The Short-Range Fluctuations of Monsoons and their Associaton with the Major Weather Events in China

Abstract

China, as are other countries, is greatly affected by summer monsoons and their associated heavy rainfalls. A notable example for severity and duration of rainfalls is Meiyu (Plum Rains) occurring over the Yangtze River Valley. Almost every year, much damage is caused in China by flash floods or persistent floods caused by excessively heavy rains. In some years, the regional loss of property and lives reaches disaster proportions, exemplified by the extensive and devastating flood of the Huaihe River (in the central part of China) in August 1975. Much emphasis has been placed in recent years in China on research dealing with heavy rain with the aim of improving the prediction of heavy rainfall. The summer monsoon rainfalls in China mainly include the pre-summer heavy rainfall in South China, the Meiyu (Plum Rains) over the Yangtze River and Huaihe River Valleys and the mid-summer heavy rainfall in northern China. For years, Chinese meteorologists have paid more attention to these problems. In the 1950’s, the research into this aspect was focused on large-scale circulation conditions and rain-bearing synoptic systems (Xie et al., 1956; Tao et al., 1957). During the past 20 years, however, emphasis has been placed on the diagnostic analysis and theoretical study of meso- and small-scale systems.