多区域模式集合的东亚陆地区域的平均和极端降水未来预估

Mean and extreme precipitation projection over land area of East Asia based on multiple regional climate models

利用东亚区域联合降尺度计划(CORDEX-EA)15个区域模式的模拟结果,集合预估了高排放情景RCP8.5下东亚陆地区域平均和极端降水的未来时空变化,并量化未来预估的不确定性.结果表明:区域模式基本上能够再现东亚及各个区域平均和极端降水的多年平均分布.未来多模式集合预估的平均和极端强降水在东亚各区域多表现为增加,连续无降水日数(CDD)表现为南增北减,且变幅多随时间增大.到21世纪末期,冬季和年平均降水的增幅大值都位于中国西部(WC),冬季降水的变化在WC、蒙古(MG)、中国东北(NE)和中国华北及西北地区东部(NC)的确定性都较高,年降水的变化仅在WC和MG确定性较高.夏季降水增幅大值位于朝鲜半岛和日本(KJ),且仅在这一区域确定性较高.最大5日降水量(Rx5day)和大雨日数(R20)以增加为主且变化的空间分布较为均匀,除去中国江南及华南(SC)和KJ的R20变化,其余区域两个变量的变化确定性都较高.CDD的增幅和减幅大值分别位于SC和MG,其变化在MG、NE和SC确定性较高.

Using the simulation results from the 15 regional climate models under the framework of the CORDEX-EA(Coordinated Regional Climate Downscaling Experiment-East Asia)program,the future changes of mean and extreme precipitation over land area of East Asia under the high emission pathway of RCP8.5 are projected,and the uncertainties are also estimated quantitatively.The results show that the regional models can reasonably reproduce the spatial patterns of the mean state of mean and extreme precipitation over East Asia and its six subregions.Based on the ensemble mean,the mean precipitation and extreme heavy precipitation will increase over most regions of East Asia,and the consecutive dry days(CDD)will increase in the south but decrease in the north.Most of these changes will increase with time.By the end of the 21st century,the increase in both winter and annual precipitation will occur over western China(WC).The uncertainties on changes in winter precipitation over WC,Mongolia(MG),northeastern China(NE),and northern China(NC)are small.The low uncertainties on change in annual precipitation occur only over WC and MG.The maximum increase in summer precipitation is located in the Korean Peninsula and Japan(KJ),which are the only two subregions with low uncertainties.The spatial distributions of the increases in maximum 5-day precipitation(Rx5day)and heavy rain days(R20)are quite uniform.Except for the changes in R20 over southern China(SC)and KJ,the changes in both Rx5day and R20 over other subregions are highly robust.The maximum increase and decrease values of CDD are located in SC and MG,respectively,and the uncertainties are quite low in MG,NE,and SC.