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‘Thermohaline front’ off the east coast of India and its generating mechanism

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Abstract

Physical oceanography measurements reveal a strong salinity (0.18 psu km−1) and temperature (0.07 °C km−1) front off the east coast of India in December 1997. T–S diagrams suggest lateral mixing between the fresh water at the coast and the ambient warmer, saltier water. This front seems to be the result of southward advection of fresh and cool water, formed in the northern Bay of Bengal during the monsoon, by the East Indian Coastal Current, as suggested by the large-scale salinity structure in the SODA re-analysis and the anti-cyclonic gyre in the northwestern Bay of Bengal during winter. The data further reveals an offshore front in January, which appears to be the result of a meso-scale re-circulation around an eddy, bringing cold and freshwater from the northern Bay of Bengal further away from the shore. Our cruise data hence illustrates that very strong salinity fronts can appear in the Bay of Bengal after the monsoon, as a result of intense coastal circulation and stirring by eddies.

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Acknowledgments

Authors are thankful to Shri. S. Ananthanarayanan, Director, NPOL, for the motivation and encouragement to carry out this study. The courteous efforts of the commanding officer, officers, and crew of INS Sagardhwani in smoothly conducting the mission are gratefully acknowledged.

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Authors and Affiliations

  1. Naval Physical and Oceanography Laboratory, Kochi, 682021, India

    Panangattu Viswanathan Hareesh Kumar, Basil Mathew, Akula Raghunadha Rao, Puvvala Surya Venkata Jagadeesh, Kalarickal Gopalan Radhakrishnan & Thiyyadi Nandakumar Shyni

  2. National Institute of Oceanography, Goa, India

    Madathiparambil Ranganatha Ramesh Kumar

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  1. Panangattu Viswanathan Hareesh Kumar
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  2. Basil Mathew
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  3. Madathiparambil Ranganatha Ramesh Kumar
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  4. Akula Raghunadha Rao
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  6. Kalarickal Gopalan Radhakrishnan
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  7. Thiyyadi Nandakumar Shyni
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Correspondence to Panangattu Viswanathan Hareesh Kumar.

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Hareesh Kumar, P.V., Mathew, B., Ramesh Kumar, M.R. et al. ‘Thermohaline front’ off the east coast of India and its generating mechanism. Ocean Dynamics 63, 1175–1180 (2013). https://doi.org/10.1007/s10236-013-0652-y

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  • DOI: https://doi.org/10.1007/s10236-013-0652-y

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