Asian summer monsoon responses to the change of land‒sea thermodynamic contrast in a warming climate: CMIP6 projections

• Published in: Advances in climate change research Vol. 13; no. 2; pp. 205 - 217
• Main Authors: Wu, Qing-Yuan, Li, Qing-Quan, Ding, Yi-Hui, Shen, Xin-Yong, Zhao, Meng-Chu, Zhu, Yu-Xiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2022; Laboratory for Climate Studies,National Climate Centre,China Meteorological Administration,Beijing 100081,China%Laboratory for Climate Studies,National Climate Centre,China Meteorological Administration,Beijing 100081,China%Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory on Climate and Environment Change,Nanjing University of Information Science&Technology,Nanjing 210044,China; Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory on Climate and Environment Change,Nanjing University of Information Science&Technology,Nanjing 210044,China; Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,China%Training Centre,China Meteorological Administration,Beijing 100081,China; KeAi Communications Co., Ltd
• Subjects: CMIP6 projection; East Asian summer monsoon; Global warming; Land‒sea thermodynamic contrast; South Asian summer monsoon; Land‒sea thermodynamic contrast; South Asian summer monsoon; Global warming; CMIP6 projection; East Asian summer monsoon; Land-sea thermodynamic contrast
• ISSN: 1674-9278; 1674-9278
• DOI: 10.1016/j.accre.2022.01.001

It is of practical significance to use the updated Coupled Model Intercomparison Project Phase 6 (CMIP6) models to study the impact of changes in land‒sea thermodynamic contrast (TC) on the Asian summer monsoon under different scenarios and to compare the similarities and differences of the impact mechanisms between different monsoon regions. In this study, we investigated future changes of the Asian summer monsoon under four Shared Socioeconomic Pathway (SSP) scenarios using 19 CMIP6 models. The intensity of the South Asian summer monsoon (SASM) is projected to decrease by 2.6%, 6.3%, 10.1%, and 11.1%, while the East Asian summer monsoon (EASM) intensity is projected to increase by 4.6%, 7.9%, 7.4%, and 9.8% until the end of the 21st century for SSP126, SSP245, SSP370, and SSP585 scenarios, respectively. Moreover, summer precipitation in Asia is projected to increase remarkably in 2015–2099 under all four scenarios. The inconsistent warming trends over the Tibetan Plateau (TP), Northwest Pacific, and tropical Indian Ocean would greatly impact the monsoon circulations. The upper-troposphere warming trend over the surrounding oceans is remarkably greater than that over the TP, while the near-surface warming trend over the surrounding oceans is smaller than that over the TP. The decrease of upper-troposphere TC between the TP and tropical Indian Ocean results in a weakening of the SASM circulation. The enhancement of the lower-troposphere TC between the TP and Northwest Pacific would strengthen the EASM circulation. Moisture budget analysis shows that the water-vapor would increase in the future, which would thermodynamically enhance summer precipitation through the anomalous vertical moisture transport associated with mean flow. The strengthening of the meridional circulation of the EASM would increase monsoon precipitation, while the weakening of zonal circulation of the SASM would dynamically reduce South Asian summer precipitation.