Recorded presentation14B.1
A Test of the Simulation of Tropical Convective Cloudiness by a Cloud-Resolving Model
Dennis L. Hartmann, University of Washington, Seattle, WA; and M. A. Lopez, P. N. Blossey, R. Wood, C. S. Bretherton, and T. L. Kubar
The distribution of tropical high clouds produced by a doubly periodic three-dimensional cloud resolving model is compared with satellite observations. The model is forced with steady forcing characteristic of tropical Pacific convective regions, and the model clouds are compared with satellite observations for the same regions. Clouds are divided into categories that represent convective cores, moderately thick anvil clouds and thin high clouds. The statistics of these clouds and their relationship to the precipitation rate are computed in a similar way for the model data and for observations from the MODIS and AMSR instruments on the Aqua Satellite. The model produces a good simulation of the relationship between the precipitation rate and optically thick cold clouds that represent convective cores. The model also does a reasonable job of simulating the abundance of thin cold clouds in the East and West Pacific ITCZ regions. The model produces too little anvil cloud by a factor of about 4, however. The observations show probability density functions for OLR and albedo with maxima that correspond to extended upper level cold clouds, whereas the model does not. The sensitivity to model parameters of the simulation of anvil cloud area per unit of precipitation is explored using a two-dimensional model. Recorded presentation
Session 14B, Climate Modeling and Diagnostics Part II
Thursday, 24 January 2008, 11:00 AM-12:15 PM, 217-218
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