登陆中国的热带气旋活动及其风雨变化的RegCM4集合预估

Projected changes in activity and impact of associated wind and rainfall of the tropical cyclones landing in China based on RegCM4 downscaling simulations

登陆热带气旋通过带来狂风、暴雨,给中国沿海地区的人民生活和经济财产造成巨大影响,合理预估全球变暖背景下登陆中国热带气旋的风雨影响,可为中国沿海地区的防灾、减灾工作提供科学指导。文中基于5个CMIP5全球气候模式驱动的区域气候模式RegCM4对当代和两种情景下21世纪末期的动力降尺度模拟结果,评估了区域气候模式对当代登陆中国的热带气旋强度、路径、风雨影响的模拟能力,在此基础上,对该热带气旋特征的未来变化进行了预估。结果表明:区域气候模式可以合理再现观测中登陆中国的热带气旋主要特征,但存在一定的偏差。未来在RCP4.5和RCP8.5情景下,登陆辽宁、山东、江苏、广东、广西、海南和整个中国的热带气旋数量都将增多,其中辽宁、山东和江苏的增幅较大。相比当代,未来情景下登陆中国后的热带气旋强度和大风影响将增强。登陆热带气旋的路径频率有向北移动的倾向,热带气旋导致的平均降水强度在大部分地区将加强,在山东半岛及其附近海域将减少。总体上,在全球变暖背景下,21世纪末期将有更强、更多的热带气旋登陆中国,且其带来的风雨影响也将加强。

Life and economy development in coastal areas of China are severely impacted by strong winds and heavy rains caused by landfall tropical cyclones(TCs).In the context of global warming,the prediction of future changes in wind and rainfall associated with TCs is highly useful for disaster prevention and mitigation in coastal areas of China.Based on a set of dynamical downscaling simulations using the regional climate model RegCM4 driven by outputs of five Coupled Model Intercomparison Project Phase 5(CMIP5)global climate models over East Asia,the intensities,tracks,winds and rainfalls of TCs landing in China in the present-day period(1986—2005)are firstly evaluated,and changes in these characteristics at the end of the 21 century(2079—2098)under RCP4.5 and RCP8.5 scenarios are then analyzed.Results show that the RegCM4 can reproduce the main features of the observed landfall TCs during 1986—2005,although with some biases.Under RCP4.5 and RCP8.5 scenarios,the numbers of TCs landing in Liaoning province,Shandong province,Jiangsu province,Guangdong province,Guangxi Zhuang autonomous region,Hainan province and the whole China region will increase,with large increases in Liaoning province,Shandong province and Jiangsu province.Compared to that in the present-day,the intensity of TCs after landing in China and the impact of strong winds will increase.In addition,the tracks of landfall TCs tend to move northward,and the rainfall intensity will be stronger in most areas,except those over Shandong Peninsula and its adjacent waters.Overall,stronger and more TCs will land in China in the future.Meanwhile,the wind and rainfall associated with landfall TCs will enhance.