A NUMERICAL STUDY ON THE EFFECTS OF THE QINGHAIXIZANG PLATEAU ON THE MEDIUM-RANGE WEATHER PROCESSES OF THE SUMMER MONSOON RAIN IN EAST ASIA

By employing the T42L9 spectral model introduced from ECMWF and utilizing the FGGE-Ⅲb datacovering the period from 14 June to 19 June 1979,the effects of the Qinghai-Xizang Plateau on the mediumrange weather processes of the rain during the onset period of the summer monsoon in Eastern Asia in 1979 were studied numerically.According to the initial field of 12GMT 14 June 1979,five-day numerical experiments with or without the orographic effects were carried out respectively.The results show that the Plateau can influence the precipitation significantly during the summer monsoon season.Although the summer monsoon is the result of the seasonal variations of the global circulation and the heating difference between land and sea,it is influenced evidently by the Plateau in medium-range processes.There are very complex interactions between the mountain and diabatic heating effects so that both of them should be considered correctly in the general circulation models in order to describe the nature of the atmosphere reliably.