Interannual Variation of Summer Subtropical Westerly Jet in East Asia and Its Impacts on the Climate Anomalies of East Asia Summer Monsoon

Abstract

Abstract The interannual variability of the subtropical westerly jet over East Asian (EAJS), its impacts on the climate anomalies of East Asian Summer Monsoon, and their possible mechanisms are investigated in this paper. The impacts of south‐north alternation of EAJS concentrate in the Asia‐Australian Monsoon region and the two sides of the climatological positions of EAJS, which is quite different with the atmospheric response to SO (South Oscillation) or ENSO (El Nino‐South Oscillation). The impacts of ENSO concentrate in the middle and east part of the tropical‐extratropical Pacific. There exist two dominant modes of the summer westerly jet in the north hemisphere. The first mode deals with the south‐north alternation of the westerly jet in the Asia‐Pacific area, esp. in the East Asia. The second mode appears in the mid‐east Pacific of 150°E~20°W. The two modes link with two significantly different SST patterns in the Pacific, but they can all influence the intensity of 200 hPa South Asian Anticyclone, esp. the intensity of east part of the South Asian Anticyclone, and which will contribute to the formation of summer floods and droughts in the east part of China.