南海中北部热带气旋强度突变的天气气候特征分析

Analysis on climatic characteristics of tropical cyclone's intensity catastrophe in Northern South China Sea

本文对1960-2002年在南海中北部活动的热带气旋进行分析统计,发现有如下气候特征:南海中北部平均每年有6.7个热带气旋,有4.9个热带气旋强度发生突变,其中有3%的热带气旋只发生突然增强,72%的热带气旋只发生突然减弱,25%的热带气旋既发生突然增强又发生突然减弱过程.强度突然减弱发生在4-12月,主要集中在登陆和登陆后的陆地区域,分布较广;强度突然增强发生在4-11月,主要出现在珠江口以西至海南岛东部海面、东沙群岛和西沙群岛海面.

With statistical analysis on the tropical cyclone （TC） in Northern South China Sea from 1960 to 2002 , It was found that there were 6. 7 TCs and 4. 9 TCs of intensity catastrophe Occurred annually . Among them only about 3% ,of intensity catastrophe strengthened rapid, about 72% of the total decreased rapidly and less then 25% strengthened rapidly before they diminished. TC intensity which decreased rapidly often occurred on broad areas after landing from April to December. TC intensity which strengthened rapidly mainly occurred on the sea from the west of Zhujiang Estuary to the east of Hainan, Dongsha and Xisha Islands from April to November.