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Seasonality and Buoyancy Suppression of Turbulence in the Bay of Bengal
Author(s) -
Thakur Ritabrata,
Shroyer Emily L.,
Govindarajan Rama,
Farrar J. Thomas,
Weller Robert A.,
Moum James N.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl081577
Subject(s) - bay , monsoon , turbulence , geology , oceanography , climatology , advection , salinity , upwelling , bengal , eddy diffusion , buoyancy , environmental science , geography , meteorology , physics , quantum mechanics , thermodynamics
A yearlong record from moored current, temperature, conductivity, and four mixing meters ( χ pods) in the northernmost international waters of the Bay of Bengal quantifies upper‐ocean turbulent diffusivity of heat ( K t ) and its response to the Indian monsoon. Data indicate (1) pronounced intermittency in turbulence at semidiurnal, diurnal, and near‐inertial timescales, (2) strong turbulence above 25‐m depth during the SW (summer) and NE (winter) monsoon relative to the transition periods (compare K t > 10 −4 m 2 /s to K t ∼ 10 −5 m 2 /s, and (3) persistent suppression of turbulence ( K t < 10 −5 m 2 /s) for 3 to 5 months in the latter half of the SW monsoon coincident with enhanced near‐surface stratification postarrival of low‐salinity water from the Brahmaputra‐Ganga‐Meghna delta and monsoonal precipitation. This suppression promotes maintenance of the low‐salinity surface waters within the interior of the bay preconditioning the upper northern Indian Ocean for the next year's monsoon.