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Heng Xiao

2012-09-19
15:00:00 - 17:00:00

308 , Mathematics Research Center Building (ori. New Math. Bldg.)

Cloud feedback is the largest contributor of uncertainty in climate projections. Marine low clouds in turn contribute the most to the inter-model spread of global mean cloud feedback among IPCC AR4 models. This talk focuses on the simulation of marine low clouds in current generation climate models. In the first part of the talk we discuss deficiencies in the simulation of subtropical marine low clouds by the NCAR CESM and the NCEP GFS and recent improvements to the shallow convection parameterization in the NCEP GFS implemented by the NOAA Stratocumulus-to- cumulus transition Climate Process Team. In the second part, we present the design and implementation of a new treatment for the stratocumulus-to-cumulus transition in the UCLA AGCM. We also discuss the implications of parameter sensitivity found in these models.