Seasonal variability of mixed layer in the central Arabian Sea and its implication on nutrients and primary productivity
IR@NIO: CSIR-National Institute Of Oceanography, Goa
View Archive Info| Field | Value | |
| Creator |
PrasannaKumar, S.
Narvekar, J. |
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| Date |
2006-06-17T13:41:41Z
2006-06-17T13:41:41Z 2005 |
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| Identifier |
Deep-Sea Research II, vol.52, 1848-1861
0967-0645 http://drs.nio.org/drs/handle/2264/125 |
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| Description |
The upper layers of the ocean play an important role in the regulation of the ocean-atmosphere as a coupled system. The Arabian Sea, situated in the western part of the northern Indian Ocean, participates in the intense air-sea exchange processes associated with the semi-annually reversing monsoons. During winter monsoon the weak northeast trade wind brings cool, dry continental air while during the summer monsoon the strong southwest wind brings humid maritime air into the Arabian Sea. It is natural to expect that these semiannual atmospheric forcing would modulate the thickness of the upper ocean. The seasonal variability of the mixed layer in the central Arabian Sea (equator to 25oN and 62oE to 66o) was studied using hydrographic data from NODC and INODC, while atmospheric forcing responsible for the observed changes were explored using meteorological data from COADS and FSU winds. The mixed layer depth (MLD) and sea surface temperature (SST) in the central Arabian Sea, to a large extent was regulated by the incoming solar radiation and wind forcing. The Ekman dynamics associated with the Findlater Jet controlled the mixed layer depth during summer monsoon, while in winter the cooling and convective mixing regulated the MLD. We speculate that the deep mixed layer during February-March in the southern region is associated with that of the Rossby wave propagation. During spring and fall Intermonsoons, the weak winds along with strong incoming solar radiation lead to the formation of thin, warm and stratified mixed layer. We show that biological productivity of the Arabian Sea is rigidly coupled to the seasonal cycle of MLD, which regulates the nutrient levels in the euphotic zone.
We thank G.V. Reddy for extracting hydrograhy data and James N. Stricherz for providing FSU winds. Jayu Narvekar acknowledge the financial support from CSIR. |
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| Format |
1346253 bytes
application/pdf |
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| Language |
en
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| Publisher |
Elsevier
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| Subject |
Mixed layer
Sea surface Temperature Upwelling Advection Ekman dynamics Findlater Jet Wind stress curl winter cooling convective mixing Rossby wave propagation nutirents chlorophyll Sub-surface chlorophyll maxima oligotrophic euphotic zone stratification Primary productivity |
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| Title |
Seasonal variability of mixed layer in the central Arabian Sea and its implication on nutrients and primary productivity
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| Type |
Article
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