关键词: 夏季风系统, 振荡, 降水

Abstract: In this paper, the rainfall data in the late 30 years in East China is analysed.It is found that the variation trend of precipitation between North and South China is marked contrary in the early summer.The trend of North China is above normal in 50's, below normal from 60's to 70's, and with an opposite tendency in the South of Changjiang Valley.By analysing the variation of the sunner monsoon systems in East Asia, a long period of oscillation about 3 to 4 years is also obtained.The interaction between the monsoon oscillation and the variation of sea surfare temperature in east equatorial pacific produce a.feedback couple oscillation.According to the above results, a possible long range weather process model of the sea surface temperature effect on the rainfall distribution in East China through the variation of the summer monsoon systems has been proposed as follows.When the sea surface temperature in East equatorial pacific is higher that normal, the sea surface pressure in the easi equatorial Pacific is lower and the Australian anticycle is stronger, while the walker cell is weakened, the cross equatorial air currents and subtropical anticylones are also strengthened.So the summer monsoon circulation and the middle latitude westerlies in the East Asia are intensified.The precipitation is above normal in North China and below in South China.On the contrary, when the sea surface temperature in east equatorial pacific is cold, the walker cell is intensified and other monsoon systems are all weakened.Then the rainfall is below normal in North China and above normal in South China.

Key words: summer monsoon systems, oscillation precipitation