North Atlantic cooling triggered a zonal mode over the Indian Ocean during Heinrich Stadial 1

Abrupt changes in the Atlantic meridional overturning circulation (AMOC) are thought to affect tropical hydroclimate through adjustment of the latitudinal position of the intertropical convergence zone (ITCZ). Heinrich Stadial 1 (HS1) involves the largest AMOC reduction in recent geological time; ho...

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Bibliographic Details
Published in:Science Advances
Main Authors: Du, Xiaojing, Russell, James M., Liu, Zhengyu, Otto-Bliesner, Bette L., Oppo, Delia W., Mohtadi, Mahyar, Zhu, Chenyu, Galy, Valier V., Schefuß, Enno, Yan, Yan, Rosenthal, Yair, Dubois, Nathalie, Arbuszewski, Jennifer, Gao, Yu
Format: Text
Language:English
Published: American Association for the Advancement of Science 2023
Subjects:
Earth
Environmental
Ecological
and Space Sciences
Indian
Sunda
North Atlantic
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9812376/
http://www.ncbi.nlm.nih.gov/pubmed/36598985
https://doi.org/10.1126/sciadv.add4909
Description
Summary:Abrupt changes in the Atlantic meridional overturning circulation (AMOC) are thought to affect tropical hydroclimate through adjustment of the latitudinal position of the intertropical convergence zone (ITCZ). Heinrich Stadial 1 (HS1) involves the largest AMOC reduction in recent geological time; however, over the tropical Indian Ocean (IO), proxy records suggest zonal anomalies featuring intense, widespread drought in tropical East Africa versus generally wet but heterogeneous conditions in the Maritime Continent. Here, we synthesize proxy data and an isotope-enabled transient deglacial simulation and show that the southward ITCZ shift over the eastern IO during HS1 strengthens IO Walker circulation, triggering an east-west precipitation dipole across the basin. This dipole reverses the zonal precipitation anomalies caused by the exposed Sunda and Sahul shelves due to glacial lower sea level. Our study illustrates how zonal modes of atmosphere-ocean circulation can amplify or reverse global climate anomalies, highlighting their importance for future climate change.

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