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Robust and irreversible impacts of an AMOC collapse on tropical monsoon systems: a multi-model comparison
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  • Maya Ben-Yami,
  • Peter Good,
  • Laura C Jackson,
  • Michel Crucifix,
  • Aixue Hu,
  • Oleg A. Saenko,
  • Didier Swingedouw,
  • Niklas Boers
Maya Ben-Yami
Technical University of Munich

Corresponding Author:[email protected]

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Peter Good
Met Office
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Laura C Jackson
Met Office
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Michel Crucifix
Universite catholique de Louvain
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Aixue Hu
National Center for Atmospheric Research (UCAR)
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Oleg A. Saenko
University of Victoria
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Didier Swingedouw
French National Centre for Scientific Research (CNRS)
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Niklas Boers
École Normale Supérieure
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Abstract

A collapse of the Atlantic Meridional Overturning Circulation (AMOC) would have substantial impacts on global precipitation patterns, especially in the vulnerable tropical monsoon regions. We assess these impacts using four state-of-the-art climate models with bistable AMOC. Spatial and seasonal patterns of precipitation change are remarkably consistent across models. We focus on the South American Monsoon (SAM), the West African Monsoon (WAM), the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM). Models consistently suggest substantial disruptions for WAM, ISM and EASM with shorter wet and longer dry seasons (-29.07\%,-18.76\% and -3.78\% ensemble mean annual rainfall change, respectively). Models also agree on changes for the SAM, suggesting rainfall increases overall, in contrast to previous studies. These are more pronounced in the southern Amazon (+43.79\%), accompanied by decreasing dry-season length. Consistently across models, our results suggest major rearranging of all tropical monsoon systems in response to an AMOC collapse.
01 Sep 2023Submitted to ESS Open Archive
11 Sep 2023Published in ESS Open Archive