Interannual and Interdecadal Variations of the East Asian Summer Monsoon and Tropical Pacific SSTs. Part II: Meridional Structure of the Monsoon

Abstract

The relationship between the interannual variations of the East Asian summer monsoon and that of the tropical SST shows considerable variations. In this study, rainfall in the southeastern coastal area of China (SEC) during 1951–96 is used to composite the tropical SST, 850-hPa wind, and 500-hPa height. The results relative to the May–June rainfall, which represents most of the SEC summer monsoon rainfall, are compared to the Yangtze River Valley (YRV) rainfall composites. It is shown that strong interdecadal changes in the Pacific may account for the observed variations in the meridional structure of the monsoon–SST relationship. The western Pacific 500-hPa subtropical ridge, which is influenced by the equatorial eastern Pacific SST, is crucial to these variations.