Geophysical Research Letters

Climatology of a nonhydrostatic global model with explicit cloud processes

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Abstract

[1] This is the first study to obtain a statistical climate state under a perpetual July condition using a nonhydrostatic global model with explicit cloud processes. Horizontal grid intervals of approximately 7 and 14 km over the globe marginally allowed for a general representation of meso-scale circulations associated with deep clouds. The fine-scale precipitation distribution was similar to satellite observations, particularly in regions of the Intertropical Convergence Zone. Realistic distributions of cloud cover in upper, middle, and lower levels were also obtained, although the geographic locations of lower clouds differed slightly from observations over the eastern Pacific. Sensitivity experiments revealed a decrease in outgoing longwave radiation (OLR) as ice fall speed increased or as mixing in the boundary layer was enhanced. As the horizontal resolution increased, the cloud fraction increased and both the OLR and the total water path decreased, implying that cloud overlap also decreased as the resolution increased.

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