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Climate & Radiation
Geodesy and Geophysics
Wallops Field Support
Branch Seminar Series: Robin Hogan
Dept. of Meteorology, University of Reading, Reading, UK
Tuesday, February 3, 2009 - 22:30
The accurate representation of clouds in radiation schemes is crucial for climate prediction, yet substantial biases still remain due to unrepresented cloud structure. I this talk I will first discuss results from radar to characterize cloud vertical overlap and horizontal heterogeneity. I will then present a new method for representing these properties efficiently in a radiation scheme, and use it to estimate the global effect on cloud radiative forcing. Considerable regional structure is found in the change to net forcing; in marine stratocumulus regions the shortwave horizontal inhomogeneity effect is dominant, while in the Pacific Warm Pool region, there is a large degree of cancellation between the effects of inhomogeneity and overlap. Finally the issue of three-dimensional radiative transfer will be addressed, including a new method to represent radiative transport through cloud sides by modifying the two-stream equations of radiative transfer at a fundamental level.