HR: 16:50h
AN: A44B-03 INVITED     [Abstracts]
TI: Cloud microphysics in the GFDL AGCM: current status and future developments
AU: * Golaz, J
EM: Chris.Golaz@noaa.gov
AF: Geophysical Fluid Dynamics Laboratory / NOAA, Princeton University Forrestal Campus Post Office Box 308, Princeton, NJ 08542, United States
AU: Donner, L J
EM: Leo.J.Donner@noaa.gov
AF: Geophysical Fluid Dynamics Laboratory / NOAA, Princeton University Forrestal Campus Post Office Box 308, Princeton, NJ 08542, United States
AU: Ming, Y
EM: Yi.Ming@noaa.gov
AF: Geophysical Fluid Dynamics Laboratory / NOAA, Princeton University Forrestal Campus Post Office Box 308, Princeton, NJ 08542, United States
AU: Zhao, M
EM: Ming.Zhao@noaa.gov
AF: Geophysical Fluid Dynamics Laboratory / NOAA, Princeton University Forrestal Campus Post Office Box 308, Princeton, NJ 08542, United States
AB: Cloud microphysics impacts various aspects of an atmospheric general circulation model (AGCM). An overview of the cloud microphysics parameterizations in the current version of the GFDL AGCM will be presented. Representation of microphysical processes are included in the convective parameterizations (shallow and deep) as well as the stratiform cloud scheme. Current convection schemes incorporate highly simplified formulations for the microphysical processes leading to the formation of precipitation. These convection schemes are being replaced by more sophisticated ones with explicit prediction of cloud plumes vertical velocities. This allows for the inclusion of single- or double-moment microphysics schemes as part of the convective parameterizations. The stratiform cloud scheme currently incorporates a single-moment microphysics and is being updated to a partly double-moment formulation. Of particular importance for the next version of the GFDL AGCM is the treatment of the aerosol indirect effect. Activation of cloud condensation nuclei to form cloud droplets is determined by local supersaturation, which is primarily controlled by cloud vertical velocities. Such velocities are not readily available in a large-scale model. Avenues under consideration for the parameterization of aerosol activation in the AGCM convective and stratiform parameterizations will be discussed.
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly