利用区域气候模式预估未来登陆中国热带气旋活动

鉴于热带气旋（TC）对我国沿海地区的影响，研究全球变暖背景下未来登陆我国TC活动的变化，对于我国沿海地区的防灾减灾具有重要意义。基于CMIP5中全球气候模式HadGEM2-ES数据，文中利用区域气候模式RegCM4开展了历史时期和3种情景（RCP2.6、RCP4.5和RCP8.5）下未来东亚区域气候的动力降尺度模拟，检验了模式对历史登陆我国TC活动及其相关大尺度环境场的模拟能力，并预估了3种情景下2030—2039年、2050—2059年和2089—2098年，登陆我国TC的路径、强度和频率的变化特征。结果表明：模式能合理地再现东亚区域历史时期（1986—2005年）大气环流场的空间结构以及登陆我国TC的特征；在3种情景下未来登陆我国TC的平均强度和数量均有不同程度的增加，尤其是台风及以上级别TC的总数明显增加，其中RCP8.5情景最突出，到21世纪末期（2089—2098年）登陆我国TC的平均强度、台风及以上级别TC总数的年平均值较历史时期将分别增加7.56%和1.05个；不同情景下未来登陆我国TC的路径均有不同程度的北移趋势，且全球升温的幅度越大，北移趋势越明显，这可能与未来中国近海显著变暖和垂直风切变减弱有关。未来我国沿海地区尤其是中高纬度很可能将面临日益严峻的TC灾害风险，亟需尽快开展防灾减灾及对策研究。

Projection of the tropical cyclones landing in China in the future based on regional climate model

In view of the impact of tropical cyclones (TCs) on coastal areas of China, it is of great significance for disaster prevention and reduction to study the changes of TC activities landing in China in the future under global warming. Based on outputs from the global climate model HadGEM2-ES in CMIP5, this study carried out dynamic downscaling simulation of the regional climate over East Asia in historical period and in the future under three representative concentration pathways (RCPs) with low, intermediate and very high greenhouse gas emissions (RCP2.6, RCP4.5 and RCP8.5), and tested the model’s ability of simulating the activities of TCs landing in China and TC-related large-scale environmental fields by using the regional climate model RegCM4. The changes of track, intensity and frequency of TCs landing in China during 2030-2039, 2050-2059 and 2089-2098 under three RCPs were also projected. The results are as follows. The model can reasonably reproduce the spatial structure of large-scale atmospheric circulation field over East Asia and the characteristics of TCs landing in China in the historical period (1986-2005). The average intensity and number of TCs landing in China under three RCPs will increase in varying degrees in the future, especially the number of typhoons and above will increase significantly. The most prominent changes appear in the RCP8.5 scenario, by the end of the 21st century (2089-2098), the average intensity, annual mean number of typhoons and above will increase by 7.56% and 1.05, respectively. The tracks of TCs landing in China under three RCPs in the future are prone to move northward in varying degrees. Moreover, the greater the global warming, the more obvious the northward tendency, which may be related to the significant warming offshore China and the weakening of vertical wind shear in the future. The prediction results of this study show that coastal areas of China, especially in the middle and high latitudes, are likely to face increasingly severe TC disasters in the future, so it is necessary to find the countermeasures of disaster prevention and reduction as soon as possible.