1965-2010年7-9月影响中国的热带气旋降水变化趋势分析

利用中国气象局逐日台站降水和上海台风研究所最佳台风路径等资料,对1965—2010年夏季(7—9月)影响中国热带气旋降水的变化趋势及影响机制进行了分析。热带气旋降水主要影响中国东部和南部,夏季平均的热带气旋降水由沿海向内陆,由东南向西北递减。自1965年以来,夏季影响中国的热带气旋降水呈现华东及东南沿海增多,华南沿海、海南岛以及西南地区减少的变化趋势。分析发现,一方面夏季西北太平洋副热带高压加强西伸,导致同期中国东部地区上空水汽辐合增强;另一方面热带气旋的引导气流发生变化,使夏季热带气旋盛行路径由南海向东亚沿岸偏移,这两个因子的共同作用致使影响中国的热带气旋降水发生变化。

Analysis of tropical cyclone precipitation changes in China in ,July September during 1965-2010

The trend of the summer (July-September) tropical cyclone precipitation in China during 1965-2010 and the assodated mechanisms are examined in this study with the daily station precipitation and tropical cyclone track datasets. The results show that,in China, the summer tropical cyclone rainfall gradually decreases from the southeast coastal regions to the northwest regions. An increasing trend in the tropical cyclone precipitation is found in East China and the southeast coastal areas, with a decreasing trend in South China coastal areas, Hainan Province and southwestern China over the period 1965-2010.The strengthening and westward extension of the summer western North Pacific subtropical high result in strong moisture convcrgenee in East China, and the change of large-scale steering flows causes the shift in summer prevailing typhoon tracks from the South China Sca to East Asian coast, leading to changes in the summer tropical cyclone precipitation in China since 1965.