登陆中国不同强度热带气旋的变化特征

根据《热带气旋等级》国家标准(2006)，将热带气旋(TC)划分为热带低压(TD)、热带风暴(TS)、强热带风暴(STS)、台风(TY)、强台风(STY)、超强台风(SSTY)6个等级，利用中国气象局整编的1949—2006年共58年的《台风年鉴》和《热带气旋年鉴》资料，分析了登陆中国大陆、海南和台湾不同强度TC变化特征。结果表明：(1) 不同强度登陆TC频数存在年际和年代际变化，在长期趋势上，TD、TS登陆频数呈现显著的线性递减趋势，STY登陆频数呈现显著增加趋势。(2) 登陆TD、TS、STS存在6—8年的周期变化，TY具有准16年的周期变化。(3) 登陆TD、TS主要生成于南海东北部海面，登陆TY、STY、SSTY多生成于巴士海峡东南部海面和菲律宾以东洋面。(4) 在年代际变化上，南海生成的登陆TD、TS频数有减少趋势，TY、STY有增多趋势。

VARIATIONAL CHARACTERISTICS OF TROPICAL CYCLONES MAKING LANDFALL IN CHINA WITH DIFFERENT INTENSITY

According to the national standard (2006) on tropical cyclone intensity, six intensity categories are divided.That is tropical depression (TD), tropical storm (TS), strong tropical storm (STS), typhoon (TY), strong typhoon (STY), super strong typhoon (SSTY) respectively.A 58-year dataset during 1949-2006 from Yearbook of China Meteorological Administration was used to study the variational characteristics of tropical cyclones (TCs) making landfall in the Chinese mainland, Hainan and Taiwan Islands.Main results are as follows: (1) There exist interannual or interdecadal variations of the number of landfalling tropical cyclones with different intensity.As far as the long-term trend is concerned, the frequency of TD and TS shows a significantly linear trend of decrease, while the frequency of STY shows a significantly linear trend of increase.(2) There are well-defined periods of 6～8 years in the variations of annual TD, TS and STS landfall frequency and quasi-16-year periods in the variation of annual TY landfall frequency.(3) TD and TS are generated mostly over the South China Sea and TY, STY and SSTY are mostly over waters southeast of the Bashi Channel and the ocean to the east of the Philippines.(4) As far as the interdecadal trend is concerned, the frequency of landfalling TD and TS generated over the South China Sea shows a significantly linear trend of decrease.However, TY and STY show significantly linear trends of increase.