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On the relative roles of El Nino and Indian Ocean Dipole events on the monsoon onset over Kerala

DRS at CSIR-National Institute of Oceanography

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Title On the relative roles of El Nino and Indian Ocean Dipole events on the monsoon onset over Kerala
 
Creator Sankar, S.
RameshKumar, M.R.
Reason, C.
 
Subject El Nino
Indian Ocean
monsoon
surface temperature
 
Description Interannual variations of the monsoon onset over Kerala (MOK) have been studied using data from over 60 years (1948-2009) of NCEP/NCAR reanalysis and outgoing long-wave radiation. The sea surface temperature fields over the North Indian Ocean associated with the MOK have been examined in association with El Nino and Indian Ocean Dipole (IOD) events which originate in the Pacific and Indian Ocean, respectively. An analysis of the tropical convective maximum showed significant differences in its strength and location during the El Nino, IOD, early, normal, and delayed MOK composites. Further, we also looked into the role of the convective systems formed over the Arabian Sea and Bay of Bengal on MOK. The most significant features during early (delayed) MOK years is the abnormal persistence of westerlies (easterlies) several days prior to MOK and enhanced (suppressed) deep convection over the southeastern Arabian Sea and the southern Bay of Bengal. Moisture builds up over peninsular India several pentads prior to MOK during La Nina, negative IOD, and concurrent La Nina and negative IOD years as compared to the El Nino, positive IOD, and concurrent El Nino and positive IOD years, indicating its significant role on MOK. The monsoon Hadley cell and Walker circulations are weaker (stronger) during a delayed (early) MOK. Further, the sea surface temperature anomalies in the western Pacific are negative (positive) during delayed (early) MOK
 
Date 2011-03-09T10:54:58Z
2011-03-09T10:54:58Z
2011
 
Type Journal Article
 
Identifier Theoretical and Applied Climatology, vol.103(3-4); 2011; 359-374
http://drs.nio.org/drs/handle/2264/3803
 
Language en
 
Rights An edited version of this paper was published by Springer. This paper is for R & D pupose and Copyright [2011] Springer
 
Publisher Springer