西北太平洋和南海热带气旋的气候特征分析

Climatic Characteristics of Tropical Cyclones over Northwestern Pacific and South China Sea

对1949—2005年共57年西北太平洋上和南海中心风速≥8级的热带气旋活动的若干特征进行了统计学分析,结果表明:57年在西北太平洋和南海热带气旋年平均发生频数为27.47个,登陆我国年平均数6.89个,近10年发生和登陆频数处于57年的低值区;7—9月是发生和登陆我国最多的月份,华南沿海是登陆最频繁的区域。我国东北地区、华北、黄淮、江淮、江南、华南和西南地区东部均可出现TC暴雨,高频区在东南沿海地区,中心在海南和广东东部沿海,次频中心位于广西沿海和福建东南部沿海。此分析可为登陆热带气旋的暴雨预报提供气候背景。

Tropical cyclones （TCs） over the Northwestern Pacific and South China Sea, of which wind velocity exceeds grade 8, are statistically investigated for the period of 1949-2005. Results show that 27.47 TCs occur annually over those regions, with 6.89 TCs landing over China. Both of the numbers in recent 10 years are below the mean of 1949-2005. The most preferable time period for the generation and landing of TC over China is July to September. The South Coast of China is the location of most landing TC（s）. Most coast regions of China, such as Northeast China, North China, Yellow River- Huaihe River basins, south to the Yangtze River, South China and the eastern Southwest China and so on, have the chance for heavy rainfall of typhoon. Southeast coast of China is featured by the highest possibility of TC heavy rainfall. The maximum is found over Hainan Province and the east coast of Guangdong Province, the second over the coast of Guangxi Province and southeast coast of Fujian Province. The spatial pattern of frequency in TC heavy rainfall provides the background information for the forecast of landing TC rainfall.