Integration of a prognostic sea surface skin temperature scheme into weather and climate models

A prognostic skin sea surface temperature (SST) algorithm is included in the Community Atmosphere Model (CAM3.1). With this algorithm, the model produces a mean diurnal cycle of < 0.5 K over most oceanic regions and > 0.5 K primarily in tropical and subtropical oceans of the summer hemisphere with isolated areas of > 2 K. The diurnal cycle in air temperature is substantially increased over regions with large skin SST diurnal cycles, and the enhanced diurnal cycle agrees better with the TAO buoy data over the equatorial Pacific. There is also a significant effect on the diurnal cycle in precipitation particularly in the increased hourly maximum precipitation over the Bay of Bengal and the western Pacific in boreal summer. These changes to the diurnal cycle in SST affect the seasonal climatologies in the model with improved seasonal mean precipitation mainly in the tropics following similar patterns to the hourly maximum precipitation rates. The near-surface flow across the Indian subcontinent is also increased during the summer monsoon resulting in higher seasonal precipitation over the Bay of Bengal.