THE INTERANNUAL OSCILLATION OF RAINFALL OVER CHINA AND ITS RELATION TO THE INTERANNUAL OSCILLATION OF THE AIR-SEA SYSTEM*

The quasi-biennial oscillation(QBO) and 3.5 years quasi-periodic oscillation(named TO hereafter) are exhibited in most of 48 weather stations of China by applying power spectrum analysis to the monthly rainfall data for the period from Jan. 1933 to Dec. 1987. In order to reveal the features of QBO and TO components, another rainfall data set in 160 stations over China for the period from Jan. 1951 to Dec. 1987 was analysed by means of a new method named complex empirical orthogonal function(CEOF). The results show that both QBO and TO modes exhibit two propagation ways:one originates in Northeast China, extends southward, passes through North China and reaches the eastern part of Northwest China and the northern part of Southwest China; the other appears over Guangdong and Fujian, then moves northward and westward respectively to the Huanghe-Huaihe Basin and Southwest China.These two paths of oscillation meet over North China and the area between the Changjiang River and the Huanghe River. A significant correlation exists between the interannual oscillation of the rainfall over China and that of the sea surface temperature(SST) at the equator. Although the correlation between the rainfall over China and the SST over the equatorial eastern Pacific is rather weak, the correlation between their oscillation component is pronounced.