Hydrography and circulation in the western Bay of Bengal during the northeast monsoon

Author(s): Shetye SR, Gouveia AD, Shankar D, Shenoi SSC, Vinayachandran PN, et al.

Abstract

The Bay of Bengal, a semienclosed tropical basin that comes under the influence of monsoonal wind and freshwater influx, is distinguished by a strongly stratified surface layer and a seasonally reversing circulation. We discuss characteristics of these features in the western Bay during the northeast monsoon, when the East India Coastal Current (EICC) flows southward, using hydrographic data collected during December 1991. Vertical profiles show uniform temperature and salinity in a homogeneous surface layer, on average, 25 m deep but shallower northward and coastward. The halocline, immediately below, is approximately 50 m thick; salinity changes by approximately 3 parts per thousand. About two thirds of the profiles show temperature inversions in this layer. Salinity below the halocline hardly changes, and stratification is predominantly due to temperature variation. The halocline is noticeably better developed and the surface homogeneous layer is thinner in a low-salinity plume that hugs the coastline along the entire east coast of India. The plume is, on average, 50 km wide, with isohalines sloping down toward the coast. Most prominent in the geostrophic velocity field is the equatorward EICC. Its transport north of about 13° N, computed with 1000 dbar as the level of reference, varies between 2.6 and 7.1 × 106 m3 s−1; just south of this latitude, a northwestward flow from offshore recurves and merges with the coastal current. At the southern end of the region surveyed, the transport is 7.7 × 106 m3 s−1. Recent model studies lead us to conclude that the EICC during the northeast monsoon is driven by winds along the east coast of India and Ekman pumping in the interior bay. In the south, Ekman pumping over the southwestern bay is responsible for the northwestward flow that merges with the EICC.

 

Similar Articles

Wind-driven coastal upwelling along the western boundary of the Bay of Bengal during the southwest monsoon

Author(s): Shetye SR, Shenoi SSC, Gouveia AD, Michael GS, Sundar D, et al.

The Western Boundary Current of the seasonal subtropical gyre in Bay of Bengal

Author(s): Shetye SR, AD Gouveia, SSC Shenoi, DSundar, GSMichael, et al.

Observation of the western boundary current of the Bay of Bengal Deep-Sea Res 44:135-145

Author(s): Sanilkumar KV, Kuruvilla TV, Jogendranath D, and Rao RR

Eddy-mediated biological productivity in the Bay of Bengal during fall and spring intermonsoons Deep Sea Research II 54: 1619-1640

Author(s): Prasanna Kumar S, Nuncio M, Ramaiah N, Sardesai S, Narvekar, Jayu, Fernandes, Veronica, & Paul, Jane T

Are eddies nature’s trigger to enhance biological productivity in the Bay of Bengal? Geophys Res Lett 31

Author(s): Prasanna Kumar S, Nuncio M, Narvekar J, Kumar A, Sardesai S, et al.

Seasonal cycle of physicalforcing and biological response in the Bay of BengalIndian J Mar Sci 39: 388-405

Author(s): Prasanna Kumar S, Nuncio M, Narvekar J, Ramaiah N, Sardessai S, et al

Influence of basin-scale and mesoscale physical processes onbiological productivity in the Bay of Bengal during the summer monsoon

Author(s): Muraleedharan KR, Jasmine P, Achuthankutty CT, Revichandran C, Dineshkumar PK, et al

ICES zooplankton methodology manual

Author(s): Harris RP, Wiebe PH, Lenz JH, Skjoldal R & Huntley M

Detection of Bay of Bengaleddies from Topex and in situ observations

Author(s): Gopalan AKS, GopalaKrishna VV, Ali MM, Sharma R

Forcing mechanisms of the Bay of Bengal circulation Current SciIndia 71: 753-763

Author(s): Vinayachandran PN, Shetye SR, Sengupta D, Gadgil S

Development of a subsurface chlorophyll maximum at the entrance to the Gulf of Finland, Baltic Sea

Author(s): Kononen KJ, S Hallfors, M Kokkonen, H Kuosa, J Laanemets, J Pavelson

Analysis of Marine Ecosystems

Author(s): Owen RW

Vertical flux of respiratory carbon by oceanic diel migrant biota Deep-Sea Res 37: 685–694

Author(s): Longhurst AR, Bedo A, Harrison WG, Head EJH, Sameoto DD

Zooplankton vertical migration and the active transport of dissolved organic and inorganic carbon in the Sargasso

Author(s): Steinberg DK, Carlson CA, Bates NR, Goldthwait SA, Madin LP, et al.