manus and Nauru is more subtle; however, analysis of radiation and cloud observations from the Manus and Nauru ARM sites reveals links to the annual monsoon cycle. One such link relates to the proximity of Manus to the Maritime Continent, the collection of islands separating the Pacific and Indian oceans. Convection over the large islands in the maritime continent exhibits a distinct annual cycle. Outflow from large-island convection is shown to modulate the cirrus population over Manus. During neutral or cool ENSO periods, convection over Nauru is relatively suppressed. During such periods, Nauru is shown to exhibit an annual cycle in local convective activity. During the inactive season, cirrus are often found near the tropopause over Nauru. These clouds are not formed directly by the outflow from convection. The seasonality and source of these clouds is also examined. Identifying the source of cirrus observed at Manus and Nauru is important because of the potential dependence of cirrus properties on the source of convection.

Mather, Jim H.

2005-07-01T23:59:59.000Z

304

An Observational and Theoretical Study of Highly Supercooled Altocumulus  

Science Conference Proceedings (OSTI)

Two altocumulus clouds, which formed at a temperature of ?30°C, were sampled using the NCAR King Air aircraft and coincident lidar during the 1986 FIRE cirrus experiment in Wisconsin. The clouds were structurally and thermodynamically similar to ...

Andrew J. Heymsfield; Larry M. Miloshevich; Anthony Slingo; Kenneth Sassen; David O'C. Starr

1991-04-01T23:59:59.000Z

305

On the Climatology of Upper-Layer Clouds  

Science Conference Proceedings (OSTI)

Unique data obtained from a regular aircraft sounding network that operated in the Soviet Union from 1957 through 1963 were used to estimate the potential accuracy of the cirrus cloud cover climatology based on routine ground-based weather ...

Ilia P. Mazin; Svetlana N. Burkovskaya; Elvira T. Ivanova

1993-09-01T23:59:59.000Z

306

Retrieving Properties of Thin Clouds from Solar Aureole Measurements  

Science Conference Proceedings (OSTI)

This paper describes a newly designed Sun and Aureole Measurement (SAM) aureolegraph and the first results obtained with this instrument. SAM measurements of solar aureoles produced by cirrus and cumulus clouds were taken at the Atmospheric ...

J. G. DeVore; A. T. Stair; A. LePage; D. Rall; J. Atkinson; D. Villanucci; S. A. Rappaport; P. C. Joss; R. A. McClatchey

2009-12-01T23:59:59.000Z

307

arm_stm_2007_revercomb_poster_cloud.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Assessment Part 2: Cirrus Radiative Flux Study Using RadarLidarAERI Derived Cloud Properties David Tobin, Lori Borg, David Turner, Robert Holz, Daniel DeSlover, Hank Revercomb,...

308

A Parameterization of the Visible Extinction Coefficient of Ice Clouds in Terms of the Ice/Water Content  

Science Conference Proceedings (OSTI)

This article describes a parameterization of the visible extinction coefficient of cirrus and frontal ice cloud in terms of the ice/water content. The parameterization is based on the discovery that the ice cloud particle size spectra from a ...

C. Martin R. Platt

1997-08-01T23:59:59.000Z

309

Microweve Radiative Transfer through Clouds Composed of Realistically Shaped Ice Crystals. Part II. Remote Sensing of Ice Clouds  

Science Conference Proceedings (OSTI)

This paper presents the results of polarized microwave radiative transfer modeling of cirrus clouds containing five different particle shoes and 18 Gamma size distributions. Upwelling brightness temperatures for tropical and midlatitude winter ...

K. Franklin Evans; Graeme L. Stephens

1995-06-01T23:59:59.000Z

310

accepted to The Astrophysical Journal Letters WHAM Observations of H? from High Velocity Clouds: Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H? line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H? emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

S. L. Tufte; J. D. Wilson; G. J. Madsen; L. M. Haffner; R. J. Reynolds

2002-01-01T23:59:59.000Z

311

Increase of Cloud Droplet Size with Aerosol Optical Depth: An Observational and Modeling Study  

SciTech Connect

Cloud droplet effective radius (DER) is generally negatively correlated with aerosol optical depth (AOD) as a proxy of cloud condensation nuclei. In this study, cases of positive correlation were found over certain portions of the world by analyzing the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products, together with a general finding that DER may increase or decrease with aerosol loading depending on environmental conditions. The slope of the correlation between DER and AOD is driven primarily by water vapor amount, which explains 70% of the variance in our study. Various potential artifacts that may cause the positive relation are investigated including water vapor swelling, partially cloudy, atmospheric dynamics, cloud three-dimensional (3-D) and surface influence effects. None seems to be the primary cause for the observed phenomenon, although a certain degree of influence exists for some of the factors. Analyses are conducted over seven regions around the world representing different types of aerosols and clouds. Only two regions show positive dependence of DER on AOD, near coasts of the Gulf of Mexico and South China Sea, which implies physical processes may at work. Using a 2-D spectral-bin microphysics Goddard Cumulus Ensemble model (GCE) which incorporated a reformulation of the Köhler theory, two possible physical mechanisms are hypothesized. They are related to the effects of slightly soluble organics (SSO) particles and giant CCNs. Model simulations show a positive correlation between DER and AOD, due to a decrease in activated aerosols with an increasing SSO content. Addition of a few giant CCNs also increases the DER. Further investigations are needed to fully understand and clarify the observed phenomenon.

Yuan, Tianle; Li, Zhanqing; Zhang, Renyi; Fan, Jiwen

2008-02-21T23:59:59.000Z

312

TWP-ICE Data from the GEWEX Cloud System Study: Data Integration for Model Evaluation (GCSSDIME)  

DOE Data Explorer (OSTI)

One of the most complete data sets of tropical cirrus and convection observations resulted from the Tropical Warm Pool - International Cloud Experiment (TWP-ICE) in the area around Darwin, Australia. The aim of the experiment is to examine convective cloud systems from their initial stages through the decaying and thin high level cirrus and measure their impact on the environment. The experiment design includes an unprecedented array of soundings and other information to support cloud resolving and other modeling studies as well as a large range of in-situ and remotely sensed observation platforms. A key component of the field campaign is a fleet of aircraft including the Dornier, Dimona, Egrett, Twin Otter, and Proteus. Together, these aircraft collected measurements of cloud properties and the meteorological environment from the planetary boundary layer up to 15 km high. The extensive ground network of cloud sensing radar, lidar and passive instruments are located on a ship and several ground sites throughout the experimental domain. This case study presents data from 19 Jan 2006 to 28 Feb 2006 and covers a region from 25S to 10S latitude and from 125E to 140E longitude.[Copied from http://gcss-dime.giss.nasa.gov/twp-ice/twp-ice.html

313

Validation of Cloud Liquid Water Path Retrievals from SEVIRI Using One Year of CloudNET Observations  

Science Conference Proceedings (OSTI)

The accuracy and precision are determined of cloud liquid water path (LWP) retrievals from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat-8 using 1 yr of LWP retrievals from microwave radiometer (MWR) measurements of ...

R. A. Roebeling; H. M. Deneke; A. J. Feijt

2008-01-01T23:59:59.000Z

314

Improving the representation of low clouds and drizzle in the ECMWF model based on ARM observations from the Azores.  

Science Conference Proceedings (OSTI)

In this study, the representation of marine boundary layer cloud is investigated in the ECMWF model using observations from the Atmospheric Radiation Measurement (ARM) mobile facility deployment to Graciosa Island in the North Atlantic. Systematic ...

Maike Ahlgrimm; Richard Forbes

315

Cloud-Resolving Hurricane Initialization and Prediction through Assimilation of Doppler Radar Observations with an Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

This study explores the assimilation of Doppler radar radial velocity observations for cloud-resolving hurricane analysis, initialization, and prediction with an ensemble Kalman filter (EnKF). The case studied is Hurricane Humberto (2007), the ...

Fuqing Zhang; Yonghui Weng; Jason A. Sippel; Zhiyong Meng; Craig H. Bishop

2009-07-01T23:59:59.000Z

316

Importance of Accurate Liquid Water Path for Estimation of Solar Radiation in Warm Boundary Layer Clouds: An Observational Study  

Science Conference Proceedings (OSTI)

A 1-yr observational study of overcast boundary layer stratus at the U.S. Department of Energy Atmospheric Radiation Measurement Program Southern Great Plains site illustrates that surface radiation has a higher sensitivity to cloud liquid water ...

Manajit Sengupta; Eugene E. Clothiaux; Thomas P. Ackerman; Seiji Kato; Qilong Min

2003-09-01T23:59:59.000Z

317

An Artificial Neural Network model to reduce false alarms in satellite precipitation products using MODIS and CloudSat observations  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectro-radiometer (MODIS) instrument aboard the NASA Earth Observing System (EOS) Aqua and Terra platform with 36 spectral bands provides valuable information about cloud microphysical characteristics and therefore ...

Nasrin Nasrollahi; Kuolin Hsu; Soroosh Sorooshian

318

Ocean Frontal Effects on the Vertical Development of Clouds over the Western North Pacific: In Situ and Satellite Observations  

Science Conference Proceedings (OSTI)

A suite of shipboard and satellite observations are analyzed and synthesized to investigate the three-dimensional structure of clouds and influences from sea surface temperature fronts over the western North Pacific. Sharp transitions are ...

Hiroki Tokinaga; Youichi Tanimoto; Shang-Ping Xie; Takeaki Sampe; Hiroyuki Tomita; Hiroshi Ichikawa

2009-08-01T23:59:59.000Z

319

Comparison of High-Cloud Characteristics as Estimated by Selected Spaceborne Observations and Ground-Based Lidar Datasets  

Science Conference Proceedings (OSTI)

The characterization of high clouds as performed from selected spaceborne observations is assessed in this article by employing a number of worldwide ground-based lidar multiyear datasets as reference. Among the latter, the ground lidar ...

Artemio Plana-Fattori; Gérard Brogniez; Patrick Chervet; Martial Haeffelin; Olga Lado-Bordowsky; Yohann Morille; Frédéric Parol; Jacques Pelon; Antoine Roblin; Genevičve Sčze; Claudia Stubenrauch

2009-06-01T23:59:59.000Z

320

Cloud Liquid Water Path from Satellite-Based Passive Microwave Observations: A New Climatology over the Global Oceans  

Science Conference Proceedings (OSTI)

This work describes a new climatology of cloud liquid water path (LWP), termed the University of Wisconsin (UWisc) climatology, derived from 18 yr of satellite-based passive microwave observations over the global oceans. The climatology is based ...

Christopher W. O’Dell; Frank J. Wentz; Ralf Bennartz

2008-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Development of a Detailed Microphysics Cirrus Model Tracking Aerosol Particles’ Histories for Interpretation of the Recent INCA Campaign  

Science Conference Proceedings (OSTI)

Cirrus clouds play an important role in the earth’s energy balance. To quantify their impact, information is needed on their microstructure and more precisely on the number and size of the ice crystals. With the anthropogenic activity, more and ...

Marie Monier; Wolfram Wobrock; Jean-François Gayet; Andrea Flossmann

2006-02-01T23:59:59.000Z

322

The Occurrence of Particle Size Distribution Bimodality in Midlatitude Cirrus as Inferred from Ground-Based Remote Sensing Data  

Science Conference Proceedings (OSTI)

Data collected in midlatitude cirrus clouds by instruments on jet aircraft typically show particle size distributions that have distinct distribution modes in both the 10–30-?m maximum dimension (D) size range and the 200–300-?m D size range or ...

Yang Zhao; Gerald G. Mace; Jennifer M. Comstock

2011-06-01T23:59:59.000Z

323

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

E-Print Network (OSTI)

simulation that is in the ice-phase. Note that the y-axis isradiative properties of ice and mixed-phase clouds. Quart.include liquid-phase only, ice-phase only, and mixed-phase.

Klein, Stephen A.

2009-01-01T23:59:59.000Z

324

Retrieval of Cirrus Microphysical Properties with a Suite of Algorithms for Airborne and Spaceborne Lidar, Radar, and Radiometer Data  

Science Conference Proceedings (OSTI)

Algorithms are developed to convert data streams from multiple airborne and spaceborne remote sensors into layer-averaged cirrus bulk microphysical properties. Radiometers such as the Moderate-Resolution Imaging Spectroradiometer (MODIS) observe ...

Yuying Zhang; Gerald G. Mace

2006-12-01T23:59:59.000Z

325

AMI OBSERVATIONS OF THE ANOMALOUS MICROWAVE EMISSION IN THE PERSEUS MOLECULAR CLOUD  

SciTech Connect

We present observations of the known anomalous microwave emission region, G159.6-18.5, in the Perseus molecular cloud at 16 GHz performed with the Arcminute Microkelvin Imager Small Array. These are the highest angular resolution observations of G159.6-18.5 at microwave wavelengths. By combining these microwave data with infrared observations between 5.8 and 160 {mu}m from the Spitzer Space Telescope, we investigate the existence of a microwave-infrared correlation on angular scales of {approx}2'. We find that the overall correlation appears to increase toward shorter infrared wavelengths, which is consistent with the microwave emission being produced by electric dipole radiation from small, spinning dust grains. We also find that the microwave-infrared correlation peaks at 24 {mu}m (6.7{sigma}), suggesting that the microwave emission is originating from a population of stochastically heated small interstellar dust grains rather than polycyclic aromatic hydrocarbons.

Tibbs, C. T. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Scaife, A. M. M. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Dickinson, C.; Davies, R. D.; Davis, R. J.; Watson, R. A. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Paladini, R. [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Grainge, K. J. B., E-mail: ctibbs@ipac.caltech.edu [Astrophysics Group, Cavendish Laboratory, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2013-05-10T23:59:59.000Z

326

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

Science Conference Proceedings (OSTI)

The evaluation of the diurnal cycle of cloud amount (CA) and cloud condensed water path (CWP) as predicted by climate models receives relatively little attention, mostly because of the lack of observational data capturing the diurnal cycle of ...

R. A. Roebeling; E. van Meijgaard

2009-04-01T23:59:59.000Z

327

A Land and Ocean Microwave Cloud Classification Algorithm Derived from AMSU-A and -B, Trained Using MSG-SEVIRI Infrared and Visible Observations  

Science Conference Proceedings (OSTI)

A statistical cloud classification and cloud mask algorithm is developed based on Advanced Microwave Sounding Unit (AMSU-A and -B) microwave (MW) observations. The visible and infrared data from the Meteosat Third Generation-Spinning Enhanced ...

Filipe Aires; Francis Marquisseau; Catherine Prigent; Genevičve Sčze

2011-08-01T23:59:59.000Z

328

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

SciTech Connect

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

Liu, X; Ghan, SJ; Xie, S

2007-04-01T23:59:59.000Z

329

A Comparison of TWP-ICE Observational Data with Cloud-Resolving Model Results  

SciTech Connect

Observations made during the TWP-ICE campaign are used to drive and evaluate thirteen cloud-resolving model simulations with periodic lateral boundary conditions. The simulations employ 2D and 3D dynamics, one- and two-moment microphysics, several variations on large-scale forcing, and the use of observationally derived aerosol properties to prognose droplet numbers. When domain means are averaged over a 6-day active monsoon period, all simulations reproduce observed surface precipitation rate but not its structural distribution. Simulated fractional areas covered by convective and stratiform rain are uncorrelated with one another, and are both variably overpredicted by up to a factor of {approx}2. Stratiform area fractions are strongly anticorrelated with outgoing longwave radiation (OLR) but are negligibly correlated with ice water path (IWP), indicating that ice spatial distribution controls OLR more than mean IWP. Overpredictions of OLR tend to be accompanied by underpredictions of reflected shortwave radiation (RSR). When there are two simulations differing only in microphysics scheme or large-scale forcing, the one with smaller stratiform area tends to exhibit greater OLR and lesser RSR by similar amounts. After {approx}10 days, simulations reach a suppressed monsoon period with a wide range of mean precipitable water vapor, attributable in part to varying overprediction of cloud-modulated radiative flux divergence compared with observationally derived values. Differences across the simulation ensemble arise from multiple sources, including dynamics, microphysics, and radiation treatments. Close agreement of spatial and temporal averages with observations may not be expected, but the wide spreads of predicted stratiform fraction and anticorrelated OLR indicate a need for more rigorous observation-based evaluation of the underlying micro- and macrophysical properties of convective and stratiform structures.

Fridlind, A. M.; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Grabowski, Wojciech W.; Hill, A.; Jones, T. R.; Khaiyer, M. M.; Liu, G.; Minnis, Patrick; Morrison, H.; Nguyen, L.; Park, S.; Petch, Jon C.; Pinty, Jean-Pierre; Schumacher, Courtney; Shipway, Ben; Varble, A. C.; Wu, Xiaoqing; Xie, Shaocheng; Zhang, Minghua

2012-03-13T23:59:59.000Z

330

Aggregation of Ice Crystals in Cirrus  

Science Conference Proceedings (OSTI)

Results are given from analysis of the aggregation of thick plate, columnar, and bullet rosette ice crystals in cirrus. Data were obtained from PMS 2D-C images, oil coated slides, and aircraft meteorological measurements. Crystal size ranged from ...

Masahiro Kajikawa; Andrew J. Heymsfield

1989-10-01T23:59:59.000Z

331

Contrails and Induced Cirrus: Optics and Radiation  

Science Conference Proceedings (OSTI)

This paper summarizes the assessment of the current state of knowledge, areas of uncertainties, and recommendations for future efforts, regarding the optical and radiative properties of contrails and contrail cirrus, which have been reported in ...

Ping Yang; Gang Hong; Andrew E. Dessler; Steve S. C. Ou; Kuo-Nan Liou; Patrick Minnis; Harshvardhan

2010-04-01T23:59:59.000Z

332

Observational Study of the Entrainment-Mixing Process in Warm Convective Clouds  

Science Conference Proceedings (OSTI)

Thermodynamical and microphysical measurements collected in convective clouds are examined within the frame of the homogeneous/inhomogeneous mixing concept, to determine how entrainment-mixing processes affect cloud droplets, their number ...

Frédéric Burnet; Jean-Louis Brenguier

2007-06-01T23:59:59.000Z

333

Ship-Based Observations of the Diurnal Cycle of Southeast Pacific Marine Stratocumulus Clouds and Precipitation  

Science Conference Proceedings (OSTI)

The diurnal cycle of marine stratocumulus in cloud-topped boundary layers is examined using ship-based meteorological data obtained during the 2008 VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx). The high temporal and ...

Casey D. Burleyson; Simon P. de Szoeke; Sandra E. Yuter; Matt Wilbanks; W. Alan Brewer

334

On the Modification Potential of Illinois Summertime Convective Clouds, with Comparisons to Florida and FACE Observations  

Science Conference Proceedings (OSTI)

The potential for enhancing rain output over central Illinois through modification of summertime convective clouds was investigated by use of model predictions of cumulus growth, as well as direct, internal measurements of cloud physical ...

Victor Wiggert; Robert I. Sax; Ronald L. Holle

1982-09-01T23:59:59.000Z

335

Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment  

Science Conference Proceedings (OSTI)

Clouds and the Earth's Radiant Energy System (CERES) is an investigation to examine the role of cloud/radiation feedback in the Earth's climate system. The CERES broadband scanning radiometers are an improved version of the Earth Radiation Budget ...

Bruce A. Wielicki; Bruce R. Barkstrom; Edwin F. Harrison; Robert B. Lee III; G. Louis Smith; John E. Cooper

1996-05-01T23:59:59.000Z

336

Microphysical and Radar Observations of Seeded and Nonseeded Continental Cumulus Clouds  

Science Conference Proceedings (OSTI)

Controlled cloud seeding experiments were conducted near Bethlehem, South Africa during the summer of 1984–85. The experimental unit was the semi-isolated cumulus congestus cloud. Microphysical measurements were obtained by three instrumented ...

T. W. Krauss; R. T. Bruintjes; J. Verlinde

1987-05-01T23:59:59.000Z

337

The Plane-Parallel Albedo Bias of Liquid Clouds from MODIS Observations  

Science Conference Proceedings (OSTI)

The authors present the global plane-parallel shortwave albedo bias of liquid clouds for two months, July 2003 and January 2004. The cloud optical properties necessary to perform the bias calculations come from the operational Moderate Resolution ...

Lazaros Oreopoulos; Robert F. Cahalan; Steven Platnick

2007-10-01T23:59:59.000Z

338

Observational and Theoretical Studies of Solar Radiation in Arctic Stratus Clouds  

Science Conference Proceedings (OSTI)

A series of clouds-radiation experiments was carried out in June 1980 in Arctic stratus clouds occurring over the Beaufort Sea using the NCAR Electra aircraft. This paper is an analysis of the hemispheric radiation fields obtained with Eppley ...

G. F. Herman; J. A. Curry

1984-01-01T23:59:59.000Z

339

Cloud-Resolving Satellite Data Assimilation: Information Content of IR Window Observations and Uncertainties in Estimation  

Science Conference Proceedings (OSTI)

This study addresses the problem of four-dimensional (4D) estimation of a cloudy atmosphere on cloud-resolving scales using satellite remote sensing measurements. The motivation is to develop a methodology for accurate estimation of cloud ...

T. Vukicevic; M. Sengupta; A. S. Jones; T. Vonder Haar

2006-03-01T23:59:59.000Z

340

Structure and Evolution of North Australian Cloud Lines Observed during AMEX Phase I  

Science Conference Proceedings (OSTI)

North Australian Clouds Lines are distinctive, squall-line phenomena that occur in easterly flow across northern Australia. Three basic types have been identified, ranging from a long, narrow line of convective clouds (Type 1) to a severe squall ...

Wasyl Drosdowsky; Greg J. Holland; Roger K. Smith

1989-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Scale Dependence of the Thermodynamic Forcing of Tropical Monsoon Clouds: Results from TRMM Observations  

Science Conference Proceedings (OSTI)

Clouds exert a thermodynamic forcing on the ocean–atmosphere column through latent heating, owing to the production of rain, and through cloud radiative forcing, owing to the absorption of terrestrial infrared energy and the reflection of solar ...

Eric M. Wilcox; V. Ramanathan

2001-04-01T23:59:59.000Z

342

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

SciTech Connect

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

Howard Barker; Jason Cole

2012-05-17T23:59:59.000Z

343

Parameterization of ice cloud radiative properties and its application to the potential climatic importance of mixed-phase clouds  

SciTech Connect

It is often assumed, in modeling and radiation budget simulation, that clouds below the cirrus level are entirely in the liquid phase. There is substantive evidence from observations that low and middle clouds are often of mixed phase. Using a light-scattering program for hexagonal crystals, the authors update a parameterization of the radiative properties of ice clouds from an earlier study and use the new parameterization to investigate the role of mixed-phase clouds in three areas: (i) the interpretation of ISCCP optical depth, (ii) the simulation of the earth radiation budget, and (iii) the sensitivity of a simple radiative-convective model to an increase in CO{sub 2}. In all cases, mixed-phase clouds are shown to have the potential to significantly modify the results obtained using liquid phase clouds. A precise quantification is not yet possible as the dependence of the fraction of ice and liquid water is mixed-phase clouds on atmospheric properties, and the way in which the ice and liquid water are mixed, are not known with sufficient detail. 43 refs., 17 figs., 2 tabs.

Sun, Z.; Shine, K.P. [Univ. of Reading (United Kingdom)] [Univ. of Reading (United Kingdom)

1995-07-01T23:59:59.000Z

344

Observations and Modeling of Shallow Convective Clouds: Implications for the Indirect Aerosol Effects  

NLE Websites -- All DOE Office Websites (Extended Search)

Observations Observations and Modeling of Shallow Convective Clouds: Implications for the Indirect Aerosol Effects Sylwester Arabas 1 , Joanna Slawinska 1 , Wojciech Grabowski 2 , Hugh Morrison 2 , Hanna Pawlowska 1 1 : Institute of Geophysics, University of Warsaw, Poland 2 : National Center for Atmospheric Research, Boulder, Colorado, USA 348 constants for reference state and lateral boundary conditions 349 ibcx=icyx 350 ibcy=icyy*j3 351 ibcz=icyz 352 irlx=irelx 353 irly=irely*j3 354 irdbc=0 355 fcr0=fcr0*icorio 356 itdl=0 357 tdt=40.*3600. 358 u0tdl=u00 359 360 361 constants for thermodynamics 362 c bv=sqrt(st*g) 363 bv=st 364 st=bv**2/g 365 cp=3.5*rg 366 cap=rg/cp 367 pr00=rg*rh00*tt00

345

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

SciTech Connect

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

Somerville, Richard

2013-08-22T23:59:59.000Z

346

Improvements of a Mixed-Phase Cloud Scheme Using Aircraft Observations  

Science Conference Proceedings (OSTI)

To improve the quality of forecasts of mixed-phase clouds in winter storms, some aspects of a cloud scheme are examined in detail. Modifications to the basic formalism and specification of selected parameters of the cloud model are studied, and ...

André Tremblay; Paul A. Vaillancourt; Stewart G. Cober; Anna Glazer; George A. Isaac

2003-04-01T23:59:59.000Z

347

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

Science Conference Proceedings (OSTI)

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

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

2010-05-12T23:59:59.000Z

348

Insights into Cloud-Top Height and Dynamics from the Seasonal Cycle of Cloud-Top Heights Observed by MISR in the West Pacific Region  

Science Conference Proceedings (OSTI)

The connection between environmental stability and the height of tropical deep convective clouds is analyzed using stereo cloud height data from the Multiangle Imaging Spectroradiometer (MISR), focusing on the seasonal cycle of clouds over the ...

Jung Hyo Chae; Steven C. Sherwood

2010-01-01T23:59:59.000Z

349

Droplet Growth in Warm Water Clouds Observed by the A-Train. Part I: Sensitivity Analysis of the MODIS-Derived Cloud Droplet Sizes  

Science Conference Proceedings (OSTI)

This study examines the sensitivity of the retrieved cloud droplet radii (CDR) to the vertical inhomogeneity of droplet radii, including the existence of a drizzle mode in clouds. The focus of this study is warm water-phase clouds. Radiative ...

Takashi Y. Nakajima; Kentaroh Suzuki; Graeme L. Stephens

2010-06-01T23:59:59.000Z

350

Remote Sounding of High Clouds. III: Monte Carlo Calculations of Multiple-Scattered Lidar Returns  

Science Conference Proceedings (OSTI)

Monte Carlo calculations of multiple-scattered contributions to the total energy received in a lidar beam have been made for a representative cirrus ice-cloud scattering phase function. The phase function is varied arbitrarily near the back ...

C. M. R. Platt

1981-01-01T23:59:59.000Z

351

Microwave Radiative Transfer through Clouds Composed of Realistically Shaped Ice Crystals. Part I. Single Scattering Properties  

Science Conference Proceedings (OSTI)

This paper presents the results of a detailed study of the microwave single scattering properties of ice crystals expected in cirrus clouds. The discrete dipole approximation is used to compute scattering quantities of particles ranging in size ...

K. Franklin Evans; Graeme L. Stephens

1995-06-01T23:59:59.000Z

352

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

SciTech Connect

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

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

2007-12-14T23:59:59.000Z

353

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

E-Print Network (OSTI)

ice nucleation parameterization slightly improves the model performance for low-level mixed-phase ice loss by enhancing ice-albedo feedbacks [Kay et al., 2008]. Arctic clouds are often mixed-phase (i-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its

354

Feasibility of Determining Cloud-Top Heights Using the Backscattered Ultraviolet Satellite Observation Technique  

Science Conference Proceedings (OSTI)

A technique for determining cloud-top height by means of backscattered ultraviolet (BUV) solar radiation is presented. Cloud-top heights can be inferred using this technique if both the BUV radiance and its degree of polarization are measured by ...

Tadashi Aruga; Kaichi Maeda; Donald F. Heath

1984-05-01T23:59:59.000Z

355

Observations of Cloud, Radiation, and Surface Forcing in the Equatorial Eastern Pacific  

Science Conference Proceedings (OSTI)

In this paper the authors report on a study of cloud and surface flux processes in the tropical eastern Pacific Ocean based on a series of ship-based cloud and flux measurements made during fall (1999–2002) and spring (2000–02) maintenance ...

C. W. Fairall; Taneil Uttal; Duane Hazen; Jeffrey Hare; Meghan F. Cronin; Nicholas Bond; Dana E. Veron

2008-02-01T23:59:59.000Z

356

WHAM Observations of H-alpha Emission from High Velocity Clouds in the M, A, and C Complexes  

E-Print Network (OSTI)

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present results including clear detections of H-alpha emission from all three complexes with intensities ranging from 0.06 R to 0.20 R. In every observed direction where there is significant high velocity H I gas seen in the 21 cm line we have found associated ionized hydrogen emitting the H-alpha line. The velocities of the H-alpha and 21 cm emission are well correlated in every case except one, but the intensities are not correlated. There is some evidence that the ionized gas producing the H-alpha emission envelopes the 21 cm emitting neutral gas but the H-alpha "halo", if present, is not large. If the H-alpha emission arises from the photoionization of the H I clouds, then the implied Lyman continuum flux F_{LC} at the location of the clouds ranges from 1.3 to 4.2 x 10^5 photons cm^{-2} s^{-1}. If, on the other hand, the ionization is due to a shock arising from the collision of the high-velocity gas with an ambient medium in the halo, then the density of the pre-shocked gas can be constrained. We have also detected the [S II] 6716 angstrom line from the M I cloud and have evidence that the [S II] to H-alpha ratio varies with location on the cloud.

S. L. Tufte; R. J. Reynolds; L. M. Haffner

1998-07-15T23:59:59.000Z

357

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

Science Conference Proceedings (OSTI)

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

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

2012-12-01T23:59:59.000Z

358

A Climatology of Warm-Season Cloud Patterns over East Asia Based on GMS Infrared Brightness Temperature Observations  

Science Conference Proceedings (OSTI)

In the present study, hourly infrared (IR) brightness temperatures observed by the Geostationary Meteorological Satellite (GMS) over the region 20°–40°N, 95°–145°E in May–August 1998–2001 are used to compile a climatology of warm-season cloud/...

Chung-Chieh Wang; George Tai-Jen Chen; Richard E. Carbone

2004-07-01T23:59:59.000Z

359

Cloud Cover over the South Pole from Visual Observations, Satellite Retrievals, and Surface-Based Infrared Radiation Measurements  

Science Conference Proceedings (OSTI)

Estimates of cloud cover over the South Pole are presented from five different data sources: routine visual observations (1957–2004; Cvis), surface-based spectral infrared (IR) data (2001; CPAERI), surface-based broadband IR data (1994–2003; Cpyr)...

Michael S. Town; Von P. Walden; Stephen G. Warren

2007-02-01T23:59:59.000Z

360

Phenomenological Description of Tropical Clouds Using CloudSat Cloud Classification  

Science Conference Proceedings (OSTI)

Two years of tropical oceanic cloud observations are analyzed using the operational CloudSat cloud classification product and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar. Relationships are examined between ...

Ali Behrangi; Terry Kubar; Bjorn Lambrigtsen

2012-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

WHAM Observations of H$\\alpha$ Emission from High Velocity Clouds in the M, A, and C Complexes  

E-Print Network (OSTI)

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present results including clear detections of H-alpha emission from all three complexes with intensities ranging from 0.06 R to 0.20 R. In every observed direction where there is significant high velocity H I gas seen in the 21 cm line we have found associated ionized hydrogen emitting the H-alpha line. The velocities of the H-alpha and 21 cm emission are well correlated in every case except one, but the intensities are not correlated. There is some evidence that the ionized gas producing the H-alpha emission envelopes the 21 cm emitting neutral gas but the H-alpha "halo", if present, is not large. If the H-alpha emission arises from the photoionization of the H I clouds, then the implied Lyman continuum flux F_{LC} at the location of the clouds ranges from 1.3 to 4.2 x 10^5 photons...

Tufte, S L; Haffner, L M

1998-01-01T23:59:59.000Z

362

Observations of ground-state OH in the Large Magellanic Cloud  

E-Print Network (OSTI)

We have carried out a series of observations of the 1665- and 1667-MHz transitions of the 2Pi_3/2, J=3/2 OH ground state towards six selected HII regions in the Large Magellanic Cloud (IRAS 05011-6815 and MRC 0510-689, 0513-694B, 0539-691, 0540-696B, 0540-697A) using the Australia Telescope Compact Array. The study has provided the first accurate positions for known 1665- and 1667-MHz OH masers as well as detecting several new masers. The regions all contain H_2O or CH_3OH masers but OH masers were detected in only four. The 1.6-GHz continuum emission was also imaged to investigate its spatial relationship to the associated OH maser. Although some masers are close to compact continuum components, in other cases they are near the continuum distribution boundaries and perhaps have been created as a result of the HII region interacting with the surrounding interstellar medium.

K. J. Brooks; J. B. Whiteoak

1997-10-16T23:59:59.000Z

363

VERY LARGE ARRAY OBSERVATIONS OF THE INFRARED DARK CLOUD G19.30+0.07  

SciTech Connect

We present Very Large Array observations of ammonia (NH{sub 3}) (1,1), (2,2), and dicarbon sulfide (CCS) (2{sub 1}-1{sub 0}) emission toward the infrared dark cloud (IRDC) G19.30+0.07 at {approx}22 GHz. The NH{sub 3} emission closely follows the 8 {mu}m extinction. The NH{sub 3} (1,1) and (2,2) lines provide diagnostics of the temperature and density structure within the IRDC, with typical rotation temperatures of {approx}10-20 K and NH{sub 3} column densities of {approx}10{sup 15} cm{sup -2}. The estimated total mass of G19.30+0.07 is {approx}1130 M{sub sun}. The cloud comprises four compact NH{sub 3} clumps of mass {approx}30-160 M{sub sun}. Two coincide with 24 {mu}m emission, indicating heating by protostars, and show evidence of outflow in the NH{sub 3} emission. We report a water maser associated with a third clump; the fourth clump is apparently starless. A non-detection of 8.4 GHz emission suggests that the IRDC contains no bright H II regions and places a limit on the spectral type of an embedded zero-age main-sequence star to early-B or later. From the NH{sub 3} emission, we find that G19.30+0.07 is composed of three distinct velocity components or 'subclouds'. One velocity component contains the two 24 {mu}m sources and the starless clump, another contains the clump with the water maser, while the third velocity component is diffuse, with no significant high-density peaks. The spatial distribution of NH{sub 3} and CCS emission from G19.30+0.07 is highly anti-correlated, with the NH{sub 3} predominantly in the high-density clumps and the CCS tracing lower-density envelopes around those clumps. This spatial distribution is consistent with theories of evolution for chemically young low-mass cores, in which CCS has not yet been processed to other species and/or depleted in high-density regions.

Devine, K. E.; Churchwell, E. [Department of Astronomy, University of Wisconsin, 475 N. Charter Street, Madison, WI 53703 (United States); Chandler, C. J.; Borg, K. J. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Brogan, C.; Indebetouw, R. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Shirley, Y., E-mail: kdevine@collegeofidaho.edu [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)

2011-05-20T23:59:59.000Z

364

Combined Observational and Model Investigations of the Z–LWC Relationship in Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

In situ measurements indicate the complexity and nonunique character of radar reflectivity–liquid water content (Z–LWC) relationships in stratocumulus and cumulus clouds. Parameters of empirical (statistical) Z–LWC dependences vary within a wide ...

A. Khain; M. Pinsky; L. Magaritz; O. Krasnov; H. W. J. Russchenberg

2008-02-01T23:59:59.000Z

365

Short-Term Performance of MM5 with Cloud-Cover Assimilation from Satellite Observations  

Science Conference Proceedings (OSTI)

This study investigates the extent to which assimilating high-resolution remotely sensed cloud cover into the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) provides an ...

Ismail Yucel; W. James Shuttleworth; X. Gao; S. Sorooshian

2003-08-01T23:59:59.000Z

366

Temporal Changes in the Observed Relationship between Cloud Cover and Surface Air Temperature  

Science Conference Proceedings (OSTI)

The relationship between cloud cover and near-surface air temperature and its decadal changes are examined using the hourly synoptic data for the past four to six decades from five regions of the Northern Hemisphere: Canada, the United States, ...

Bomin Sun; Pavel Ya Groisman; Raymond S. Bradley; Frank T. Keimig

2000-12-01T23:59:59.000Z

367

Cloud Variability over the Indian Monsoon Region as Observed from Satellites  

Science Conference Proceedings (OSTI)

This study focuses on documenting the seasonal progression of the Asian monsoon by analyzing clouds and convection in the pre-, peak-, and postmonsoon seasons. This effort was possible as a result of the movement of Meteosat-5 over the Indian ...

Margaret M. Wonsick; Rachel T. Pinker; Yves Govaerts

2009-09-01T23:59:59.000Z

368

Cloud Phase Determination Using Ground-Based AERI Observations at SHEBA  

Science Conference Proceedings (OSTI)

A new technique for ascertaining the thermodynamic cloud phase from high-spectral-resolution ground-based infrared measurements made by the Atmospheric Emitted Radiance Interferometer (AERI) is presented. This technique takes advantage of the ...

D. D. Turner; S. A. Ackerman; B. A. Baum; H. E. Revercomb; P. Yang

2003-06-01T23:59:59.000Z

369

Multiwavelength Observations of a Developing Cloud System: The FIRE II 26 November 1991 Case Study  

Science Conference Proceedings (OSTI)

Simultaneous multiwavelength measurements of a developing cloud system were obtained by NOAA Doppler lidar, Doppler radar, Fourier transform infrared interferometer, and microwave and infrared radiometers on 26 November 1991. The evolution of the ...

J. M. Intrieri; W. L. Eberhard; T. Uttal; J. A. Shaw; J. B. Snider; Y. Han; B. W. Orr; S. Y. Matrosov

1995-12-01T23:59:59.000Z

370

AMSU-B Observations of Mixed-Phase Clouds over Land  

Science Conference Proceedings (OSTI)

Measurements from passive microwave satellite instruments such as the Advanced Microwave Sounding Unit B (AMSU-B) are sensitive to both liquid and ice cloud particles. Radiative transfer modeling is exploited to simulate the response of the AMSU-...

M. N. Deeter; J. Vivekanandan

2005-01-01T23:59:59.000Z

371

Further Observations of the Production of Ice Particles in Clouds by Aircraft  

Science Conference Proceedings (OSTI)

Evidence is presented for the production of high concentrations of rather uniformly-sized ice crystals in a supercooled stratus cloud by a commercial, turbine, propeller-driven aircraft.

Arthur L. Rangno; Peter V. Hobbs

1984-06-01T23:59:59.000Z

372

Investigation of Regional and Seasonal Variations in Marine Boundary Layer Cloud Properties from MODIS Observations  

Science Conference Proceedings (OSTI)

To aid in understanding the role that marine boundary layer (MBL) clouds play in climate and assist in improving their representations in general circulation models (GCMs), their long-term microphysical and macroscale characteristics are ...

Michael P. Jensen; Andrew M. Vogelmann; William D. Collins; Guang J. Zhang; Edward P. Luke

2008-10-01T23:59:59.000Z

373

Distributions of Liquid, Vapor, and Ice in an Orographic Cloud from Field Observations  

Science Conference Proceedings (OSTI)

The phase distribution of the water mass of a cold orographic cloud into vapor, liquid, and ice is calculated from measurements made from an instrumented aircraft. The vapor values are calculated from thermodynamic measurements, and the liquid is ...

Taneil Uttal; Robert M. Rauber; Lewis O. Grant

1988-04-01T23:59:59.000Z

374

Radar Observations of Transport and Diffusion in Clouds and Precipitation Using TRACIR  

Science Conference Proceedings (OSTI)

A remote-sensing technique called TRACIR (tracking air with circular-polarization radar) was developed recently for studying air-parcel trajectories in clouds. The technique uses a dual-circular-polarization radar to detect microwave chaff fibers ...

Brooks E. Martner; Robert A. Kropfli; John D. Marwitz

1992-06-01T23:59:59.000Z

375

Comparisons between Model Forecast and Observed Boundary Layer Profiles and Related Comments on Cloud Prediction  

Science Conference Proceedings (OSTI)

In this study comparisons are made between Met Office mesoscale model boundary layer profiles, and radiosonde data collected in the central United Kingdom during three intensive boundary layer cloud experiments. Significant differences between ...

J. D. Price; M. R. Bush

2004-12-01T23:59:59.000Z

376

Numerical Simulations of Observed Arctic Stratus Clouds Using a Second-Order Turbulence Closure Model  

Science Conference Proceedings (OSTI)

A high-resolution one-dimensional version of a second-order turbulence closure radiative-convective model, developed at Los Alamos National Laboratory, is used to simulate the interactions among turbulence, radiation, and bulk cloud parameters in ...

W. S. Smith; C-Y. J. Kao

1996-01-01T23:59:59.000Z

377

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

SciTech Connect

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

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

2007-09-30T23:59:59.000Z

378

Forecasting Cloud Cover and Atmospheric Seeing for Astronomical Observing: Application and Evaluation of the Global Forecast System  

E-Print Network (OSTI)

To explore the issue of performing a non-interactive numerical weather forecast with an operational global model in assist of astronomical observing, we use the Xu-Randall cloud scheme and the Trinquet-Vernin AXP seeing model with the global numerical output from the Global Forecast System to generate 3-72h forecasts for cloud coverage and atmospheric seeing, and compare them with sequence observations from 9 sites from different regions of the world with different climatic background in the period of January 2008 to December 2009. The evaluation shows that the proportion of prefect forecast of cloud cover forecast varies from ~50% to ~85%. The probability of cloud detection is estimated to be around ~30% to ~90%, while the false alarm rate is generally moderate and is much lower than the probability of detection in most cases. The seeing forecast has a moderate mean difference (absolute mean difference <0.3" in most cases) and root-mean-square-error or RMSE (0.2"-0.4" in most cases) comparing with the obs...

Ye, Q -z

2010-01-01T23:59:59.000Z

379

Retrieval of cloud properties using CALIPSO Imaging Infrared Radiometer. Part II: effective diameter and ice water path  

Science Conference Proceedings (OSTI)

The paper describes the version 3 Level 2 operational analysis of the Imaging Infrared Radiometer (IIR) data collected in the framework of the CALIPSO mission to retrieve cirrus cloud effective diameter and ice water path in synergy with the ...

Anne Garnier; Jacques Pelon; Philippe Dubuisson; Ping Yang; Michaël Faivre; Olivier Chomette; Nicolas Pascal; Pat Lucker; Tim Murray

380

Evaluation of Several A-Train Ice Cloud Retrieval Products with In Situ Measurements Collected during the SPARTICUS Campaign  

Science Conference Proceedings (OSTI)

In this study several ice cloud retrieval products that utilize active and passive A-Train measurements are evaluated using in situ data collected during the Small Particles in Cirrus (SPARTICUS) field campaign. The retrieval datasets include ice ...

Min Deng; Gerald G. Mace; Zhien Wang; R. Paul Lawson

2013-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Cloud properties derived from two lidars over the ARM SGP site  

Science Conference Proceedings (OSTI)

[1] Active remote sensors such as lidars or radars can be used with other data to quantify the cloud properties at regional scale and at global scale (Dupont et al., 2009). Relative to radar, lidar remote sensing is sensitive to very thin and high clouds but has a significant limitation due to signal attenuation in the ability to precisely quantify the properties of clouds with a 20 cloud optical thickness larger than 3. In this study, 10-years of backscatter lidar signal data are analysed by a unique algorithm called STRucture of ATmosphere (STRAT, Morille et al., 2007). We apply the STRAT algorithm to data from both the collocated Micropulse lidar (MPL) and a Raman lidar (RL) at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site between 1998 and 2009. Raw backscatter lidar signal is processed and 25 corrections for detector deadtime, afterpulse, and overlap are applied. (Campbell et al.) The cloud properties for all levels of clouds are derived and distributions of cloud base height (CBH), top height (CTH), physical cloud thickness (CT), and optical thickness (COT) from local statistics are compared. The goal of this study is (1) to establish a climatology of macrophysical and optical properties for all levels of clouds observed over the ARM SGP site 30 and (2) to estimate the discrepancies induced by the two remote sensing systems (pulse energy, sampling, resolution, etc.). Our first results tend to show that the MPLs, which are the primary ARM lidars, have a distinctly limited range where all of these cloud properties are detectable, especially cloud top and cloud thickness, but even actual cloud base especially during summer daytime period. According to the comparisons between RL and MPL, almost 50% of situations show a signal to noise ratio too low (smaller than 3) for the MPL in order to detect clouds higher than 7km during daytime period in summer. Consequently, the MPLderived annual cycle of cirrus cloud base (top) altitude is biased low, especially for daylight periods, compared with those derived from the RL data, which detects 5 cloud base ranging from 7.5 km in winter to 9.5 km in summer (and tops ranging from 8.6 to 10.5 km). The optically thickest cirrus clouds (COT>0.3) reach 50% of the total population for the Raman lidar and only 20% for the Micropulse lidar due to the difference of pulse energy and the effect of solar irradiance contamination. A complementary study using the cloud fraction 10 derived from the Micropulse lidar for clouds below 5 km and from the Raman lidar for cloud above 5 km allows for better estimation of the total cloud fraction between the ground and the top of the atmosphere. This study presents the diurnal cycle of cloud fraction for each season in comparisons with the Long et al. (2006) cloud fraction calculation derived from radiative flux analysis.

Dupont, Jean-Charles; Haeffelin, Martial; Morille, Y.; Comstock, Jennifer M.; Flynn, Connor J.; Long, Charles N.; Sivaraman, Chitra; Newsom, Rob K.

2011-02-16T23:59:59.000Z

382

An Evaluation of WRF Simulations of Clouds over the Southern Ocean with A-Train Observations  

Science Conference Proceedings (OSTI)

The representation of the marine boundary layer (BL) clouds remains a formidable challenge for start-of-the-art simulations. A recent study by Bodas-Salcedo et al. (2012) using the UK Met Office Unified Model highlights that the underprediction of ...

Yi Huang; Steven T. Siems; Michael J. Manton; Gregory Thompson

383

Verification of Cloud Cover Forecast with Satellite Observation over West Africa  

Science Conference Proceedings (OSTI)

The 3-hourly brightness temperatures (BTs) at 10.8 ?m from the Meteosat Second Generation (MSG) satellite were used to document the cloud system variability over West Africa in the summer of 2006 and to evaluate the quality of the Méso-NH model ...

Nathalie Söhne; Jean-Pierre Chaboureau; Françoise Guichard

2008-11-01T23:59:59.000Z

384

profiles of optical Extinction Coefficients Calculated from Droplet Spectra Observed in Marine Stratus Cloud Layers  

Science Conference Proceedings (OSTI)

Airborne measurements of droplet spectra n(r) where r is droplet radius were made in stratus cloud layers over the ocean 130 km southwest of San Diego. Optical extinction coefficients ?e were calculated at selected wavelengths (?= 0.53, 3.75 and ...

V. Ray Noonkester

1985-06-01T23:59:59.000Z

385

The Segregation of Aerosols by Cloud-Nucleating Activity. Part II: Observation of an Urban Aerosol  

Science Conference Proceedings (OSTI)

The submicron aerosol of metropolitan Seattle was segregated into CCN and non-CCN fractions by a high-flux thermal diffusion cloud chamber in series with a dichotomous separator. Each segregated fraction of the five-hour daily sample was ...

Lee Harrison

1985-04-01T23:59:59.000Z

386

Remote Sensing of Cirrus Particle Size Vertical Profile Using...  

NLE Websites -- All DOE Office Websites (Extended Search)

and shapes. The vertical variation of ice crystal size can alter the radiative heatingcooling profiles in cirrus cloudy atmospheres and hence is an important component in the...

387

Probing the Climatological Impact of a Cosmic Ray-Cloud Connection through Low-Frequency Radio Observations  

E-Print Network (OSTI)

It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...

Magee, Nathan

2011-01-01T23:59:59.000Z

388

Comparison of Cloud Fraction and Liquid Water Path between ECMWF simulations and ARM long-term Observations at the NSA Site  

NLE Websites -- All DOE Office Websites (Extended Search)

this poster, seasonal and annual variations of this poster, seasonal and annual variations of cloudiness and liquid water path (LWP) from European Center for Medium-Range Weather Forecasts (ECMWF) model were compared with surface measurement from the ARM Climate Research Facility (ARCF) North Slope of Alaska ( N S A ) s i t e b e t we e n J a n u a r y 1 9 9 9 and December 2004. â—Ź Model simulated large scale features match well with observations. â—Ź There are significant differences in cloud vertical and temporal distributions and in the magnitude. FIG. 1: Time-height display of cloud fraction from model simulations and observations in September 1999. â—Ź Model overestimates high clouds, especially in warm seasons. â—Ź Model makes close estimation for middle clouds. â—Ź Model underestimates low clouds in warm seasons, especially in

389

The 13–14 December 2001 IMPROVE-2 Event. Part II: Comparisons of MM5 Model Simulations of Clouds and Precipitation with Observations  

Science Conference Proceedings (OSTI)

This paper compares airborne in situ observations of cloud microphysical parameters with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) simulations, using the Reisner-2 ...

Matthew F. Garvert; Christopher P. Woods; Brian A. Colle; Clifford F. Mass; Peter V. Hobbs; Mark T. Stoelinga; Justin B. Wolfe

2005-10-01T23:59:59.000Z

390

Surface Solar Radiation Flux and Cloud Radiative Forcing for the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP): A Satellite, Surface Observations, and Radiative Transfer Model Study  

Science Conference Proceedings (OSTI)

This study presents surface solar radiation flux and cloud radiative forcing results obtained by using a combination of satellite and surface observations interpreted by means of a simple plane-parallel radiative transfer model called 2001. This ...

Catherine Gautier; Martin Landsfeld

1997-05-01T23:59:59.000Z

391

Parameterizing Size Distribution in Ice Clouds  

SciTech Connect

PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice cloud optical properties formulated in terms of PSD parameters in combination with remote measurements of thermal radiances to characterize the small mode. This is possible since the absorption efficiency (Qabs) of small mode crystals is larger at 12 µm wavelength relative to 11 µm wavelength due to the process of wave resonance or photon tunneling more active at 12 µm. This makes the 12/11 µm absorption optical depth ratio (or equivalently the 12/11 µm Qabs ratio) a means for detecting the relative concentration of small ice particles in cirrus. Using this principle, this project tested and developed PSD schemes that can help characterize cirrus clouds at each of the three ARM sites: SGP, NSA and TWP. This was the main effort of this project. These PSD schemes and ice sedimentation velocities predicted from them have been used to test the new cirrus microphysics parameterization in the GCM known as the Community Climate Systems Model (CCSM) as part of an ongoing collaboration with NCAR. Regarding the second problem, we developed and did preliminary testing on a passive thermal method for retrieving the total water path (TWP) of Arctic mixed phase clouds where TWPs are often in the range of 20 to 130 g m-2 (difficult for microwave radiometers to accurately measure). We also developed a new radar method for retrieving the cloud ice water content (IWC), which can be vertically integrated to yield the ice water path (IWP). These techniques were combined to determine the IWP and liquid water path (LWP) in Arctic clouds, and hence the fraction of ice and liquid water. We have tested this approach using a case study from the ARM field campaign called M-PACE (Mixed-Phase Arctic Cloud Experiment). This research led to a new satellite remote sensing method that appears promising for detecting low levels of liquid water in high clouds typically between -20 and -36 oC. We hope to develop this method in future research.

DeSlover, Daniel; Mitchell, David L.

2009-09-25T23:59:59.000Z

392

The Diurnal Cycle of the Boundary Layer, Convection, Clouds, and Surface Radiation in a Coastal Monsoon Environment (Darwin Australia)  

SciTech Connect

The diurnal variation of convection and associated cloud and radiative properties remains a significant issue in global NWP and climate models. This study analyzes observed diurnal variability of convection in a coastal monsoonal environment examining the interaction of convective rain clouds, their associated cloud properties, and the impact on the surface radiation and corresponding boundary layer structure during periods where convection is suppressed or active on the large scale. The analysis uses data from the Tropical Warm Pool International Cloud Experiment (TWP-ICE) as well as routine measurements from the Australian Bureau of Meteorology and the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. Both active monsoonal and large-scale suppressed (buildup and break) conditions are examined and demonstrate that the diurnal variation of rainfall is much larger during the break periods and the spatial distribution of rainfall is very different between the monsoon and break regimes. During the active monsoon the total net radiative input to the surface is decreased by more than 3 times the amount than during the break regime - this total radiative cloud forcing is found to be dominated by the shortwave (SW) cloud effects because of the much larger optical thicknesses and persistence of long-lasting anvils and cirrus cloud decks associated with the monsoon regime. These differences in monsoon versus break surface radiative energy contribute to low-level air temperature differences in the boundary layer over the land surfaces.

May, Peter T.; Long, Charles N.; Protat, Alain

2012-08-01T23:59:59.000Z

393

Very Large Array Observations of Ammonia in Infrared-Dark Clouds II: Internal Kinematics  

E-Print Network (OSTI)

Infrared-dark clouds (IRDCs) are believed to be the birthplaces of rich clusters and thus contain the earliest phases of high-mass star formation. We use the Green Bank Telescope (GBT) and Very Large Array (VLA) maps of ammonia (NH3) in six IRDCs to measure their column density and temperature structure (Paper 1), and here, we investigate the kinematic structure and energy content. We find that IRDCs overall display organized velocity fields, with only localized disruptions due to embedded star formation. The local effects seen in NH3 emission are not high velocity outflows but rather moderate (few km/s) increases in the line width that exhibit maxima near or coincident with the mid-infrared emission tracing protostars. These line width enhancements could be the result of infall or (hidden in NH3 emission) outflow. Not only is the kinetic energy content insufficient to support the IRDCs against collapse, but also the spatial energy distribution is inconsistent with a scenario of turbulent cloud support. We co...

Ragan, Sarah E; Bergin, Edwin A; Wilner, David

2012-01-01T23:59:59.000Z

394

SUBMILLIMETER OBSERVATIONS OF DENSE CLUMPS IN THE INFRARED DARK CLOUD G049.40-00.01  

Science Conference Proceedings (OSTI)

We obtained 350 and 850 {mu}m continuum maps of the infrared dark cloud G049.40-00.01. Twenty-one dense clumps were identified within G049.40-00.01 based on the 350 {mu}m continuum map with an angular resolution of about 9.''6. We present submillimeter continuum maps and report physical properties of the clumps. The masses of clumps range from 50 to 600 M{sub Sun }. About 70% of the clumps are associated with bright 24 {mu}m emission sources, and they may contain protostars. The two most massive clumps show extended, enhanced 4.5 {mu}m emission indicating vigorous star-forming activity. The clump-size-mass distribution suggests that many of them are forming high-mass stars. G049.40-00.01 contains numerous objects in various evolutionary stages of star formation, from pre-protostellar clumps to H II regions.

Kang, Miju; Choi, Minho [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Bieging, John H. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Rho, Jeonghee [SOFIA Science Center, USRA/NASA Ames Research Center, Moffet Field, CA 94035 (United States); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of); Tsai, Chao-Wei, E-mail: mjkang@kasi.re.kr [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2011-12-20T23:59:59.000Z

395

Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity to Microphysics Parameterizations  

Science Conference Proceedings (OSTI)

Single-layer mixed-phase stratiform (MPS) Arctic clouds, which formed under conditions of large surface heat flux combined with general subsidence during a subperiod of the Atmospheric Radiation Measurement (ARM) Program’s Mixed-Phase Arctic ...

Yali Luo; Kuan-Man Xu; Hugh Morrison; Greg McFarquhar

2008-04-01T23:59:59.000Z

396

Application of Feature Calibration and Alignment to High-resolution Analysis: Examples Using Observations Sensitive to Cloud and Water Vapor  

Science Conference Proceedings (OSTI)

Alignment errors, i.e. cases where coherent structures (“features”) of clouds or precipitation in the background have position errors, can lead to large and non-Gaussian background errors. Assimilation of cloud-affected radiances using additive ...

Thomas Nehrkorn; Bryan Woods; Thomas Auligné; Ross N. Hoffman

397

Initialization of a Cloud-Resolving Model with Airborne Doppler Radar Observations of an Oceanic Tropical Convective System  

Science Conference Proceedings (OSTI)

Doppler radar–derived fields of wind and reflectivity, retrieved temperature perturbations, estimated water vapor, and cloud water contents are used to initialize a nonhydrostatic cloud-resolving model. Airborne Doppler data collected in a ...

Soline Bielli; Frank Roux

1999-06-01T23:59:59.000Z

398

Study of ice cloud properties using infrared spectral data  

E-Print Network (OSTI)

The research presented in this thesis involves the study of ice cloud microphysical and optical properties using both hyperspectral and narrowband infrared spectral data. First, ice cloud models are developed for the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the METOP-A satellite, which provide the bulk-scattering properties of these clouds for the 8461 IASI channels between 645 and 2760 cm-1. We investigate the sensitivity of simulated brightness temperatures in this spectral region to the bulk-scattering properties of ice clouds containing individual ice crystal habits as well as for one habit distribution. The second part of this thesis describes an algorithm developed to analyze the sensitivity of simulated brightness temperatures at 8.5 and 11.0 µm to changes in effective cloud temperature by adjusting cloud top height and geometric thickness in a standard tropical atmosphere. Applicability of using these channels in a bi-spectral approach to retrieve cirrus cloud effective particle size and optical thickness is assessed. Finally, the algorithm is applied to the retrieval of these ice cloud properties for a case of single-layered cirrus cloud over a tropical ocean surface using measurements from the Moderate Resolution Infrared Spectroradiometer (MODIS). Cloud top height and geometric thickness in the profile are adjusted to assess the influence of effective cloud temperature on the retrieval.

Garrett, Kevin James

2007-08-01T23:59:59.000Z

399

Indirect and Semi-Direct Aerosol Campaign: The Impact of Arctic Aerosols on Clouds  

SciTech Connect

A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the arctic boundary layer in the vicinity of Barrow, Alaska was collected in April 2008 during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) sponsored by the Department of Energy Atmospheric Radiation Measurement (ARM) and Atmospheric Science Programs. The primary aim of ISDAC was to examine indirect effects of aerosols on clouds that contain both liquid and ice water. The experiment utilized the ARM permanent observational facilities at the North Slope of Alaska (NSA) in Barrow. These include a cloud radar, a polarized micropulse lidar, and an atmospheric emitted radiance interferometer as well as instruments specially deployed for ISDAC measuring aerosol, ice fog, precipitation and spectral shortwave radiation. The National Research Council of Canada Convair-580 flew 27 sorties during ISDAC, collecting data using an unprecedented 42 cloud and aerosol instruments for more than 100 hours on 12 different days. Data were obtained above, below and within single-layer stratus on 8 April and 26 April 2008. These data enable a process-oriented understanding of how aerosols affect the microphysical and radiative properties of arctic clouds influenced by different surface conditions. Observations acquired on a heavily polluted day, 19 April 2008, are enhancing this understanding. Data acquired in cirrus on transit flights between Fairbanks and Barrow are improving our understanding of the performance of cloud probes in ice. Ultimately the ISDAC data will be used to improve the representation of cloud and aerosol processes in models covering a variety of spatial and temporal scales, and to determine the extent to which long-term surface-based measurements can provide retrievals of aerosols, clouds, precipitation and radiative heating in the Arctic.

McFarquhar, Greg; Ghan, Steven J.; Verlinde, J.; Korolev, Alexei; Strapp, J. Walter; Schmid, Beat; Tomlinson, Jason M.; Wolde, Mengistu; Brooks, Sarah D.; Cziczo, Daniel J.; Dubey, Manvendra K.; Fan, Jiwen; Flynn, Connor J.; Gultepe, Ismail; Hubbe, John M.; Gilles, Mary K.; Laskin, Alexander; Lawson, Paul; Leaitch, W. R.; Liu, Peter S.; Liu, Xiaohong; Lubin, Dan; Mazzoleni, Claudio; Macdonald, A. M.; Moffet, Ryan C.; Morrison, H.; Ovchinnikov, Mikhail; Shupe, Matthew D.; Turner, David D.; Xie, Shaocheng; Zelenyuk, Alla; Bae, Kenny; Freer, Matthew; Glen, Andrew

2011-02-01T23:59:59.000Z

400

A Parametric Radiative Forcing Model for Contrail Cirrus  

Science Conference Proceedings (OSTI)

A new parameterized analytical model is presented to compute the instantaneous radiative forcing (RF) at the top of the atmosphere (TOA) produced by an additional thin contrail cirrus layer (called “contrail” below). The model calculates the RF ...

U. Schumann; B. Mayer; K. Graf; H. Mannstein

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Observed Increase of TTL Temperature and Water Vapor in Polluted Clouds over Asia  

Science Conference Proceedings (OSTI)

Satellite observations are analyzed to examine the correlations between aerosols and the tropical tropopause layer (TTL) temperature and water vapor. This study focuses on two regions, both of which are important pathways for the mass transport ...

Hui Su; Jonathan H. Jiang; Xiaohong Liu; Joyce E. Penner; William G. Read; Steven Massie; Mark R. Schoeberl; Peter Colarco; Nathaniel J. Livesey; Michelle L. Santee

2011-06-01T23:59:59.000Z

402

A Cloud and Precipitation Feature Database from Nine Years of TRMM Observations  

Science Conference Proceedings (OSTI)

An event-based method of analyzing the measurements from multiple satellite sensors is presented by using observations of the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR), Microwave Imager (TMI), Visible and Infrared ...

Chuntao Liu; Edward J. Zipser; Daniel J. Cecil; Stephen W. Nesbitt; Steven Sherwood

2008-10-01T23:59:59.000Z

403

Studying Clouds and Aerosols with Lidar Depolarization Ratio and Backscatter Relationships  

E-Print Network (OSTI)

This dissertation consists of three parts, each devoted to a particular issue of significant importance for CALIPSO lidar observation of depolarization ratio (delta) and backscatter (gamma?) to improve current understanding of the microphysical properties of clouds and aerosols. The relationships between depolarization ratio and backscatter allow us to retrieve particle thermodynamic phase and shape and/or orientation of aerosols and clouds. The first part is devoted to the investigation of the relationships between lidar backscatter and the corresponding depolarization ratio for different cloud classifications and aerosol types. For each cloud and aerosol types, layer-averaged backscatter and backscattering depolarization ratio from the CALIPSO measurements are discussed. The present results demonstrate the unique capabilities of the CALIPSO lidar instrument for determining cloud phase and aerosols subtypes. In the second part, we evaluate the MODIS IR cloud phase with the CALIPSO cloud products. The three possible misclassifications of MODIS IR cloud phasealgorithm, which are studied by Nasiri and Kahn (2008) with radiative transfer modeling, are tested by comparing between MODIS IR phase and CALIOP observations. The current results support their hypotheses, which is that the MODIS phase algorithm may tend to classify thin cirrus clouds as water clouds or mixed phase clouds or unknown, and classify midlevel and/or mid-temperature clouds as mixed or unknown phase. In the third part, we present a comparison of mineral dust aerosol retrievals from two instruments, MODIS and CALIPSO lidar. And, we implement and evaluate a new mineral dust detection algorithm based on the analysis of thin dust radiative signature. In comparison, three commonly used visible and IR mineral dust detection algorithms, including BTD procedure, D parameter method, and multi-channel image algorithm, are evaluated with CALIPSO aerosol classification. The comparison reveals that those dust detection algorithms are not effective for optically thin dust layers, but for thick dust storm. The new algorithm using discriminant analysis with CALIPSO observation is much better in detecting thin dust layer of optical thickness between 0.1 and 2.

Cho, Hyoun-Myoung

2011-12-01T23:59:59.000Z

404

Possible Observations of Noctilucent Clouds by Thomas Romney Robinson C. J. Butler  

E-Print Network (OSTI)

.They are believed to be composed of ice crystals which reflect the light of the Sun shining from below the observer to be composed of extra-terrestrial particles which, as they descend through the atmosphere to the vicinity Observatory, best known by meteorologists for his Cup Anemometer. From a painting by Maud Humphrey

405

Simulation of microphysical structure associated with tropical cloud clusters using mesoscale model and comparison with TRMM observations  

Science Conference Proceedings (OSTI)

An attempt has been made in the present study to examine the microphysical structure of a non-squall Tropical Cloud Cluster (TCC). Three-dimensional model simulations of cloud microphysical structure associated with a non-squall TCC occurred on 26 October ...

S. Abhilash; K. Mohankumar; S. Das

2008-04-01T23:59:59.000Z

406

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

E-Print Network (OSTI)

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

Solomon, Amy

407

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

Science Conference Proceedings (OSTI)

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

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

2010-04-01T23:59:59.000Z

408

Temporal and Vertical Distribution of Acidity and Ionic Composition in Clouds: Comparison between Modeling Results and Observations  

Science Conference Proceedings (OSTI)

Cyclic temporal variations of pH and ionic concentration in sampled clouds which traversed the Mt. Mitchell State Park site (35°44?05?N, 82°17?15?W, 2006 m MSL) during the summers of 1986, 1987 and 1988 are reported. These clouds typically had a ...

T. P. DeFelice; V. K. Saxena

1990-05-01T23:59:59.000Z

409

Spitzer Infrared Spectrograph Observations of Magellanic Cloud Planetary Nebulae: the nature of dust in low metallicity circumstellar ejecta  

E-Print Network (OSTI)

We present 5 - 40 micron spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The spectra show the presence of a combination of nebular emission lines and solid-state features from dust, superimposed on the thermal IR continuum. By analyzing the 25 LMC and 16 SMC PNe in our sample we found that the IR spectra of 14 LMC and 4 SMC PNe are dominated by nebular emission lines, while the other spectra show solid-state features. We observed that the solid-state features are compatible with carbon-rich dust grains (SiC, polycyclic aromatic hydrocarbons (PAHs), etc.) in most cases, except in three PNe showing oxygen-rich dust features. The frequency of carbonaceous dust features is generally higher in LMC than in SMC PNe. The spectral analysis allowed the correlations of the dust characteristics with the gas composition and morphology, and the properties of the central stars. We found that: 1) all PNe with carbonaceous dust features have C/O>1, none of these being bipolar or otherwise highly asymmetric; 2) all PNe with oxygen-rich dust features have C/Oproduction efficiency depends on metallicity, with low metallicity environments not favoring dust production.

L. Stanghellini; P. Garcia-Lario; D. A. Garcia-Hernandez; J. V. Perea-Calderon; J. E. Davies; A. Manchado; E. Villaver; R. A. Shaw

2007-09-04T23:59:59.000Z

410

Determination of the Optical Thickness and Effective Particle Radius of Clouds from Reflected Solar Radiation Measurements. Part II: Marine Stratocumulus Observations  

Science Conference Proceedings (OSTI)

A multispectral scanning radiometer has been used to obtain measurements of the reflection function of marine stratocumulus clouds at 0.75, 1.65 and 2.16 ?m. These observations were obtained from the NASA ER-2 aircraft as part of the First ISCCP [...

Teruyuki Nakajima; Michael D. King; James D. Spinhirne; Lawrence F. Radke

1991-03-01T23:59:59.000Z

411

The Retrieval of Marine Stratiform Cloud Properties from Multiple Observations in the 3.9-µm Window under Conditions of Varying Solar Illumination  

Science Conference Proceedings (OSTI)

Radiometric observations in the 3.9-µm region have been used by a number of investigators for the determination of cloud parameters or sea surface temperature at night. Only a few attempts have been made to perform quantitative assessments of ...

Thomas J. Kleespies

1995-07-01T23:59:59.000Z

412

Radiative Transfer Simulations Using Mesoscale Cloud Model Outputs: Comparisons with Passive Microwave and Infrared Satellite Observations for Midlatitudes  

Science Conference Proceedings (OSTI)

Real midlatitude meteorological cases are simulated over western Europe with the cloud mesoscale model Méso-NH, and the outputs are used to calculate brightness temperatures at microwave frequencies with the Atmospheric Transmission at Microwave (...

Ingo Meirold-Mautner; Catherine Prigent; Eric Defer; Juan R. Pardo; Jean-Pierre Chaboureau; Jean-Pierre Pinty; Mario Mech; Susanne Crewell

2007-05-01T23:59:59.000Z

413

Understanding the Importance of Microphysics and Macrophysics for Warm Rain in Marine Low Clouds. Part I: Satellite Observations  

Science Conference Proceedings (OSTI)

The importance of macrophysical variables [cloud thickness, liquid water path (LWP)] and microphysical variables (effective radius re, effective droplet concentration Neff) on warm drizzle intensity and frequency across the tropics and subtropics ...

Terence L. Kubar; Dennis L. Hartmann; Robert Wood

2009-10-01T23:59:59.000Z

414

Comparison of Four Cloud Schemes in Simulating the Seasonal Mean Field Forced by the Observed Sea Surface Temperature  

Science Conference Proceedings (OSTI)

The impacts of four stratiform cloud parameterizations on seasonal mean fields are investigated using the global version of the Experimental Climate Prediction Center (ECPC) global-to-regional forecast system (G-RSM). The simulated fields are ...

Akihiko Shimpo; Masao Kanamitsu; Sam F. Iacobellis; Song-You Hong

2008-07-01T23:59:59.000Z

415

Evaluating Cloud Contamination in Clear-Sky MODIS Terra Daytime Land Surface Temperatures Using Ground-Based Meteorology Station Observations  

Science Conference Proceedings (OSTI)

Environment Canada meteorological station hourly sampled air temperatures Tair at four stations in the southwest Yukon were used to identify cloud contamination in the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra clear-sky daytime ...

Scott N. Williamson; David S. Hik; John A. Gamon; Jeffrey L. Kavanaugh; Saewan Koh

2013-03-01T23:59:59.000Z

416

A Study of the Aerosol Effect on a Cloud Field with Simultaneous Use of GCM Modeling and Satellite Observation  

Science Conference Proceedings (OSTI)

The indirect effect of aerosols was simulated by a GCM for nonconvective water clouds and was compared with remote sensing results from the Advanced Very High Resolution Radiometer (AVHRR) satellite-borne sensor for January, April, July, and ...

Kentaroh Suzuki; Teruyuki Nakajima; Atusi Numaguti; Toshihiko Takemura; Kazuaki Kawamoto; Akiko Higurashi

2004-01-01T23:59:59.000Z

417

Marine Stratocumulus Cloud Fields off the Coast of Southern California Observed Using LANDSAT Imagery. Part I: Structural Characteristics  

Science Conference Proceedings (OSTI)

The structural characteristics of stratocumulus cloud fields off the coast of southern California are investigated using LANDSAT Multispectral Scanner (MSS) imagery. Twelve scenes in this area are examined along with three other stratocumulus ...

R. M. Welch; K. S. Kuo; B. A. Wielicki; S. K. Sengupta; L. Parker

1988-04-01T23:59:59.000Z

418

The Retrieval of Profiles of Particulate Extinction from Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) Data: Algorithm Description  

Science Conference Proceedings (OSTI)

This work describes the algorithms used for the fully automated retrieval of profiles of particulate extinction coefficients from the attenuated backscatter data acquired by the lidar on board the Cloud-Aerosol Lidar Infrared Pathfinder Satellite ...

Stuart A. Young; Mark A. Vaughan

2009-06-01T23:59:59.000Z

419

GREEN BANK TELESCOPE OBSERVATIONS OF THE NH{sub 3} (3, 3) AND (6, 6) TRANSITIONS TOWARD SAGITTARIUS A MOLECULAR CLOUDS  

SciTech Connect

Ammonia (3, 3) and (6, 6) transitions have been observed using the Green Bank Telescope toward the Sgr A region. The gas is mainly concentrated in 50 km s{sup -1} and 20 km s{sup -1} clouds located in a plane inclined to the galactic plane. These 'main' clouds appear to be virialized and influenced by the expansion of the supernova remnant Sgr A East. The observed emission shows very complicated features in the morphology and velocity structure. Gaussian multi-component fittings of the observed spectra revealed that various 'streaming' gas components exist all over the observed region. These components include those previously known as 'streamers' and 'ridges', but most of these components appear not to be directly connected to the major gas condensations (the 50 km s{sup -1} and 20 km s{sup -1} clouds). They are apparently located out of the galactic plane, and they may have a different origin than the major gas condensations. Some of the streaming components are expected to be sources that feed the circumnuclear disk of our Galactic center directly and episodically. They may also evolve differently than major gas condensations under the influence of the activities of the Galactic center.

Minh, Young Chol [Korea Astronomy and Space Science Institute, Daeduk-daero 776, Yuseong, Daejeon 305-348 (Korea, Republic of); Liu, Hauyu Baobab; Ho, Paul T. P.; Hsieh, Pei-Ying; Su, Yu-Nung [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Kim, Sungsoo S. [Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyungki-do 446-701 (Korea, Republic of); Wright, Melvyn [Radio Astronomy Laboratory, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States)

2013-08-10T23:59:59.000Z

420

Assessing the Radiative Impact of Clouds of Low Optical Depth  

NLE Websites -- All DOE Office Websites (Extended Search)

the Radiative Impact of Clouds of the Radiative Impact of Clouds of Low Optical Depth W. O'Hirok and P. Ricchiazzi Institute for Computational Earth System Science University of California Santa Barbara, California C. Gautier Department of Geography and Institute for Computational Earth System Science University of California Santa Barbara, California Introduction Analysis from the International Satellite Cloud Climatology Project (ISCCP) reveals that the global mean cloud optical depth is surprisingly low (i.e., Ď„ = 3.8). While this value is probably dominated by extensive fields of cirrus, the average for liquid water clouds is also likely smaller than expected. It is in this regime (Ď„ <10) where remote measurements of cloud optical thickness or liquid water path (LWP)

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Turbulent molecular clouds  

E-Print Network (OSTI)

Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds trying to confront the two approaches wherever possible. After a broad presentation of the cold interstellar medium and molecular clouds, we emphasize the dynamical processes with special focus to turbulence and its impact on cloud evolution. We then review our knowledge of the velocity, density and magnetic fields. We end by openings towards new chemistry models and the links between molecular cloud structure and star--formation rates.

Hennebelle, Patrick

2012-01-01T23:59:59.000Z

422

IC cloud: Enabling compositional cloud  

Science Conference Proceedings (OSTI)

Cloud computing has attracted great interest from both academic and industrial communities. Different paradigms, architectures and applications based on the concept of cloud have emerged. Although many of them have been quite successful, efforts are ... Keywords: Cloud computing, cloud elasticity, cloud service, compositional cloud, infrastructure as a service (IaaS)

Yi-Ke Guo; Li Guo

2011-08-01T23:59:59.000Z

423

Effective Radius of Ice Particles in Cirrus and Contrails  

Science Conference Proceedings (OSTI)

This paper discusses the ratio C between the volume mean radius and the effective radius of ice particles in cirrus and contrails. The volume mean radius is proportional to the third root of the ratio between ice water content and number of ice ...

U. Schumann; B. Mayer; K. Gierens; S. Unterstrasser; P. Jessberger; A. Petzold; C. Voigt; J-F. Gayet

2011-02-01T23:59:59.000Z

424

Observations of the Cross-Lake Cloud and Snow Evolution in a Lake-Effect Snow Event  

Science Conference Proceedings (OSTI)

While the total snowfall produced in lake-effect storms can be considerable, little is known about how clouds and snow evolve within lake-effect boundary layers. Data collected over Lake Michigan on 10 January 1998 during the Lake-Induced ...

Faye E. Barthold; David A. R. Kristovich

2011-08-01T23:59:59.000Z

425

Classification of Ice Crystal Shapes in Midlatitude Ice Clouds from Three Years of Lidar Observations over the SIRTA Observatory  

Science Conference Proceedings (OSTI)

This paper presents a study of ice crystal shapes in midlatitude ice clouds inferred from a technique based on the comparison of ray-tracing simulations with lidar depolarization ratio measured at 532 nm. This technique is applied to three years ...

Vincent Noel; Helene Chepfer; Martial Haeffelin; Yohann Morille

2006-11-01T23:59:59.000Z

426

Observations of Quasi-Stationary and Shallow Orographic Snow Clouds: Spatial Distributions of Supercooled Liquid Water and Snow Particles  

Science Conference Proceedings (OSTI)

On 25 February 1999, due to a winter monsoon after a cyclonic storm, orographic snow clouds formed under conditions of weak cold advection on the western side of the central mountain range of Japan. In this study, the Ka-band Doppler radar and ...

Kenichi Kusunoki; Masataka Murakami; Narihiro Orikasa; Mizuho Hoshimoto; Yoshinobu Tanaka; Yoshinori Yamada; Hakaru Mizuno; Kyosuke Hamazu; Hideyuki Watanabe

2005-04-01T23:59:59.000Z

427

Polarimetric Radar Observations in the Ice Region of Precipitating Clouds at C-Band and X-Band Radar Frequencies  

Science Conference Proceedings (OSTI)

Data collected by C-band and X-band radars in northwestern Italy are analyzed to study the behavior of the polarimetric variables in the ice region of precipitating clouds, with special emphasis on the specific differential phase Kdp. It is found ...

R. Bechini; L. Baldini; V. Chandrasekar

2013-05-01T23:59:59.000Z

428

Polar Stratospheric Cloud Observations in the 2006/07 Arctic Winter by Using an Improved Micropulse Lidar  

Science Conference Proceedings (OSTI)

The potential of a new improved version of micropulse lidar (MPL-4) on polar stratospheric cloud (PSC) detection is evaluated in the Arctic over Ny-Ĺlesund (79°N, 12°E), Norway. The campaign took place from January to February 2007 in the frame ...

Carmen Cordoba-Jabonero; Manuel Gil; Margarita Yela; Marion Maturilli; Roland Neuber

2009-10-01T23:59:59.000Z

429

Assessment of Uncertainty in Cloud Radiative Effects and Heating Rates through Retrieval Algorithm Differences: Analysis using 3-years of ARM data at Darwin, Australia  

SciTech Connect

Ground-based radar and lidar observations obtained at the Department of Energy’s Atmospheric Radiation Measurement Program’s Tropical Western Pacific site located in Darwin, Australia are used to retrieve ice cloud properties in anvil and cirrus clouds. Cloud microphysical properties derived from four different retrieval algorithms (two radar-lidar and two radar only algorithms) are compared by examining mean profiles and probability density functions of effective radius (Re), ice water content (IWC), extinction, ice number concentration, ice crystal fall speed, and vertical air velocity. Retrieval algorithm uncertainty is quantified using radiative flux closure exercises. The effect of uncertainty in retrieved quantities on the cloud radiative effect and radiative heating rates are presented. Our analysis shows that IWC compares well among algorithms, but Re shows significant discrepancies, which is attributed primarily to assumptions of particle shape. Uncertainty in Re and IWC translates into sometimes-large differences in cloud radiative effect (CRE) though the majority of cases have a CRE difference of roughly 10 W m-2 on average. These differences, which we believe are primarily driven by the uncertainty in Re, can cause up to 2 K/day difference in the radiative heating rates between algorithms.

Comstock, Jennifer M.; Protat, Alain; McFarlane, Sally A.; Delanoe, Julien; Deng, Min

2013-05-22T23:59:59.000Z

430

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

SciTech Connect

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

Michael R. Poellot

2009-01-09T23:59:59.000Z

431

Reply to Comments on ``Seasonal Variation of the Physical Properties of Marine Boundary Layer Clouds off the California Coast''  

E-Print Network (OSTI)

CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Stellite Observations (CALIPSO). J. Geophys

432

CALIPSO/CALIOP Cloud Phase Discrimination Algorithm  

Science Conference Proceedings (OSTI)

The current cloud thermodynamic phase discrimination by Cloud-Aerosol Lidar Pathfinder Satellite Observations (CALIPSO) is based on the depolarization of backscattered light measured by its lidar [Cloud-Aerosol Lidar with Orthogonal Polarization (...

Yongxiang Hu; David Winker; Mark Vaughan; Bing Lin; Ali Omar; Charles Trepte; David Flittner; Ping Yang; Shaima L. Nasiri; Bryan Baum; Robert Holz; Wenbo Sun; Zhaoyan Liu; Zhien Wang; Stuart Young; Knut Stamnes; Jianping Huang; Ralph Kuehn

2009-11-01T23:59:59.000Z

433

Observations of tornadoes and wall clouds with a portable FM-CW Doppler radar: 1989--1990 results  

SciTech Connect

The purpose of this paper is to report on our progress using a portable, 1 W,FM (frequency modulated)-CW (continuous wave) Doppler radar developed at the Los Alamos National Laboratory (LANL), to make measurements of the wind field in tornadoes and wall clouds along with simultaneous visual documentation. Results using a CW version of the radar in 1987--1988 are given in Bluestein and Unruh (1989). 18 refs., 2 figs., 1 tab.

Bluestein, H.B. (Oklahoma Univ., Norman, OK (USA). School of Meteorology); Unruh, W.P. (Los Alamos National Lab., NM (USA))

1990-01-01T23:59:59.000Z

434

A Critical Review of the Australian Experience in Cloud Seeding  

Science Conference Proceedings (OSTI)

From 1947 to 1994 a number of cloud-seeding experiments were done in Australia based on the static cloud-seeding hypothesis. A critical analysis of these successive cloud-seeding experiments, coupled with microphysical observations of the clouds, ...

Brian F. Ryan; Warren D. King

1997-02-01T23:59:59.000Z

435

Evaluation of AIRS cloud thermodynamic phase determination with CALIPSO  

Science Conference Proceedings (OSTI)

The Atmospheric Infrared Sounder (AIRS) infrared-based cloud thermodynamic phase retrievals are evaluated using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) cloud thermodynamic phase. The AIRS cloud phase is ...

Hongchun Jin; Shaima L. Nasiri

436

On the Use of Cloud Forcing to Estimate Cloud Feedback  

Science Conference Proceedings (OSTI)

Uncertainty in cloud feedback is the leading cause of discrepancy in model predictions of climate change. The use of observed or model-simulated radiative fluxes to diagnose the effect of clouds on climate sensitivity requires an accurate ...

Brian J. Soden; Anthony J. Broccoli; Richard S. Hemler

2004-10-01T23:59:59.000Z

437

FORMATION OF MASSIVE MOLECULAR CLOUD CORES BY CLOUD-CLOUD COLLISION  

SciTech Connect

Recent observations of molecular clouds around rich massive star clusters including NGC 3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by cloud-cloud collision. We find that the massive molecular cloud cores have large effective Jeans mass owing to the enhancement of the magnetic field strength by shock compression and turbulence in the compressed layer. Our results predict that massive molecular cloud cores formed by the cloud-cloud collision are filamentary and threaded by magnetic fields perpendicular to the filament.

Inoue, Tsuyoshi [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa 252-5258 (Japan); Fukui, Yasuo, E-mail: inouety@phys.aoyama.ac.jp [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

2013-09-10T23:59:59.000Z

438

Supersaturation Intermittency in Turbulent Clouds  

Science Conference Proceedings (OSTI)

It is hypothesized that bursts of high supersaturation are produced in turbulent, convective clouds through interactions between cloud droplets and the small-scale structure of atmospheric turbulence. This hypothesis is based on the observation ...

Raymond A. Shaw

2000-10-01T23:59:59.000Z

439

The Experimental Cloud Lidar Pilot Study (ECLIPS) for Cloud—Radiation Research  

Science Conference Proceedings (OSTI)

The Experimental Cloud Lidar Pilot Study (ECLIPS) was initiated to obtain statistics on cloud-base height, extinction, optical depth, cloud brokenness, and surface fluxes. Two observational phases have taken place, in October-December 1989 and ...

C. M. Platt; S. A. Young; A. I. Carswell; S. R. Pal; M. P. McCormick; D. M. Winker; M. DelGuasta; L. Stefanutti; W. L. Eberhard; M. Hardesty; P. H. Flamant; R. Valentin; B. Forgan; G. G. Gimmestad; H. Jäger; S. S. Khmelevtsov; I. Kolev; B. Kaprieolev; Da-ren Lu; K. Sassen; V. S. Shamanaev; O. Uchino; Y. Mizuno; U. Wandinger; C. Weitkamp; A. Ansmann; C. Wooldridge

1994-09-01T23:59:59.000Z

440

Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization Schemes in Convection-Permitting Ensemble Forecasts using Synthetic GOES-13 Satellite Observations  

Science Conference Proceedings (OSTI)

In this study, the ability of several cloud microphysical and planetary boundary layer parameterization schemes to accurately simulate cloud characteristics within 4-km-grid-spacing ensemble forecasts over the contiguous U.S. was evaluated through ...

Rebecca Cintineo; Jason A. Otkin; Ming Xue; Fanyou Kong

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Retrieval of Thermal and Microphysical Variables in Observed Convective Storms. Part II: Sensitivity of Cloud Processes to Variation of the Microphysical Parameterization  

Science Conference Proceedings (OSTI)

The hydrometeor content and thermal fields in a thunderstorm are estimated from a three-dimensional kinematic cloud model employing Doppler wind fields and parameterized microphysical processes. The sensitivity of the cloud model calculations to ...

Conrad L. Ziegler

1988-03-01T23:59:59.000Z

442

Evaluation of Model-Predicted Top-of-Atmosphere Radiation and Cloud Parameters over Africa with Observations from GERB and SEVIRI  

Science Conference Proceedings (OSTI)

This study compared the Regional Atmospheric Climate Model version 2 (RACMO) with satellite data by simultaneously looking at cloud properties and top-of-atmosphere (TOA) fluxes. This study used cloud properties retrieved from Spinning Enhanced ...

Wouter Greuell; Erik van Meijgaard; Nicolas Clerbaux; Jan Fokke Meirink

2011-08-01T23:59:59.000Z

443

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

SciTech Connect

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

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

2005-03-18T23:59:59.000Z

444

Multiview Cloud-Top Height and Wind Retrieval with Photogrammetric Methods: Application to Meteosat-8 HRV Observations  

Science Conference Proceedings (OSTI)

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) currently operates three geostationary satellites: Meteosat-5, Meteosat-7, and Meteosat-8. Observations by Meteosat-5 can be combined with observations from ...

Gabriela Seiz; Stephen Tjemkes; Philip Watts

2007-08-01T23:59:59.000Z

445

CDIAC Cloud Data Sets  

NLE Websites -- All DOE Office Websites (Extended Search)

Period of Record A Gridded Climatology of Clouds over Land (1971-1996) and Ocean (1954-2008) from Surface Observations Worldwide (CDIAC NDP-026E) C.J. Hahn and S.G. Warren...

446

Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

This paper reviews the current knowledge of the climatological, structural, and organizational aspects of stratocumulus clouds and the physical processes controlling them. More of Earth’s surface is covered by stratocumulus clouds than by any ...

Robert Wood

2012-08-01T23:59:59.000Z

447

Evaluating and Constraining Ice Cloud Parameterizations in CAM5 using Aircraft Measurements from the SPARTICUS Campaign  

Science Conference Proceedings (OSTI)

This study uses aircraft measurements of relative humidity and ice crystal size distribution collected in synoptic cirrus during the SPARTICUS (Small PARTicles In CirrUS) field campaign to evaluate and constrain ice cloud parameterizations in the Community Atmosphere Model version 5. The probability density function (PDF) of ice crystal number concentration (Ni) derived from high frequency (1 Hz) measurements features a strong dependence on ambient temperature. As temperature decreases from -35°C to -62°C, the peak in the PDF shifts from 10-20 L-1 to 200-1000 L-1, while the ice crystal number concentration shows a factor of 6-7 increase. Model simulations are performed with two different insitu ice nucleation schemes. One of the schemes can reproduce a clear increase of Ni with decreasing temperature, by using either an observation based ice nuclei spectrum or a classical theory based spectrum with a relatively low (5%-10%) maximum freezing ratio for dust aerosols. The simulation with the other scheme, which assumes a high maximum freezing ratio (100%), shows much weaker temperature dependence of Ni. Simulations are also performed to test empirical parameters related to water vapor deposition and the auto-conversion of ice crystals to snow. Results show that a value between 0.05 and 0.1 for the water vapor deposition coefficient and 250 um for the critical ice crystal size can produce good agreements between model simulation and the SPARTICUS measurements in terms of ice crystal number concentration and effective radius. The climate impact of perturbing these parameters is also discussed.

Zhang, Kai; Liu, Xiaohong; Wang, Minghuai; Comstock, Jennifer M.; Mitchell, David; Mishra, Subhashree; Mace, Gerald G.

2013-05-14T23:59:59.000Z

448

Simultaneous Occurrence of Different Cloud Types  

Science Conference Proceedings (OSTI)

Cloud observations from land stations and from ships in the ocean are used to investigate the frequency of observation and the co-occurrence of different cloud types, and the geographical and seasonal variations of these co-occurrences. Ground-...

Stephen G. Warren; Carole J. Hahn; Julius London

1985-07-01T23:59:59.000Z

449

Evaluation and Intercomparison of Cloud Fraction and Radiative Fluxes in Recent Reanalyses over the Arctic Using BSRN Surface Observations  

Science Conference Proceedings (OSTI)

With continual advancements in data assimilation systems, new observing systems, and improvements in model parameterizations, several new atmospheric reanalysis datasets have recently become available. Before using these new reanalyses it is ...

Behnjamin J. Zib; Xiquan Dong; Baike Xi; Aaron Kennedy

2012-04-01T23:59:59.000Z

450

Assimilation of Satellite Imager Data and Surface Observations to Improve Analysis of Circulations Forced by Cloud Shading Contrasts  

Science Conference Proceedings (OSTI)

An assimilation system that performs continuous assimilation of satellite imager data and intermittent assimilation of hourly surface observations is described. The system was applied to a case study of the southeast United States that was ...

Frank H. Ruggiero; George D. Modica; Alan E. Lipton

2000-02-01T23:59:59.000Z

451

Validating the Validation: The Influence of Liquid Water Distribution in Clouds on the Intercomparison of Satellite and Surface Observations  

Science Conference Proceedings (OSTI)

The intercomparison of LWP retrievals from observations by a geostationary satellite imager [Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat Second Generation (MSG)] and a ground-based microwave (MW) radiometer is ...

N. A. J. Schutgens; R. A. Roebeling

2009-08-01T23:59:59.000Z

452

Climatology of Surface Meteorology, Surface Fluxes, Cloud Fraction, and Radiative Forcing over the Southeast Pacific from Buoy Observations  

Science Conference Proceedings (OSTI)

A 5-yr climatology of the meteorology, including boundary layer cloudiness, for the southeast Pacific region is presented using observations from a buoy located at 20°S, 85°W. The sea surface temperature and surface air temperature exhibit a ...

Virendra P. Ghate; Bruce A. Albrecht; Christopher W. Fairall; Robert A. Weller

2009-10-01T23:59:59.000Z

453

A Parameterization of the Particle Size Spectrum of Ice Clouds in Terms of the Ambient Temperature and the Ice Water Content  

Science Conference Proceedings (OSTI)

A data set obtained in cirrus clouds has been examined to deduce any dependencies of the particle size spectral form or the crystal habit on the temperature. It was found that both form of the spectra and crystal habit changed systematically with ...

Andrew J. Heymsfield; C. M. R. Platt

1984-03-01T23:59:59.000Z

454

Cloud-Cover Distributions and Correlations  

Science Conference Proceedings (OSTI)

Observations of cloud cover (in oktas or tenths) by ground-based observers have been studied to investigate the distribution of cloud-cover amounts and the correlation of cloud cover in time and space. The correlation between observations at the ...

P. A. Jones

1992-07-01T23:59:59.000Z

455

OPTICAL-TO-NEAR-INFRARED SIMULTANEOUS OBSERVATIONS FOR THE HOT URANUS GJ3470b: A HINT OF A CLOUD-FREE ATMOSPHERE  

SciTech Connect

We present optical (g', R{sub c}, and I{sub c}) to near-infrared (J) simultaneous photometric observations for a primary transit of GJ3470b, a Uranus-mass transiting planet around a nearby M dwarf, by using the 50 cm MITSuME telescope and the 188 cm telescope, both at the Okayama Astrophysical Observatory. From these data, we derive the planetary mass, radius, and density as 14.1 {+-} 1.3 M{sub Circled-Plus }, 4.32{sup +0.21}{sub -0.10} R{sub Circled-Plus }, and 0.94 {+-} 0.12 g cm{sup -3}, respectively, thus confirming the low density that was reported by Demory et al. based on the Spitzer/IRAC 4.5 {mu}m photometry (0.72{sup +0.13}{sub -0.12} g cm{sup -3}). Although the planetary radius is about 10% smaller than that reported by Demory et al., this difference does not alter their conclusion that the planet possesses a hydrogen-rich envelope whose mass is approximately 10% of the planetary total mass. On the other hand, we find that the planet-to-star radius ratio (R{sub p} /R{sub s} ) in the J band (0.07577{sup +0.00072}{sub -0.00075}) is smaller than that in the I{sub c} (0.0802 {+-} 0.0013) and 4.5 {mu}m (0.07806{sup +0.00052}{sub -0.00054}) bands by 5.8% {+-} 2.0% and 2.9% {+-} 1.1%, respectively. A plausible explanation for the differences is that the planetary atmospheric opacity varies with wavelength due to absorption and/or scattering by atmospheric molecules. Although the significance of the observed R{sub p} /R{sub s} variations is low, if confirmed, this fact would suggest that GJ3470b does not have a thick cloud layer in the atmosphere. This property would offer a wealth of opportunity for future transmission-spectroscopic observations of this planet to search for certain molecular features, such as H{sub 2}O, CH{sub 4}, and CO, without being prevented by clouds.

Fukui, Akihiko; Yanagisawa, Kenshi; Kuroda, Daisuke; Shimizu, Yasuhiro; Izumiura, Hideyuki [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Narita, Norio; Takahashi, Yasuhiro H.; Kawauchi, Kiyoe; Nagayama, Shogo [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kurosaki, Kenji; Ikoma, Masahiro [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033 (Japan); Ohnuki, Hiroshi [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Onitsuka, Masahiro; Suenaga, Takuya [The Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirano, Teruyuki [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ohta, Kouji [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502 (Japan); Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawai, Nobuyuki, E-mail: afukui@oao.nao.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro, Tokyo 152-8551 (Japan)

2013-06-20T23:59:59.000Z

456

Fine Structure of Cloud Droplet Concentration as Seen from the Fast-FSSP Measurements. Part II: Results of In Situ Observations  

Science Conference Proceedings (OSTI)

A new feature of cloud structure has been discovered while analyzing the measurements obtained in situ in 57 clouds by the Fast Forward-Scattering Spectrometer Probe (FSSP). By means of a novel technique of statistical analysis, it is shown that ...

M. Pinsky; A. Khain

2003-01-01T23:59:59.000Z

457

Solar Radiative Transfer in Clouds with Vertical Internal Inhomogeneity  

Science Conference Proceedings (OSTI)

To investigate the photon transport in inhomogeneous clouds, a Monte Carlo cloud model with internal variation of optical properties is developed. The data for cloud vertical internal inhomogeneity are chosen from published observations. ...

J. Li; D. J. W. Geldart; Petr Chýlek

1994-09-01T23:59:59.000Z

458

On the Relationship between Thermodynamic Structure and Cloud Top, and Its Climate Significance in the Arctic  

Science Conference Proceedings (OSTI)

Cloud and thermodynamic characteristics from three Arctic observation sites are investigated to understand the collocation between low-level clouds and temperature inversions. A regime where cloud top was 100–200 m above the inversion base [cloud ...

Joseph Sedlar; Matthew D. Shupe; Michael Tjernström

2012-04-01T23:59:59.000Z

459

Cloud-Base Height Estimates Using a Combination of Meteorological Satellite Imagery and Surface Reports  

Science Conference Proceedings (OSTI)

This paper describes how the combination of a satellite-derived cloud classification with surface observations can improve analysis of cloud-base height. A cloud-base retrieval that combines a cloud classification derived from visible and ...

John M. Forsythe; Thomas H. Vonder Haar; Donald L. Reinke

2000-12-01T23:59:59.000Z

460

Boundary Layer and Cloud Structure Controls on Tropical Low Cloud Cover Using A-Train Satellite Data and ECMWF Analyses  

Science Conference Proceedings (OSTI)

The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), CloudSat radar, and the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud data on the A-Train constellation complemented with the European Centre for ...

Terence L. Kubar; Duane E. Waliser; J-L. Li

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "observed cirrus cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Cloud Chmabers  

NLE Websites -- All DOE Office Websites (Extended Search)

Video - (Requires Windows Media Player) Build your own cloud chamber - Instructions Project Contact: Tom Jordan Web Maintainer: qnet-webmaster@fnal.gov Last Update: May 31, 2011...

462

Understanding the AIRS, ARM, and MODIS cloud products by cross-comparison  

NLE Websites -- All DOE Office Websites (Extended Search)

Understanding the AIRS, ARM, and MODIS cloud products by cross-comparison Understanding the AIRS, ARM, and MODIS cloud products by cross-comparison Kahn, Brian Jet Propulsion Laboratory Eldering, Annmarie Jet Propulsion Laboratory Category: Cloud Properties We present comparisons of the Atmospheric Infrared Sounder (AIRS) operational cloud top height (CTH) to the active surface-based measurements of the Atmospheric Radiation Measurement (ARM) program sites in the tropical Western Pacific. The agreement is found to be consistent to other comparisons of passive IR-derived CTH from other measurement platforms despite the nominal footprint size of 45 km at nadir view. Independent comparisons of CTH to the millimeter-wave cloud radar at Manus Island and the micropulse lidar at Nauru Island indicate that the CTH retrieved by AIRS is statistically significant at the 5% level or less for cirrus cases

463

Improving Retrievals of Cirrus Cloud Particle Size Coupling Lidar and Three-Channel Radiometric Techniques  

Science Conference Proceedings (OSTI)

This study is intended to illustrate the potential advantage of combining lidar measurements and the split-window technique based on the infrared spectral information contained at the 8.65-, 11.15-, and 12.05-?m bands for inferring the ...

M. Chiriaco; H. Chepfer; V. Noel; A. Delaval; M. Haeffelin; P. Dubuisson; P. Yang

2004-07-01T23:59:59.000Z

464

Radiative Transfer in Cirrus Clouds. Part III: Light Scattering by Irregular Ice Crystals  

Science Conference Proceedings (OSTI)

A new Monte Carlo/geometric ray-tracing method has been developed for the computation of the scattering, absorption, and polarization properties of ice crystals with various irregular structure, including hollow columns, bullet rosettes, ...

Y. Takano; K. N. Liou

1995-04-01T23:59:59.000Z

465

Remote sensing of cirrus cloud particle size and optical depth using polarimetric sensor measurements  

E-Print Network (OSTI)

M. Cai, 1991: Scattering phase matrices of ice crystals with44 For nonspherical ice crystals, the phase function, P 11 ,hexagonal ice crystals and compared phase-matrix elements

Ou, Szu-cheng C; Liou, K N; Takano, Y; Slonaker, R L

2005-01-01T23:59:59.000Z

466

A General Approach for Deriving the Properties of Cirrus and Stratiform Ice Cloud Particles  

Science Conference Proceedings (OSTI)

A new approach is described for calculating the mass (m) and terminal velocity (Vt) of ice particles from airborne and balloon-borne imaging probe data as well as its applications for remote sensing and modeling studies. Unlike past studies that ...

Andrew J. Heymsfield; Sharon Lewis; Aaron Bansemer; Jean Iaquinta; Larry M. Miloshevich; Masahiro Kajikawa; Cynthia Twohy; Michael R. Poellot

2002-01-01T23:59:59.000Z

467

Stratospheric Ion and Aerosol Chemistry and Possible Links with Cirrus Cloud Microphysics—A Critical Assessment  

Science Conference Proceedings (OSTI)

It has been postulated that variations in galactic cosmic rays could affect production of stratospheric aerosols which, after transport to the upper troposphere, could affect latent heat release in convective and cyclonic systems. This hypothesis ...

Volker A. Mohnen

1990-08-01T23:59:59.000Z

468

Cloud Detection with MODIS. Part II: Validation  

Science Conference Proceedings (OSTI)

An assessment of the performance of the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask algorithm for Terra and Aqua satellites is presented. The MODIS cloud mask algorithm output is compared with lidar observations from ground [...

S. A. Ackerman; R. E. Holz; R. Frey; E. W. Eloranta; B. C. Maddux; M. McGill

2008-07-01T23:59:59.000Z

469

Cloud Color and Ocean Radiant Heating  

Science Conference Proceedings (OSTI)

It is well recognized that clouds regulate the flux of solar radiation reaching the sea surface. Clouds also affect the spectral distribution of incident irradiance. Observations of spectral and total incident solar irradiance made from the ...

David A. Siegel; Toby K. Westberry; J. Carter Ohlmann

1999-04-01T23:59:59.000Z

470

Radar and Radiation Properties of Ice Clouds  

Science Conference Proceedings (OSTI)

The authors derive relations of the equivalent radar reflectivity Ze and extinction coefficient ? of ice clouds and confirm the theory by in situ aircraft observations during the First International Satellite Cloud Climatology Project Regional ...

David Atlas; Sergey Y. Matrosov; Andrew J. Heymsfield; Ming-Dah Chou; David B. Wolff

1995-11-01T23:59:59.000Z

471

Precipitation and Cloud Structure in Midlatitude Cyclones  

Science Conference Proceedings (OSTI)

Composite mean fields and probability distribution functions (PDFs) of rain rate, cloud type and cover, cloud-top temperature, surface wind velocity, and water vapor path (WVP) are constructed using satellite observations of midlatitude cyclones ...

Paul R. Field; Robert Wood

2007-01-01T23:59:59.000Z

472

Cellular clouds  

Science Conference Proceedings (OSTI)

This paper progresses an analysis of what it means to be a cellular network operator and what form the ownership and control of future cellular networks may take. Alternative modes of ownership may allow for the creation of more flexible cellular networking ... Keywords: Cellular Cloud, Cellular network, Cloud Computing, Cognitive radio, DSA, LTE, MVNO, Services, Utility Cellular Network

Tim Forde; Linda Doyle

2013-03-01T23:59:59.000Z

473

Comparison of Model-Predicted Transport and Diffusion of Seeding Material with NOAA Satellite-Observed Seeding Track in Supercooled Layer Clouds  

Science Conference Proceedings (OSTI)

From 0615 to 0749 UTC 14 March 2000, an operation of cloud seeding for precipitation enhancement by aircraft was carried out in the middle part of Shaanxi Province, China. National Oceanic and Atmospheric Administration (NOAA)-14 satellite ...

Xing Yu; Jin Dai; Daniel Rosenfeld; Hengchi Lei; Xiaohong Xu; Peng Fan; Zhengqi Chen

2005-06-01T23:59:59.000Z

474

Obtaining Best Estimates for the Microphysical and Radiative Properties of Tropical Ice Clouds from TWP-ICE In Situ Microphysical Observations  

Science Conference Proceedings (OSTI)

Best estimates of the bulk microphysical and radiative properties (ice water content, visible extinction, effective radius, and total concentration) are derived for three case studies of tropical ice clouds sampled during the Tropical Warm Pool ...

A. Protat; G. M. McFarquhar; J. Um; J. Delanoë

2011-04-01T23:59:59.000Z

475

Full-Time, Eye-Safe Cloud and Aerosol Lidar Observation at Atmospheric Radiation Measurement Program Sites: Instruments and Data Processing  

Science Conference Proceedings (OSTI)

Atmospheric radiative forcing, surface radiation budget, and top-of-the-atmosphere radiance interpretation involve knowledge of the vertical height structure of overlying cloud and aerosol layers. During the last decade, the U.S. Department of ...

James R. Campbell; Dennis L. Hlavka; Ellsworth J. Welton; Connor J. Flynn; David D. Turner; James D. Spinhirne; V. Stanley Scott III; I. H. Hwang

2002-04-01T23:59:59.000Z

476

Warm Core Structures in Organized Cloud Clusters Developing or Not Developing into Tropical Storms Observed by the Advanced Microwave Sounding Unit  

Science Conference Proceedings (OSTI)

The temperature profiles of organized cloud clusters developing or not developing (nondeveloping) into tropical storms (TSs; maximum surface wind >34 kt) over the western North Pacific in 2004 were investigated using Advanced Microwave Sounding ...

Kotaro Bessho; Tetsuo Nakazawa; Shuji Nishimura; Koji Kato

2010-07-01T23:59:59.000Z

477

A Bootstrap Technique for Testing the Relationship between Local-Scale Radar Observations of Cloud Occurrence and Large-Scale Atmospheric Fields  

Science Conference Proceedings (OSTI)

A classification scheme is created to map the synoptic-scale (large scale) atmospheric state to distributions of local-scale cloud properties. This mapping is accomplished by a neural network that classifies 17 months of synoptic-scale initial ...

Roger Marchand; Nathaniel Beagley; Sandra E. Thompson; Thomas P. Ackerman; David M. Schultz

2006-11-01T23:59:59.000Z

478

XMM-Newton observations of the Small Magellanic Cloud: X-ray outburst of the 6.85 s pulsar XTE J0103-728  

E-Print Network (OSTI)

A bright X-ray transient was seen during an XMM-Newton observation in the direction of the Small Magellanic Cloud (SMC) in October 2006. The EPIC data allow us to accurately locate the source and to investigate its temporal and spectral behaviour. X-ray spectra covering 0.2-10 keV and pulse profiles in different energy bands were extracted from the EPIC data. The detection of 6.85 s pulsations in the EPIC-PN data unambiguously identifies the transient with XTE J0103-728, discovered as 6.85 s pulsar by RXTE. The X-ray light curve during the XMM-Newton observation shows flaring activity of the source with intensity changes by a factor of two within 10 minutes. Modelling of pulse-phase averaged spectra with a simple absorbed power-law indicates systematic residuals which can be accounted for by a second emission component. For models implying blackbody emission, thermal plasma emission or emission from the accretion disk (disk-blackbody), the latter yields physically sensible parameters. The photon index of the power-law of ~0.4 indicates a relatively hard spectrum. The 0.2-10 keV luminosity was 2x10^{37} with a contribution of ~3% from the disk-blackbody component. A likely origin for the excess emission is reprocessing of hard X-rays from the neutron star by optically thick material near the inner edge of an accretion disk. From a timing analysis we determine the pulse period to 6.85401(1) s indicating an average spin-down of ~0.0017 s per year since the discovery of XTE J0103-728 in May 2003. The X-ray properties and the identification with a Be star confirm XTE J0103-728 as Be/X-ray binary transient in the SMC.

F. Haberl; W. Pietsch

2008-01-30T23:59:59.000Z

479

Microphysical Observations of Tropical Clouds  

Science Conference Proceedings (OSTI)

The results from airborne in situ sampling of convective tropical storms in the Amazon and Kwajalein are presented. Three cases from the Amazon and two from Kwajalein are compared and provide examples of the much larger dataset that was obtained ...

Jeffrey L. Stith; James E. Dye; Aaron Bansemer; Andrew J. Heymsfield; Cedric A. Grainger; Walter A. Petersen; Robert Cifelli

2002-02-01T23:59:59.000Z

480

Improvements in Representations of Cloud Microphysics for BBHRP and Models using Data Collected during M-PACE and TWP-ICE  

SciTech Connect

In our research we proposed to use data collected during the 2004 Mixed-Phase Arctic Cloud Experiment (MPACE) and the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE) to improve retrievals of ice and mixed-phase clouds, to improve our understanding of how cloud and radiative processes affect cloud life cycles, and to develop and test methods for using ARM data more effectively in model. In particular, we proposed to: 1) use MPACE in-situ data to determine how liquid water fraction and cloud ice and liquid effective radius (r{sub ei} and r{sub ew}) vary with temperature, normalized cloud altitude and other variables for Arctic mixed-phase clouds, and to use these data to evaluate the performance of model parameterization schemes and remote sensing retrieval algorithms; 2) calculate rei and size/shape distributions using TWP-ICE in-situ data, investigate their dependence on cirrus type (oceanic or continental anvils or cirrus not directly traced to convection), and develop and test representations for MICROBASE; 3) conduct fundamental research enhancing our understanding of cloud/radiative interactions, concentrating on effects of small crystals and particle shapes and sizes on radiation; and 4) improve representations of microphysical processes for models (fall-out, effective density, mean scattering properties, rei and rew) and provide them to ARM PIs. In the course of our research, we made substantial progress on all four goals.

Greg M. McFarquhar

2010-02-22T23:59:59.000Z

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481

Cumulus Clouds and Reflected Sunlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Cumulus Clouds and Reflected Sunlight Cumulus Clouds and Reflected Sunlight from Landsat ETM+ G. Wen and L. Oreopoulos National Aeronautics and Space Administration Goddard Space Flight Center University of Maryland Baltimore County Joint Center of Earth System Technology Greenbelt, Maryland R. F. Cahalan and S. C. Tsay National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland Introduction Cumulus clouds attenuate solar radiation casting shows on the ground. Cumulus clouds can also enhance solar radiation in the clear region nearby. The enhancement of down-welling solar radiation has been observed at the ground level in the clear region near cumulus clouds (Mims and Frederick 1994). The additional diffuse radiation source from cumulus clouds makes the clear gaps appear to be

482

Hole-boring through clouds for laser power beaming  

Science Conference Proceedings (OSTI)

Power beaming to satellites with a ground-based laser can be limited by clouds. Hole-boring through the clouds with a laser has been proposed as a way to overcome this obstacle. This paper reviews the past work on laser hole-boring and concludes that hole-boring for direct beaming to satellites is likely to require 10--100 MW. However, it may be possible to use an airborne relay mirror at 10--25 km altitude for some applications in order to extend the range of the laser (e.g., for beaming to satellites near the horizon). In these cases, use of the relay mirror also would allow a narrow beam between the laser and the relay, as well as the possibility of reducing the crosswind if the plane matched speed with the cloud temporarily. Under these conditions, the power requirement to bore a hole through most cirrus and cirrostratus clouds might be only 500-kW if the hole is less than 1 m in diameter and if the crosswind speed is less than 10 m/s. Overcoming cirrus and cirrostratus clouds would reduce the downtime due to weather by a factor of 2. However, 500 kW is a large laser, and it may be more effective instead to establish a second power beaming site in a separate weather zone. An assessment of optimum wavelengths for hole boring also was made, and the best options were found to be 3.0--3.4 {mu}m and above 10 {mu}m.

Lipinski, R.J. [Sandia National Labs., Albuquerque, NM (United States); Walter, R.F. [W.J. Schafer Associates, Inc., Albuquerque, NM (United States)

1994-12-31T23:59:59.000Z

483

Thin Cloud Length Scales Using CALIPSO and CloudSat Data  

E-Print Network (OSTI)

Thin clouds are the most difficult cloud type to observe. The recent availability of joint cloud products from the active remote sensing instruments aboard CloudSat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) facilitates the study of these clouds. Using one of these joint cloud products, 2B-GEOPROF-Lidar, and a post-processing algorithm designed to find horizontally continuous thin clouds within the cloud product, the locations, length scales, and vertical distributions by length of thin clouds are determined. It is found that thin clouds vary in length from a few km to over 2900 km and tend to be longer in the tropical upper troposphere than lower in the atmosphere and at higher latitudes. In the upper troposphere between 0° and 40°N, over 20% of all thin cloud measurements in the 2B-GEOPROF-Lidar product are contributed by thin clouds that are longer than 500 km. In fact, in this latitude range, over 65% of all thin cloud measurements are contributed by clouds longer than 100 km. Also, thin cloud length and frequency differ between the four seasons in the year of data used here.

Solbrig, Jeremy E.

2009-08-01T23:59:59.000Z

484

Relationships between Total Water, Condensed Water, and Cloud Fraction in Stratiform Clouds Examined Using Aircraft Data  

Science Conference Proceedings (OSTI)

Relationships among total water, condensed water, and cloud fraction in boundary layer and cold tropospheric stratiform clouds are investigated using a large observational dataset collected by the U.K. Met. Office C-130 aircraft. Values of the ...

Robert Wood; Paul R. Field

2000-06-01T23:59:59.000Z

485

ARM - Measurement - Cloud condensation nuclei  

NLE Websites -- All DOE Office Websites (Extended Search)

condensation nuclei condensation nuclei ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud condensation nuclei Small particles (typically 0.0002 mm, or 1/100 th the size of a cloud droplet) about which cloud droplets coalesce. Categories Aerosols, Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CCN : Cloud Condensation Nuclei Particle Counter Field Campaign Instruments AOS : Aerosol Observing System

486

AIRS Subpixel Cloud Characterization Using MODIS Cloud Products  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) measurements from the Earth Observing System's (EOS's) Aqua satellite enable improved global monitoring of the distribution of clouds. MODIS is ...

Jun Li; W. Paul Menzel; Fengying Sun; Timothy J. Schmit; James Gurka

2004-08-01T23:59:59.000Z

487

Microphysical Effects of Wintertime Cloud Seeding with Silver Iodide over the Rocky Mountains. Part III: Observations over the Grand Mesa, Colorado  

Science Conference Proceedings (OSTI)

During March 1986, several airborne and ground-based silver iodide (AgI) seeding experiments were conducted over the Grand Mesa, Colorado, during a three-day period of northerly flow and shallow orographic cloud. While little natural snowfall was ...

Arlin B. Super; Bruce A. Boe

1988-10-01T23:59:59.000Z

488

Cloud-to-Ground Lightning Activity in the 10–11 June 1985 Mesoscale Convective System Observed during the Oklahoma–Kansas PRE-STORM Project  

Science Conference Proceedings (OSTI)

As part of the field program for the Oklahoma–Kansas PRE-STORM Project conducted in May–June 1985, a network of electromagnetic direction-finders was deployed to locate and detect the polarity of cloud-to-ground (CG) lighting flashes associated ...

Steven A. Rutledge; Donald R. MacGorman

1988-07-01T23:59:59.000Z

489

Cloud computing beyond objects: seeding the cloud  

Science Conference Proceedings (OSTI)

Cloud computing is an emerging computing milieu which dynamically enables scalable and virtually unlimited resources. This panel will discuss emerging tools, skills and technologies that will ""seed the cloud"" - enabling improved interoperability, security, ... Keywords: cloud computing, skills, technologies, tools

Steven Fraser; Robert Biddle; Scott Jordan; Kate Keahey; Bob Marcus; E. Michael Maximilien; Dave Thomas

2009-10-01T23:59:59.000Z

490

ARM - Field Campaign - Spring Cloud IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsSpring Cloud IOP govCampaignsSpring Cloud IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Spring Cloud IOP 2000.03.01 - 2000.03.26 Lead Scientist : Gerald Mace For data sets, see below. Summary The Atmospheric Radiation Measurement (ARM) Program conducted a Cloud Intensive Operational Period (IOP) in March 2000 that was the first-ever effort to document the 3-dimensional cloud field from observational data. Prior numerical studies of solar radiation propagation through the atmosphere in the presence of clouds have been limited by the necessity to use theoretical rep