Increased summer monsoon rainfall over Northwest India caused by Hadley cell expansion and Indian Ocean warming

Joseph, Ligin; Skliris, Nikolaos; Dey, Dipanjan; Marsh, Robert; Hirschi, Joël. 2024 Increased summer monsoon rainfall over Northwest India caused by Hadley cell expansion and Indian Ocean warming. Geophysical Research Letters, 51 (16). 10.1029/2024GL108829

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Official URL: http://dx.doi.org/10.1029/2024GL108829

Abstract/Summary

From 1979 to 2022, the summer monsoon precipitation has increased by a substantial 40% over Northwest India compared to the 1980s. This wetting trend aligns with the future projections of the Coupled Model Intercomparison Project 6 (CMIP6). The observationally constrained reanalysis data indicates that significant sea surface warming in the western equatorial Indian Ocean and the Arabian Sea is likely driving this increase in rainfall by enhancing the cross-equatorial monsoonal flow and associated evaporation. We demonstrate that the strengthening of the cross-equatorial monsoon winds is due to the rapid warming of the Indian Ocean and the enhanced Pacific Ocean trade winds, which result from the poleward shift and expansion of the Hadley cell. These strengthened winds boost the latent heat flux (evaporation), leading to increased moisture transport to Northwest India.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2024GL108829
ISSN:	0094-8276
Additional Keywords:	Indian Monsoon, Indian Ocean Warming, Ocean-Atmosphere Interaction, Trade Winds, Hadley Cell Expansion
Date made live:	05 Sep 2024 16:44 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/537973

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2024GL108829

ISSN:

0094-8276

Additional Keywords:

Indian Monsoon, Indian Ocean Warming, Ocean-Atmosphere Interaction, Trade Winds, Hadley Cell Expansion

Date made live:

05 Sep 2024 16:44 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/537973