Local rainfall-SST relationship on subseasonal time scales in satellite observations and CFS

Abstract

The present study documents local rainfall-SST relationship on subseasonal time scales in the tropical Indo-western Pacific region based on satellite observations and the Climate Forecast System (CFS). It is found that the intensity of subseasonal air-sea coupling strongly depends on the season with most prominent interaction in the summer hemisphere. The time lag between rainfall and SST displays pronounced spatial variations and asymmetric feature. In observations, the regions of the atmosphere forcing the SST tend to shift to subtopics compared to those of the SST forcing the atmosphere. In the CFS, the regions of the atmosphere forcing the SST tend to be collocated with those of the SST forcing the atmosphere. The CFS captures reasonably well the seasonality in the intensity of air-sea coupling, but probably with an overestimation of the coupling strength. The SST response to the atmosphere takes longer time in the CFS compared to observations. Copyright 2008 by the American Geophysical Union.