Atlantic Meridional Overturning Circulation Slowdown Modulates Atmospheric Rivers in a Warmer Climate

Mohima Sultana Mimi, Wei Liu, Weiming Ma and Gang Chen

Abstract

The slowing of the Atlantic meridional overturning circulation (AMOC) under anthropogenic warming has been suggested to significantly impact Earth’s climate. Here, we isolate and quantify the AMOC impact on atmospheric rivers (ARs) across the twenty-first century using coupled climate model simulations. We find that a weakened AMOC promotes AR frequency in mid-latitudes by intensifying the prevailing westerly winds, especially at the west coast of North America, which dramatically enhances AR-induced precipitation in wintertime California. Aside from dynamic processes, the weakened AMOC can also modulate ARs through thermodynamic processes. It reduces AR frequency and related precipitation over the Arctic and Greenland while increasing AR frequency and associated precipitation along the eastern coast of South America and around Antarctica, owing primarily to AMOC-induced moisture decrease and increase in the Northern and Southern Hemispheres, respectively. Our findings highlight the role of the AMOC in future regional hydroclimate and climate extreme shift.

Gang Chen

Professor, Dept. of Atmospheric and Oceanic Sciences, University of California, Los Angeles

Math Sci Building 7149, Los Angeles, CA 90095

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Atlantic Meridional Overturning Circulation Slowdown Modulates Atmospheric Rivers in a Warmer Climate

Published in Nature Communications, 2026

Recommended citation: Mohima Sultana Mimi, Wei Liu, Weiming Ma and Gang Chen, 2026: Atlantic Meridional Overturning Circulation Slowdown Modulates Atmospheric Rivers in a Warmer Climate, Nature Communications, doi:10.1038/s41467-026-72555-w.

Abstract

The slowing of the Atlantic meridional overturning circulation (AMOC) under anthropogenic warming has been suggested to significantly impact Earth’s climate. Here, we isolate and quantify the AMOC impact on atmospheric rivers (ARs) across the twenty-first century using coupled climate model simulations. We find that a weakened AMOC promotes AR frequency in mid-latitudes by intensifying the prevailing westerly winds, especially at the west coast of North America, which dramatically enhances AR-induced precipitation in wintertime California. Aside from dynamic processes, the weakened AMOC can also modulate ARs through thermodynamic processes. It reduces AR frequency and related precipitation over the Arctic and Greenland while increasing AR frequency and associated precipitation along the eastern coast of South America and around Antarctica, owing primarily to AMOC-induced moisture decrease and increase in the Northern and Southern Hemispheres, respectively. Our findings highlight the role of the AMOC in future regional hydroclimate and climate extreme shift.

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