Subtropical high anomalies over the western Pacific and its relations to the Asian monsoon and SST anomaly

Using the data of 500 hPa geopotential height from 1951 to 1995, SST roughl y in the same period and OLR data from 1974 to 1994, the relation between t he anomalies of subtropical high (STH for short) and the tropical circulati ons including the Asian monsoon as well as the convective activity are stud ied. In order to study the physical process of the air-sea interaction rela ted to STH anomaly, the correlation of STH with SST at various sea areas, l agged and simultaneous, has been calculated. Comparing the difference of OLR, wind fields, vertical circulations and SST anomalies in the strong and weak STH, we investigate the characteristics o f global circulations and the SST distributions related to the anomalous ST H at the western Pacific both in winter and summer. Much attention has been paid to the study of the air-sea interaction and the relationship between the East Asian monsoon and the STH in the western Pacific. A special vertic al circulation, related to the STH anomalies is found, which connects the m onsoon current to the west and the vertical flow influenced by the SST anom aly in the tropical eastern Pacific.