Influence of Different Development Periods of the Strong and Weak South Asian Monsoon on the Vertical Circulation over the Qinghai-Xizang （Tibetan） Plateau

In order to explore the role of the changes in the strength and weakness of the South Asian monsoon on the vertical circulation of the Qinghai-Xizang （Tibetan） Plateau， the South Asian monsoon index WYI was calculated using the high-resolution JRA55 reanalysis data for the past 30 years from 1990 to 2019 and the strong and weak years of the South Asian monsoon were selected， and the effects of the changes in the strength and weakness of the South Asian monsoon on the vertical circulation of the Qinghai-Xizang （Tibetan） Plateau were analyzed by comparing the three different periods of the pre-monsoon outbreak， outbreak period and late outbreak.The following main conclusions were obtained： （1） The strength and extent of updrafts on the southern side of the plateau in May in WYI strong years are greater than in weak years， the intensity of updrafts on the main and southern sides of the plateau increases in July， and the difference between strong and weak years is not obvious.（2） In May and October， both mass and