气候变暖背景下西南四省市暴雨洪涝灾害风险变化

为了对西南地区气候变暖前后四省市相对灾情指数变化、暴雨洪涝相对灾情概率分布和暴雨洪涝灾害致灾因子危险性风险进行评价,采用西南地区四省市83个气象站点的逐日降水和气温资料、以及灾情数据等,首先利用突变检验确定气候变化突变年,然后借助灰色关联法、信息分配法以及熵权法等进行分析。结果表明:西南地区四省市年平均气温于1998年发生突变,总体以0.26℃/10年的速率呈显著性上升趋势;四个省市1978-2018年间的相对灾情指数主要集中在0.65~0.85之间,其中以小灾、中灾居多,变暖后较变暖前大灾发生频次增加显著;暴雨洪涝致灾因子危险性评估中指数变化主要呈西南-东北走向,两边为危险性增加区域、中间地区增幅较少或有所减小,川渝地区在变暖前后暴雨洪涝灾害危险性均高于云贵地区。

Risk Change of Rainstorm and Flood Disaster in Four Provinces and cities of Southwestern China under the Background of Climate Warming

In order to evaluate the relative disaster index changes of the four provinces and cities before and after climate warming in the southwestern region,the probability distribution of relative disaster and risk assessment of hazard factors of rainstorm and flood,based on the daily precipitation and temperature data of 83 meteorological stations of the four provinces and cities in Southwestern China,as well as disaster data,firstly,the abrupt change year of climate change is determined by mutation test,then the grey correlation method,information distribution method and entropy weight method are used for analysis.The results show that the annual average temperature in the four provinces and cities changed abruptly in 1998 and show a significant upward trend at the rate of 0.26℃·10a-1.The relative disaster index of the four provinces and cities from 1978 to 2018 was mainly concentrated in the range of 0.65-0.85,with small and medium disasters in the majority.The frequency of major disasters increased significantly after warming compared with that before warming.The change of index in risk assessment of hazard factors of rainstorm and flood was mainly from southwest to northeast.Areas with increased risk were mainly on both sides,and the growth amplitude in the middle region was less or decreased.The hazard of rainstorm and flood disaster in Sichuan and Chongqing was higher than that in Yunnan and Guizhou province before and after warming.