ENSO control on the south Asian monsoon through the length of the rainy season

Goswami, BN and Xavier, Prince K (2005) ENSO control on the south Asian monsoon through the length of the rainy season. In: Geophysical Research Letters, 32 . L18717:1-4.

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Abstract

Being an integral effect of sub-seasonal rain spells over the season, the seasonal mean south Asian monsoon (SAM) rainfall could be affected by change in the length of the rainy season (LRS). An objective definition of the duration of the SAM season has, however, been lacking. Here we show that the meridional gradient of tropospheric temperature (\Delta TT) over the SAM region controls the LRS and defines the SAM season. It is further shown that ENSO induces decreased SAM rainfall by regulating the LRS. The atmospheric response to tropical sea surface temperature (SST) over the tropical Pacific during an evolving El Niño reduces \Delta TT over the SAM region and shortens LRS by delaying the onset and advancing the withdrawal. The strong negative correlation between LRS and ENSO related SST has remained steady and provides basis for improved prediction of seasonal mean SAM rainfall variability.

Item Type:	Journal Article
Publication:	Geophysical Research Letters
Publisher:	American Geophysical Union
Additional Information:	Copyright of this article belongs to the American Geophysical Union
Keywords:	Global Change:Climate variability;Global Change: Climate dynamics;Atmospheric Processes: Tropical meteorology;Atmospheric Processes: Climatology;Oceanography: Physical: ENSO;
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	23 Apr 2007
Last Modified:	19 Sep 2010 04:37
URI:	http://eprints.iisc.ac.in/id/eprint/10595

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