Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes

Abstract The weakening of convective mass flux and the Walker circulation is one of the most robust responses to global warming. However, recent decades have seen the Pacific Walker circulation strengthen despite a weakening convective mass flux. Here, we conduct a series of prescribed sea surface t...

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Main Authors: Sarah M. Kang, Masahiro Watanabe, Veronika Gayler
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL111897
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author Sarah M. Kang
Masahiro Watanabe
Veronika Gayler
author_facet Sarah M. Kang
Masahiro Watanabe
Veronika Gayler
author_sort Sarah M. Kang
collection DOAJ
description Abstract The weakening of convective mass flux and the Walker circulation is one of the most robust responses to global warming. However, recent decades have seen the Pacific Walker circulation strengthen despite a weakening convective mass flux. Here, we conduct a series of prescribed sea surface temperature (SST) experiments to separate the effects of global warming from changes in SST patterns. The tropical‐mean convective mass flux weakens in proportion to the global warming amplitude, largely unaffected by SST pattern changes. Conversely, the Walker circulation response is sensitive to SST pattern changes, weakening with global warming if zonal SST contrast decreases or increases below a certain threshold and strengthening if the increase in SST contrast exceeds that threshold. Thus, the Walker circulation might continue to strengthen if the SST pattern effects dominate. Our results indicate that the weakening of convective mass flux alone is insufficient for projecting the Walker circulation response.
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spelling doaj-art-a7d69d458f4d4d4f9ba04c34dfddeaf72025-08-20T02:31:09ZengWileyGeophysical Research Letters0094-82761944-80072025-02-01524n/an/a10.1029/2024GL111897Common and Distinct Drivers of Convective Mass Flux and Walker Circulation ChangesSarah M. Kang0Masahiro Watanabe1Veronika Gayler2Max Planck Institute for Meteorology Hamburg GermanyAtmosphere and Ocean Research Institute University of Tokyo Kashiwa JapanMax Planck Institute for Meteorology Hamburg GermanyAbstract The weakening of convective mass flux and the Walker circulation is one of the most robust responses to global warming. However, recent decades have seen the Pacific Walker circulation strengthen despite a weakening convective mass flux. Here, we conduct a series of prescribed sea surface temperature (SST) experiments to separate the effects of global warming from changes in SST patterns. The tropical‐mean convective mass flux weakens in proportion to the global warming amplitude, largely unaffected by SST pattern changes. Conversely, the Walker circulation response is sensitive to SST pattern changes, weakening with global warming if zonal SST contrast decreases or increases below a certain threshold and strengthening if the increase in SST contrast exceeds that threshold. Thus, the Walker circulation might continue to strengthen if the SST pattern effects dominate. Our results indicate that the weakening of convective mass flux alone is insufficient for projecting the Walker circulation response.https://doi.org/10.1029/2024GL111897convective mass fluxWalker circulationglobal warmingSST pattern
spellingShingle Sarah M. Kang
Masahiro Watanabe
Veronika Gayler
Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
Geophysical Research Letters
convective mass flux
Walker circulation
global warming
SST pattern
title Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
title_full Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
title_fullStr Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
title_full_unstemmed Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
title_short Common and Distinct Drivers of Convective Mass Flux and Walker Circulation Changes
title_sort common and distinct drivers of convective mass flux and walker circulation changes
topic convective mass flux
Walker circulation
global warming
SST pattern
url https://doi.org/10.1029/2024GL111897
work_keys_str_mv AT sarahmkang commonanddistinctdriversofconvectivemassfluxandwalkercirculationchanges
AT masahirowatanabe commonanddistinctdriversofconvectivemassfluxandwalkercirculationchanges
AT veronikagayler commonanddistinctdriversofconvectivemassfluxandwalkercirculationchanges