热带对流活动异常对华南前汛期旱涝影响的诊断分析

DIAGNOSTIC ANALYSIS ON IMPACT OF CONVECTIVE ACTIVITY ANOMALIES OVER TROPIC ON FLOOD/DROUGHT DURING THE FIRST RAINY SEASON IN SOUTN CHINA

关键词:  旱涝  OLR  大气环流

Key words:  flood/drought  OLR  atmospheric circulation

摘要:

利用月平均OLR资料,分析了影响华南前汛期旱涝的前期与同期中低纬对流活动异常的分布特征,结果表明菲律宾附近海域与赤道中东太平洋对流活动的异常是影响前汛期旱涝的重要因子;前期冬季西太平洋暖池附近对流活动异常变化则是旱涝前期一个强的征兆信号,分析中还揭示了东亚太平洋中低纬Hadley环流的异常直接影响到华南前汛期旱涝。为了探讨前汛期旱涝成因,文中进一步分析了北半球大气环流动力结构对菲律宾附近海域对流活动异常的响应,提出该海域对流活动的异常可通过影响大气环流的遥相关波列而影响华南前汛期旱涝的可能途径。

Abstract:

Based on mean monthly OLR data, the characteristics distributions of convective activities over middle and low latitude are analyzed in relation to flood/drought during the first rainy season in south china. The results show that the sea near Philippines is a key area where convective activities affect the rainfall during the season, another key area is equatorial central-eastern Pacific. The OLR anomalies in last winter over the warm pool of tropical West Pacific is a strong signal in earlier stage of flood/drought. The direct impact of Hadley circulation over East Asia and Pacific on the flood/drought is revealed. In order to know the causes of flood/drought formation, some further analyses are made for the dynamic structure of atmospheric circulation of the Northern Hemisphere responding to the convective activities over the sea near Philippines, and the possible ways of the influence of East Asia and Pacific teleconnection wavetrain on flood/drought during the first rainy season in south China are also discussed.