Variation trend of typhoon activity influencing China during the past 20 years
Previous studies indicated that Tropical Cyclone (TC) intensity,frequency,locations of genesis and prevailing tracks over the western North Pacific might change under the background of global warming.Since TCs are one of the major natural disasters in China,the changes of TC activity may lead to significant loss of life and damage.In this study,the newly defined TC activity index Cyclone Activity Index (CAI) is used to examine the variations of TC influencing China's coastal regions and its possible mechanisms.Results show that although no significant trend was seen in the landfall typhoon frequency over the past 50 years,a remarkable reduction was revealed in the frequency of typhoons affecting China after 1996.It is suggested that the southern (southeastern) coastal areas suffer from less (more) TC effects.The value of CAI increases in Xiamen,Fuzhou,Wenzhou,Hangzhou and Shanghai in summer (June-October) (the former three cities are significant at the 95％ confidence level,while the latter two are significant at the 90％ confidence test),on the contrary,a significant decreasing of CAI was presented in Sanya and Haikou (significant at the 95％ confidence test).Further analysis indicates that these variations are closely associated with the changes in the TC prevailing tracks and intensity.
国家科技期刊平台
NSTL
万方数据
维普
