The Seasonal Change of the Wind Field in Southern Asia During the Onset of Summer Monsoon

By using the wind data in summer months for 1973—1979, the seasonal change of the wind field in Southern Asia during the onset of summer monsoon is studied. It is found that during the onset the main components of Asian summer monsoon system show a marked change. The changes in the Indian monsoon region are more marked than that in the Eastern Asian monsoon region. We also found that in the huge Southern Asian monsoon system there are two sub-system one is the Indian monsoon system, and the other is the Eastern Asian monsoon system. The components in the Eastern Asian monsoon system are: Austrian anticyclone, low-level cross-equatorial flow at 105oE, monsoon trough in the South China Sea, subtropical high pressure ridge in the West Pacific and the Mei-Yu front in the Yangtze River Valley