On the sea surface temperature high in the Lakshadweep Sea before the onset of the southwest monsoon
IR@NIO: CSIR-National Institute Of Oceanography, Goa
View Archive Info| Field | Value | |
| Creator |
Shenoi, S.S.C.
Shankar, D. Shetye, S.R. |
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| Date |
2006-03-23T05:18:28Z
2006-03-23T05:18:28Z 1999-07 |
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| Identifier |
Journal of Geophysical Research, vol. 104, 15703-15712
http://drs.nio.org/drs/handle/2264/23 |
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| Description |
The north Indian Ocean becomes the warmest area of the world oceans prior to the onset of southwest monsoon in June. During this period a zonal band of high sea surface temperature (SST), the ``thermal equator'' (TE), moves over this region concurrently with the Intertropical Convergence Zone (ITCZ). Using a weekly SST data set, we show that another SST high develops off southwest India in the Lakshadweep Sea in March, well before the TE moves in to the area, and that it continues to retain its identity until the onset of monsoon. The SST high has its genesis about 6 months earlier in the Bay of Bengal. The collapse of the southwest monsoon in October and the onset of the northeast monsoon trigger downwelling coastal
Kelvin waves that propagate along the periphery of the Bay of Bengal, forcing an equatorward East India Coastal Current, which
brings low-salinity water from the bay to the southeastern Arabian Sea during the northeast monsoon (November-January). As the Kelvin
waves propagate poleward along the west coast of India after turning around Sri Lanka, they radiate downwelling Rossby waves that produce
a ``high'' in sea level off southwest India. The downwelling and the surface layer of low-salinity water provide a breeding ground for the formation of a SST high in January. By March, with the increase in solar insolation due to the northward march of the Sun and the deep stable surface layer, the high reaches a mature phase clearly
evident in the Lakshadweep Sea. By May, when the thermal equator and ITCZ move over the region, the high can be seen embedded in the
TE. We speculate that at this time the high helps in producing conditions that are conducive for genesis of the monsoon onset
vortex.
Department of Ocean Development |
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| Format |
1156573 bytes
application/pdf |
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| Language |
en
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| Publisher |
American Geophysical Union
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| Rights |
An edited version of this paper was published by AGU. Copyright [2000] American Geophysical Union
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| Subject |
Air-sea interaction
Monsoon onset vortex Arabian Sea Indian Ocean Ocean circulation Rossby waves Salinity ARMEX |
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| Title |
On the sea surface temperature high in the Lakshadweep Sea before the onset of the southwest monsoon
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| Type |
Preprint
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