Publication Date:
2022-05-26
Description:
© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kantha, L., Weller, R. A., Farrar, J. T., Rahaman, H., & Jampana, V. A note on modeling mixing in the upper layers of the Bay of Bengal: importance of water type, water column structure and precipitation. Deep-Sea Research Part II-Topical Studies in Oceanography, 168, (2019): 104643. doi: 10.1016/j.dsr2.2019.104643.
Description:
Turbulent mixing in the upper layers of the northern Bay of Bengal is affected by a shallow layer overlying the saline waters of the Bay, which results from the huge influx of freshwater from major rivers draining the Indian subcontinent and from rainfall over the Bay during the summer monsoon. The resulting halocline inhibits wind-driven mixing in the upper layers. The brackish layer also alters the optical properties of the water column. Air-sea interaction in the Bay is expected to play a significant role in the intraseasonal variability of summer monsoons over the Indian subcontinent, and as such the sea surface temperature (SST) changes during the summer monsoon are of considerable scientific and societal importance. In this study, data from the heavily instrumented Woods Hole Oceanographic Institution (WHOI) mooring, deployed at 18oN, 89.5oE in the northern Bay from December 2014 to January 2016, are used to drive a one-dimensional mixing model, based on second moment closure model of turbulence, to explore the intra-annual variability in the upper layers. The model results highlight the importance of the optical properties of the upper layers (and hence the penetration of solar insolation in the water column), as well as the temperature and salinity in the upper layers prescribed at the start of the model simulation, in determining the SST in the Bay during the summer monsoon. The heavy rainfall during the summer monsoon also plays an important role. The interseasonal and intraseasonal variability in the upper layers of the Bay are contrasted with those in the Arabian Sea, by the use of the same model but driven by data from an earlier deployment of a WHOI mooring in the Arabian Sea at 15.5 oN, 61.5 oE from December 1994 to December 1995.
Description:
LK was supported by U.S. Office of Naval Research (ONR) MISO/BoB DRI under grant number N00014-17-1-2716. RW and JTF were supported by ONR Grants N00014-13-1-0453 and N00014-17-1-2880, and the WHOI mooring was funded by Grant N00014-13-1-0453. RW was supported by ONR for the 1994–1995 deployment of the surface mooring in the Arabian Sea. HR and VJ wish to thank Dr. SSC Shenoi, the Director of INCOIS and Dr. M Ravichandran, Director, NCPOR for the encouragement and support to carry out this study. This work was supported by the Ministry of Earth Sciences (MoES), Govt. of India. This is also INCOIS Contribution number 349.
Keywords:
Bay of Bengal
;
Arabian sea
;
Mixing in the upper layers
;
Second moment closure
;
Turbulence
;
WHOI mooring
;
OMNI mooring
;
Water type
;
Solar insolation
;
Precipitation
Repository Name:
Woods Hole Open Access Server
Type:
Article
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