Responses of the East Asian summer monsoon to aerosol forcing in CMIP5 models: The role of upper-tropospheric temperature change
Responses of the East Asian summer monsoon to aerosol forcing in CMIP5 models: The role of upper-tropospheric temperature change
复制标题
CMIP5模型中东亚夏季风对气溶胶强迫的响应：对流层上层温度变化的作用
DOI：
10.1002/joc.6887
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Wang Zhili
中科院分区：
文献类型：
--
作者：
Mu Junyu;Wang Zhili
We quantitatively distinguish the fast and slow responses of the East Asian summer monsoon (EASM) to aerosol forcing using the outputs from 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models. The mechanism of the EASM change due to aerosol forcing is then evaluated from the perspective of upper‐tropospheric temperature change. The results show that aerosol forcing leads to the weakening of the EASM circulation and decreases in precipitation. The aerosol‐induced fast atmospheric response dominates the weakening of EASM and the decreased precipitation over the eastern China. In the fast response, upper‐tropospheric cooling in the mid‐latitudes of East Asia during summer changes the circulation structure, thereby causing the weakening of the EASM. The formation of upper‐tropospheric cooling is closely related to the eastward propagation of atmospheric cooling caused by aerosol forcing in Europe and the resulting change in local meridional heat transport. The slow ocean‐mediated response to aerosol forcing partially offsets the weakening of the EASM over the eastern China in the fast response. In the slow response, southwesterly wind is enhanced and precipitation is increased over the eastern China, while southwesterly wind is weakened over the northwestern Pacific and the South China Sea, which dominates the decrease in precipitation over the oceans. The aerosol‐induced changes of land–sea thermal contrasts further confirm that the decrease of upper‐tropospheric land–sea thermal contrasts over East Asia in the fast response plays a key role in driving the weakening of the EASM.
