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Reduced near-surface thermal inversions in 2005-06 in the southeastern Arabian Sea (Lakshadweep Sea)

DRS at CSIR-National Institute of Oceanography

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Title Reduced near-surface thermal inversions in 2005-06 in the southeastern Arabian Sea (Lakshadweep Sea)
 
Creator Nisha, K.
Rao, S.A.
Gopalakrishna, V.V.
Rao, R.R.
GirishKumar, M.S.
Pankajakshan, T.
Ravichandran, M.
Rajesh, S.
Girish, K.
Johnson, Z.
Anuradha, M.
Gavaskar, S.S.M.
Suneel, V.
Krishna, S.M.
 
Subject thermal inversions
monsoon
sea surface temperature
Coastal Current
 
Description Repeat XBT transects made at near-fortnightly intervals in the Lakshadweep Sea (southeastern Arabian Sea) and ocean data assimilation products are examined to describe the year-to-year variability in the observed near-surface thermal inversions during the winter seasons of 2002-06. Despite the existence of a large low-salinity water intrusion into the Lakshadweep Sea, there was an unusually lower number of nearsurface thermal inversions during the winter 2005/06 compared to the other winters. The possible causative mechanisms are examined. During the summer monsoon of 2005 and the following winter season, unusually heavy rainfall occurred over the southwestern Bay of Bengal and the Lakshadweep Sea compared to other years in the study. Furthermore, during the winter of 2005, both the East India Coastal Current and the Winter Monsoon Current were stronger compared to the other years, transporting larger quantities of low salinity waters from the Bay of Bengal into the Lakshadweep Sea where a relatively cooler near-surface thermal regime persisted owing to prolonged upwelling until November 2005. In addition, the observed local surface wind field was relatively stronger, and the net surface heat gain to the ocean was weaker over the Lakshadweep Sea during the postmonsoon season of 2005. Thus, in winter 2005/06, the combination of prolonged upwelling and stronger surface wind field resulting in anomalous net surface heat loss caused weaker secondary warming of the near-surface waters in the Lakshadweep Sea. This led to a weaker horizontal sea surface temperature (SST) gradient between the Lakshadweep Sea and the intruding Bay of Bengal waters and, hence, a reduced number of thermal inversions compared to other winters despite the presence of stronger vertical haline stratification.
 
Date 2009-11-17T11:52:18Z
2009-11-17T11:52:18Z
2009
 
Type Journal Article
 
Identifier Journal of Physical Oceanography, vol.39(5); 1184-1199
http://drs.nio.org/drs/handle/2264/3451
 
Language en
 
Rights An edited version of this paper was published by American Meteorological Society. Copyright [2009] American Meteorological Society
 
Publisher American Meteorological Society