Asymmetrical response of summer rainfall in East Asia to CO_(2)forcing  

东亚夏季降水对CO_(2)强迫的非对称响应

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

机构地区：[1]Department of Marine Sciences and Convergence Technology,Hanyang University,Ansan 15588,South Korea [2]Department of Atmospheric Sciences/Irreversible Climate Change Research Center,Yonsei University,Seoul 03722,South Korea [3]Division of Environmental Science and Engineering,Pohang University of Science and Technology,Pohang 37673,South Korea [4]Institute for Convergence Research and Education in Advanced Technology,Yonsei University,Incheon 21983,South Korea [5]School of Earth and Environmental Science,Seoul National University,Seoul 08826,South Korea

出　　处：《Science Bulletin》2022年第2期213-222,M0004,共11页科学通报（英文版）

基　　金：supported by the National Research Foundation of Korea(NRF) grant(NRF-2018R1A5A1024958)。

摘　　要：Understanding the regional hydrological response to varying CO_(2)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 CO_(2)pathway, we used the Community Earth System Model(CESM) with28 ensemble members in which the CO_(2)concentration increases at a rate of 1% per year until its quadrupling 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 CO_(2)concentration change is symmetric in time, the amount of summer rainfall anomaly in East Asia is increased 42% during a rampdown period than that during a ramp-up period when the two periods of the same CO_(2)concentration are compared. This asymmetrical rainfall response is mainly due to an enhanced El Ni?o-like warming pattern as well as its associated increase in the sea surface temperature in the western North Pacific during a ramp-down period. These sea surface temperature patterns enhance the atmospheric teleconnections 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 CO_(2)does not guarantee the return of regional rainfall to the previous climate state with the same CO_(2)concentration.理解不同CO_(2)浓度下的区域水文响应,对于缓解和适应政策的成本收益分析至关重要.为了描述东亚地区夏季季风降水在不同的CO_(2)路径中的变化,我们使用了通用地球系统模式(CESM)的28个集合样本,使CO_(2)浓度以每年1%的速度增长,直到其四倍峰值,即1468 ppm(上升期),然后每年下降1%,直至当前的气候状况,即367 ppm(下降期).尽管CO_(2)浓度的变化在时间上是对称的,但当比较相同CO_(2)浓度的两个时期时,东亚夏季降水异常量在下降期比上升期增加了42%.这种不对称的降雨响应主要是由于在下降期类似厄尔尼诺的升温型的增强,以及与之相关的西北太平洋海表温度的升高.这些海表温度型增强了东亚周边的大气遥相关和局地经向环流,导致东亚地区降雨在下降期增加.这一结果表明,去除CO_(2)并不能保证区域降雨可恢复到同等CO_(2)浓度下以前的气候状态.

关 键 词：CO_(2)concentration East Asian summer monsoon Asymmetric rainfall El Ni?o-like warming 

分 类 号：X16[环境科学与工程—环境科学] P333[天文地球—水文科学]