THE EFFECTS OF THE QINGHAI-XIZANG PLATEAU ON THE MEAN SUMMER CIRCULATION OVER EAST ASIA

Four numerical experiments of simulation have been conducted in this paper by the use of a five-layer primitive equation numerical model with incorporated pressure-sigma vertical coordinate system. The initial fields are taken from the July zonal mean data of many years, while the heat sources and sinks are ideally specified according to the mean heating field over the East Asia calculated from the real data of July, 1979. On the basis of simulated results of temperature and geopotential height patterns we emphatically discuss the effects of the topography and the heating of the Qinghai-Xizang Plateau. From the analyses in this paper, it appears that the heating over the Bengal region makes a larger contribution to the middle and the south branches of the monsoon cell and is also the main cause for the existence of the southerly channel to the east of the Plateau, for the break of the subtropical anticyclone belt below the 500 hPa level and for the formation of the summer Asian anticyclone at the 300 hPa level, while the heating over the Plateau makes a larger contribution to the Plateau monsoon cell and to the anticyclone at the 100 hPa.