Response of the Low-Level Jet to Precession and Its Implications for Proxies of the Indian Monsoon

Jalihal, C and Srinivasan, J and Chakraborty, A (2022) Response of the Low-Level Jet to Precession and Its Implications for Proxies of the Indian Monsoon. In: Geophysical Research Letters, 49 (2).

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Abstract

The long-term variations in the South Asian monsoon have been inferred based on the variations in the ocean productivity along the western coast of the Arabian Sea. The variations in ocean productivity were previously thought to be primarily influenced by the intensity of upwelling. Here, using idealized precession experiments in fully coupled climate models, we have shown that the area as well as the region of maximum upwelling change with precession. When summer occurs at perihelion (stronger summer insolation and monsoon precipitation), the area of upwelling is narrow. In contrast, during summer at aphelion (weaker summer insolation and monsoon precipitation), upwelling occurs over a broader region. This is due to the effect of convective heating over northeastern Africa and the western equatorial Indian Ocean on the width and meridional location of the low-level jet. Therefore, the upwelling inferred from proxies does not necessarily indicate the Indian summer monsoon strength. © 2022. American Geophysical Union. All Rights Reserved.

Item Type:	Journal Article
Publication:	Geophysical Research Letters
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to John Wiley and Sons Inc
Keywords:	Climate change; Climate models; Incident solar radiation; Productivity, Asian monsoon; Convective heating; Coupled climate model; Fully-coupled; Indian monsoon; Low-level jet; Model-proxy; Monsoon precipitation; Precession; Upwelling, Atmospheric thermodynamics
Department/Centre:	Division of Mechanical Sciences > Divecha Centre for Climate Change Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	17 Feb 2022 06:39
Last Modified:	17 Feb 2022 06:39
URI:	http://eprints.iisc.ac.in/id/eprint/71322

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