全球升温1.5℃与2.0℃情景下中国东南沿海致灾气旋的时空变化

SPATIOTEMPORAL DISTRIBUTIONS OF HAZARD-INDUCING TROPICAL CYCLONES UNDER THE 1.5℃ AND 2.0℃ GLOBAL WARMING SCENARIOS IN SOUTHEAST COASTAL CHINA

将造成经济损失的热带气旋定义为致灾气旋。基于气象观测站的逐日气压、风速和降水量数据确定致灾气旋阈值,结合区域气候模式COSMO-CLM(CCLM)在1961—2100年的输出资料,预估致灾气旋发生频数及其风速与降水量,分析全球升温1.5℃与2.0℃情景下,中国东南沿海地区致灾气旋时空变化特征。结果表明:(1) 1986—2015年,东南沿海地区致灾气旋发生频数共计180个,整体呈上升趋势,平均风速和降水量分别为8.7 m/s和129.8 mm,对浙江东部及广东东部沿海影响最严重。(2)全球升温1.5℃,2020—2039年致灾气旋频数将由基准期(1986—2005年)的111个上升至138个,增加区域主要位于广东省西南地区及福建省南部地区;平均风速和降水量分别上升15%和17%,至8.4 m/s和109.9 mm,以福建省沿海地区增加最明显。(3)全球升温2.0℃,2040—2059年致灾气旋频数较1986—2005年增加33%,将达148个;风速上升32%,以浙江省东部、福建和广东省接壤的沿海地区及广东省南部增幅最大;降水量上升35%,以福建与广东省接壤的沿海地区及广东省西南地区增加明显。(4)相比升温1.5℃,全球气温额外升高0.5℃,东南沿海地区致灾气旋频数及其风速与降水量将分别上升9%、17%和18%。努力将温升控制在1.5℃,对降低致灾气旋频率和强度增加所导致的影响具有重要意义。

Based on the data of tropical cyclones(TCs)in China for 1986-2015,TCs that caused economic losses are defined as hazard-inducing TCs.The threshold of hazard-inducing TCs in southeastern coastal China is determined through observed daily air pressure,wind speed and precipitation data from meteorological stations.Subsequently,the frequency,wind speed and precipitation of hazard-inducing TCs are predicted by the regional climate model COSMO-CLM(CCLM),and their spatiotemporal variations are analyzed under the 1.5℃and 2.0℃warming scenarios relative to the baseline period of 1986-2005.Research results are shown as follows:(1)The frequency of hazard-inducing TCs in southeast coastal China shows an increasing trend from 1986 to 2005.Observed average wind speed and precipitation are 8.7 m/s and 129.8 mm,respectively.The influenced areas are mainly distributed in the east of Zhejiang province and the east coast of Guangdong province.(2)Under the 1.5℃warming scenario of 2020-2039,the frequency of hazard-inducing TCs will increase by 24%relative to 1986-2005,and the increase is mainly distributed in the southwest part of Guangdong and the southern part of Fujian.Meanwhile,wind speed and precipitation by TCs will increase by 15%and 17%,respectivley,which is most significant in the coastal areas of Fujian.(3)Under the 2.0℃warming scenario of 2040-2059,the frequency of hazard-inducing TCs will increase by 33%relative to the reference period of 1986-2005,and wind speed will increase by 32%.Precipitation will increase by 35%,with the neighboring area of coastal Fujian and Guangdong and the southwest Guangdong having the largest growth rate.(4)With the global temperature increase from 1.5℃to 2.0℃,the frequency of hazard-inducing TCs will continue to rise,and the accompanying wind speed and precipitation might also increase by 17%and 18%,respectively.The aforementioned findings revealed that the frequency,wind speed,precipitation and influential area of hazard-inducing TCs in the southeastern coast of China will increase with the rising of temperature.It is significant to control global temperature increase below 1.5℃for reducing the adverse effects of hazard-inducing TCs.