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Title: Modeling of clouds and radiation for developing parameterizations for general circulation models. Annual report, 1994

Abstract

We are using a hierarchy of numerical models of cirrus and stratus clouds and radiative transfer to improve the reliability of general circulation models. Our detailed cloud microphysical model includes all of the physical processes believed to control the lifecycle of liquid and ice clouds in the troposphere. In our one-dimensional cirrus studies, we find that the ice crystal number and size in cirrus clouds are not very sensitive to the number of condensation nuclei which are present. We have compared our three-dimensional meoscale simulations of cirrus clouds with radar, lidar satellite and other observations of water vapor and cloud fields and find that the model accurately predicts the characteristics of a cirrus cloud system. The model results reproduce several features detected by remote sensing (lidar and radar) measurements, including the appearance of the high cirrus cloud at about 15 UTC and the thickening of the cloud at 20 UTC. We have developed a new parameterizations for production of ice crystals based on the detailed one-dimensional cloud model, and are presently testing the parameterization in three-dimensional simulations of the FIRE-II November 26 case study. We have analyzed NWS radiosonde humidity data from FIRE and ARM and found errors, biases, andmore » uncertainties in the conversion of the sensed resistance to humidity.« less

Publication Date:
Research Org.:
National Aeronautics and Space Administration, Washington, DC (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
272200
Report Number(s):
DOE/ER/61743-T1
ON: DE96013009
DOE Contract Number:
AI03-94ER61743
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: [1994]
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CLOUDS; MATHEMATICAL MODELS; ATMOSPHERIC CIRCULATION; CLIMATIC CHANGE; WEATHER; CLIMATES; ENVIRONMENT; TROPOSPHERE; AEROSOLS; ICE; REMOTE SENSING; PROGRESS REPORT

Citation Formats

NONE. Modeling of clouds and radiation for developing parameterizations for general circulation models. Annual report, 1994. United States: N. p., 1994. Web. doi:10.2172/272200.
NONE. Modeling of clouds and radiation for developing parameterizations for general circulation models. Annual report, 1994. United States. doi:10.2172/272200.
NONE. 1994. "Modeling of clouds and radiation for developing parameterizations for general circulation models. Annual report, 1994". United States. doi:10.2172/272200. https://www.osti.gov/servlets/purl/272200.
@article{osti_272200,
title = {Modeling of clouds and radiation for developing parameterizations for general circulation models. Annual report, 1994},
author = {NONE},
abstractNote = {We are using a hierarchy of numerical models of cirrus and stratus clouds and radiative transfer to improve the reliability of general circulation models. Our detailed cloud microphysical model includes all of the physical processes believed to control the lifecycle of liquid and ice clouds in the troposphere. In our one-dimensional cirrus studies, we find that the ice crystal number and size in cirrus clouds are not very sensitive to the number of condensation nuclei which are present. We have compared our three-dimensional meoscale simulations of cirrus clouds with radar, lidar satellite and other observations of water vapor and cloud fields and find that the model accurately predicts the characteristics of a cirrus cloud system. The model results reproduce several features detected by remote sensing (lidar and radar) measurements, including the appearance of the high cirrus cloud at about 15 UTC and the thickening of the cloud at 20 UTC. We have developed a new parameterizations for production of ice crystals based on the detailed one-dimensional cloud model, and are presently testing the parameterization in three-dimensional simulations of the FIRE-II November 26 case study. We have analyzed NWS radiosonde humidity data from FIRE and ARM and found errors, biases, and uncertainties in the conversion of the sensed resistance to humidity.},
doi = {10.2172/272200},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month =
}

Technical Report:

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  • We have used a hierarchy of numerical models for cirrus and stratus clouds and for radiative transfer to improve the reliability of general circulation models. Our detailed cloud microphysical model includes all of the physical processes believed to control the lifecycles of liquid and ice clouds in the troposphere. We have worked on specific GCM parameterizations for the radiative properties of cirrus clouds, making use of a mesocale model as the test-bed for the parameterizations. We have also modeled cirrus cloud properties with a detailed cloud physics model to better understand how the radiatively important properties of cirrus are controlledmore » by their environment. We have used another cloud microphysics model to investigate of the interactions between aerosols and clouds. This work is some of the first to follow the details of interactions between aerosols and cloud droplets and has shown some unexpected relations between clouds and aerosols. We have also used line-by- line radiative transfer results verified with ARM data, to derive a GCMS.« less
  • We conducted modeling work in radiative transfer and cloud microphysics. Our work in radiative transfer included performance tests to other high accuracy methods and to measurements under cloudy, partial cloudy and cloud-free conditions. Our modeling efforts have been aimed to (1) develop an accurate and rapid radiative transfer model; (2) develop three-dimensional radiative transfer models; and (3) develop microphysics resolving cloud and aerosol models. We applied our models to investigate solar clear-sky model biases, investigate aerosol direct effects, investigate aerosol indirect effects, investigate microphysical properties of cirrus, investigate microphysical properties of stratus, investigate relationships between cloud properties, and investigate themore » effects of cloud structure.« less
  • DOE has launched a major initiative -- the Atmospheric Radiation Measurements (ARM) Program -- directed at improving the parameterization of the physics governing cloud and radiative processes in general circulation models (GCMs). One specific goal of ARM is to improve the treatment of radiative transfer in GCMs under clear-sky, general overcast and broken cloud conditions. In 1990, the authors proposed to contribute to this goal by attacking major problems connected with one of the dominant radiation components of the problem -- longwave radiation. In particular, their long-term research goals are to: develop an optimum longwave radiation model for use inmore » GCMs that has been calibrated with state-of-the-art observations, assess the impact of the longwave radiative forcing in a GCM, determine the sensitivity of a GCM to the radiative model used in it, and determine how the longwave radiative forcing contributes relatively when compared to shortwave radiative forcing, sensible heating, thermal advection and expansion.« less
  • One of the biggest uncertainties associated with climate models and climate forcing is the treatment of aerosols and their effects on clouds. The effect of aerosols on clouds can be divided into two components: The first indirect effect is the forcing associated with increases in droplet concentrations; the second indirect effect is the forcing associated with changes in liquid water path, cloud morphology, and cloud lifetime. Both are highly uncertain. This project applied a cloud-resolving model to understand the response of clouds under a variety of conditions to changes in aerosols. These responses are categorized according to the large-scale meteorologicalmore » conditions that lead to the response. Meteorological conditions were sampled from various fields, which, together with a global aerosol model determination of the change in aerosols from present day to pre-industrial conditions, was used to determine a first order estimate of the response of global cloud fields to changes in aerosols. The response of the clouds in the NCAR CAM3 GCM coupled to our global aerosol model were tested by examining whether the response is similar to that of the cloud resolving model and methods for improving the representation of clouds and cloud/aerosol interactions were examined.« less
  • 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,more » 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.« less