DECADE CLIMATE CHARACTERS AND FORMATION CONDITION OF FLOODING IN SOUTH AND DROUGHT IN NORTH IN CHINA

According to the analysis of the decade and interannual climate character variation of summer precipitation in recent fifty years and decade climate variation of continental high over Asia and ENSO event, the distribution of summer precipitation in recent years is contrasted. The result indicates that the distribution of summer precipitation had great change from the latter of the 1990s. The changeable distribution trends of flooding and drought in summer in the 1990s and the beginning of this century are analyzed. It is found that the decade climate character of summer precipitation had obvious change in recent years in our country. The main rain belt of the 1990s was in the Yangtze River to the north of Jiangnan areas. The decade climate character was that the precipitation was more than normal in the north and the south of China and less than normal in the middle areas. From the beginning of the end of last century, the main rain belt was located the south of the Yangtze River to South China, and the North probably entered into dry spell. It may come into the decade climate period of flooding in the south and drought in the north in summer. According the analysis, the climate character of precipitation change in recent summers related to the main rain belt moving trend from north to south, and it also related to the influence of the climate change of atmospheric circulation, especially East Asia continental high. The warm water of the equator Pacific also took the corresponding effect to decade climate change of summer precipitation. It is concluded that the summer precipitation will still has the climate character that the precipitation is more than normal in south and less in north, therefore the drought climate trend of the north will be more rigorous. It is highly important to predict the decade climate variation and short-term climate variation of summer precipitation.