Impact of cloud microphysics on cloud-radiation interactions in the CSU general circulation model

Conference · Sat Apr 01 04:00:00 EST 1995

OSTI ID:67724

Fowler, L D; Randall, D A

Our ability to study and quantify the impact of cloud-radiation interactions in studying global scale climate variations strongly relies upon the ability of general circulation models (GCMs) to simulate the coupling between the spatial and temporal variations of the model-generated cloudiness and atmospheric moisture budget components. In particular, the ability of GCMs to reproduce the geographical distribution of the sources and sinks of the planetary radiation balance depends upon their representation of the formation and dissipation of cloudiness in conjunction with cloud microphysics processes, and the fractional amount and optical characteristics of cloudiness in conjunction with the mass of condensate stored in the atmosphere. A cloud microphysics package which encompasses five prognostic variables for the mass of water vapor, cloud water, cloud ice, rain, and snow has been implemented in the Colorado State University General Circulation Model (CSU GCM) to simulate large-scale condensation processes. Convection interacts with the large-scale environment through the detrainment of cloud water and cloud ice at the top of cumulus towers. The cloud infrared emissivity and cloud optical depth of the model-generated cloudiness are interactive and depend upon the mass of cloud water and cloud ice suspended in the atmosphere. The global atmospheric moisture budget and planetary radiation budget of the CSU GCM obtained from a perpetual January simulation are discussed. Geographical distributions of the atmospheric moisture species are presented. Global maps of the top-of-atmosphere outgoing longwave radiation and planetary albedo are compared against Earth Radiation Budget Experiment (ERBE) satellite data.

• Research Organization: Colorado State Univ., Fort Collins, CO (United States). Dept. of Atmospheric Science
• Sponsoring Organization: USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: FG02-91ER61218
• OSTI ID: 67724
• Report Number(s): CONF-940115--33; ON: DE95008979; CNN: Grant ATM-8907414
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
ATMOSPHERIC CIRCULATION
ATMOSPHERIC PRECIPITATIONS
CLIMATE MODELS
CLOUDS
EARTH ATMOSPHERE
GENERAL CIRCULATION MODELS
RADIATION BELTS
SIMULATION
VAPOR CONDENSATION