Multi‐Centennial Variability of the Afro‐Asian Monsoon Linked to Atlantic Meridional Overturning Circulation

Abstract Drivers of multi‐centennial global monsoon variability remain debated, with internal variability poorly understood. Using nine CMIP6 pre‐industrial millennial simulations, we find that the Atlantic meridional overturning circulation (AMOC) correlates with multi‐centennial fluctuations in the Afro‐Asian summer monsoon (AfroASM), which includes the North African (NAFSM) and Asian (ASM) summer monsoons, but shows minimal correlation with other regional monsoons. Increased AMOC variability may amplify AfroASM fluctuations and strengthen NAFSM‐ASM coherence. Precipitation sensitivity to AMOC reaches 0.5%/Sv (ASM) and 1.57%/Sv (NAFSM). Mechanistically, we suggest that AMOC could influence NAFSM via Atlantic meridional temperature gradient and ASM via land‐sea thermal contrast and NAFSM's incursion into the Arabian Sea, altering rainfall through atmospheric circulation. Conversely, AMOC does not significantly alter temperature gradients in other regional monsoons, explaining minimal rainfall responses. These results highlight internally generated AMOC variability as critical factor for understanding Afro‐Asian hydroclimate variability.