登陆广东的热带气旋灾害指数特征分析

Analysis of the Characteristics of Disaster Indexes for Tropical Cyclones Making Landfall in Guangdong

基于3种灾害指数(风灾害指数、雨灾害指数和风雨联合灾害指数)对比了1970—2018年登陆广东与登陆我国的热带气旋灾害指数的特征。结果表明:登陆广东的热带气旋所造成的雨灾害指数略高于我国平均值,而风灾害指数略低于我国平均值,风雨联合指数与我国平均值相当。在长期变化趋势方面,与登陆我国的热带气旋灾害指数的平均值比较,登陆广东热带气旋的平均雨灾害指数和风雨联合灾害指数均呈现更强的增加趋势。尽管登陆广东和登陆我国的热带气旋的总数量在最近时期存在减少的趋势,但是由于平均单个热带气旋引起的雨灾害指数及风雨联合灾害指数均呈现增加的趋势,从而导致相应的年累计总灾害指数并没有出现减少的趋势。登陆广东的平均单个热带气旋的雨灾害指数及风雨联合灾害指数的上升趋势均较登陆我国的单个热带气旋的平均值更强。灾害等级强的热带气旋数量的增加趋势是造成平均单个热带气旋的雨灾害指数及风雨联合灾害指数增加的重要原因。

Based on three disaster indexes(for the wind,rain and wind and rain combined),this work compares the characteristics of disaster indexes for the tropical cyclones(TCs)making landfall either in the province of Guangdong or China from 1970 to 2018.The results are shown as follows.For Guangdong-landfalling TCs,the disaster index for the rain(to be referred to as“R-index”hereafter)is slightly higher and the disaster index for the wind(to be referred to as“W-index”hereafter)is a little lower than the mean value for China respectively,and the disaster index for wind and rain combined(to be referred to as“W/R-index”hereafter)is comparable to the national mean.In the regard of long-term variation trends,the average R-index and W/R-index for the Guangdong-landfalling TCs tend to increase more than the averages for the TCs making landfall in China.Despite of a decreasing tendency in the total landfalls of TCs for both the province and the nation in recent times,annual cumulative disaster indexes do not show any trend of decreasing due to the trends of increasing R-index and W/R-index for average individual TCs.The rising trends of R-index and W/R-index for average individual TCs making landfall in Guangdong are more significant than the averages of individual TCs landing in the whole nation.The increasing trends of the number of TCs with high destructive power are important causes for the increased R-index and W/R-index for average individual TCs.