Changes of Southern Hemisphere westerlies in the future warming climate

The Southern Hemisphere westerlies (SHWs) play a key role in regulating global climate and ocean circulation, but their future changes under low to high greenhouse gas forcings remain unclear. This study investigates the long-term trends in strength and position of the SHWs and their linkage with hu...

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Bibliographic Details
Published in:Atmospheric research Vol. 270; p. 106040
Main Authors: Deng, Kaiqiang, Azorin-Molina, Cesar, Yang, Song, Hu, Chundi, Zhang, Gangfeng, Minola, Lorenzo, Chen, Deliang
Format: Journal Article
Language:English
Published: Elsevier B.V 01.06.2022
Subjects:
atmospheric circulation
climate
Climate change
Climate models
CMIP6
convection
Coupled Model Intercomparison Project
Coupled model intercomparison project phase 6
Earth and Related Environmental Sciences
Future projections
Geovetenskap och relaterad miljövetenskap
Global climates
Greenhouse gases
Greenhouse-gas forcing
Human activities
humans
Project phasis
Southern Hemisphere
Southern Hemisphere westerlies
Southern hemisphere westerly
Warming climate
Southern Hemisphere westerlies
Human activities
CMIP6
Future projections
ISSN:0169-8095
Online Access:Get full text
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Summary:The Southern Hemisphere westerlies (SHWs) play a key role in regulating global climate and ocean circulation, but their future changes under low to high greenhouse gas forcings remain unclear. This study investigates the long-term trends in strength and position of the SHWs and their linkage with human activities, based on the ERA5 reanalysis and model simulations from the Coupled Model Intercomparison Project phase 6 (CMIP6). The results show that the SHWs have intensified and shifted poleward in the recent decades, and are projected to experience divergent trends in strength and position during the 21st century under different Shared Socioeconomic Pathway (SSP) scenarios. Forced by SSP245, 370, and 585, which represent the middle to high greenhouse gas forcings, the SHWs will continue to strengthen and move southward in 2015–2099, with the largest trends induced by SSP585. Nevertheless, forced by SSP126, which implies a low greenhouse gas forcing in the future, the ongoing trends in strength and position of the SHWs will be interrupted and even reversed. Further investigation reveals that the anthropogenic forcing could have affected and will likely influence the SHWs by modulating meridional atmospheric circulation in the Southern Hemisphere. In particular, the Southern Annular Mode and the tropical Pacific convection play crucial roles in the changes of SHWs. This study links human activities to the changes in SHWs, providing important implications for climate change and its mitigation. •The Southern Hemisphere westerlies (SHWs) have strengthened and shifted poleward in the recent decades.•The SHWs are projected to intensify (weaken) during the 21st century under high (low) greenhouse gas forcing.•Human activities may play a key role in the changes of SHWs.
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ISSN:0169-8095
DOI:10.1016/j.atmosres.2022.106040