Understanding the regional hydrological response to varying CO2 concentration is critical for cost-benefit analysis of mitigation and adaptation polices in the near future.To characterize summer monsoon rainfall change in East Asia in a changing CO2 pathway,we used the Community Earth System Model (CESM) with 28 ensemble members in which the CO2 concentration increases at a rate of 1％ per year until its quadru-pling peak,i.e.,1468 ppm (ramp-up period),followed by a decrease of 1％ per year until the present-day climate conditions,i.e.,367 ppm (ramp-down period).Although the CO2 concentration change is sym-metric in time,the amount of summer rainfall anomaly in East Asia is increased 42％ during a ramp-down period than that during a ramp-up period when the two periods of the same CO2 concentration are compared.This asymmetrical rainfall response is mainly due to an enhanced El Ni(n)o-like warming pattern as well as its associated increase in the sea surface temperature in the western North Pacific dur-ing a ramp-down period.These sea surface temperature patterns enhance the atmospheric teleconnec-tions and the local meridional circulations around East Asia,resulting in more rainfall over East Asia during a ramp-down period.This result implies that the removal of CO2 does not guarantee the return of regional rainfall to the previous climate state with the same CO2 concentration.

Se-Yong Song;Sang-Wook Yeh;Soon-Il An;Jong-Seong Kug;Seung-Ki Min;Seok-Woo Son;Jongsoo Shin

Department of Marine Sciences and Convergence Technology,Hanyang University,Ansan 15588,South Korea;Department of Atmospheric Sciences/Irreversible Climate Change Research Center,Yonsei University,Seoul 03722,South Korea;Division of Environmental Science and Engineering,Pohang University of Science and Technology,Pohang 37673,South Korea;Institute for Convergence Research and Education in Advanced Technology,Yonsei University,Incheon 21983,South Korea;School of Earth and Environmental Science,Seoul National University,Seoul 08826,South Korea

科学通报（英文版）

[1]Se-Yong Song;Sang-Wook Yeh;Soon-Il An;Jong-Seong Kug;Seung-Ki Min;Seok-Woo Son;Jongsoo Shin-.Asymmetrical response of summer rainfall in East Asia to CO2 forcing)[J].科学通报（英文版）,2022(02):213-222

polices,quadru,teleconnec

Asymmetrical,response,summer,rainfall,East,Asia,forcing,Understanding,regional,hydrological,varying,concentration,critical,cost,benefit,analysis,mitigation,adaptation,near,future,To,characterize,monsoon,change,changing,pathway,used,Community,Earth,System,Model,CESM,ensemble,members,which,increases,rate,year,until,its,pling,peak,ppm,ramp,up,followed,by,decrease,present,day,climate,conditions,down,Although,amount,anomaly,increased,during,than,that,when,two,periods,same,compared,This,asymmetrical,mainly,due,enhanced,El,like,warming,well,associated,sea,surface,temperature,western,North,Pacific,These,patterns,atmospheric,local,meridional,circulations,around,resulting,more,over,implies,removal,does,not,guarantee,return,previous,state

0.489994