Circulation in the Gulf of Khambhat—A Lagrangian Perspective

Aditi Mitra,V Simhadri Naidu,V Sanil Kumar

doi:10.3390/jmse8010025

Abstract

The circulation of the Gulf of Khambhat (GoK) is studied from a Lagrangian point of view using a 2D numerical model. The model-predicted tide elevation and current speed are in agreement with the observations. Seasonal variations of advection of particles are simulated by releasing 237 particles homogeneously distributed over the Gulf. After one month of simulation, no particles escaped from the GoK except a few from the southern GoK during southwest monsoon (June–September), and the advection of particles was at its maximum in the northern part. Residual eddies are present inside the GoK during the northeast (October–January) and southwest monsoon seasons. Gulf circulation is studied with the combined forcing of tide and wind for different tidal conditions, which had noticeable seasonal difference. The maximum simulated current speeds of 3.4 and 2.8 m/s are noticed during southwest monsoon near to Bhavnagar and Dahej respectively, where the tide elevations are maximum indicating that GoK is a tide-dominated system. A seasonal barrier could be found in the southern Gulf, which not only makes the Gulf circulation distinct from that of the Arabian Sea (AS), but also restricts water-mass exchange between the Gulf and AS during ebb condition. As the Gulf is a dump yard for anthropogenic wastes, the present study puts forward an effort to determine the fate of the waste from a hydrodynamic point of view.

Highlights

The western continental shelf of India is varied from south to north, and widens off Mumbai, leading into a strongly converging channel, the Gulf of Khambhat (GoK)
The barotropic circulation of the model domain reveals that GoK is directly connected to the Arabian Sea, there is a prominent dissimilarity between the circulation of the Gulf and the open sea
It should be noted that the minimal exchange of water-mass between the Arabian Sea and GoK could be a result of this kind of formation [32,33] which would be the future aspect of the study

Summary

Introduction

The western continental shelf of India is varied from south to north, and widens off Mumbai, leading into a strongly converging channel, the Gulf of Khambhat (GoK). The GoK, formerly known as the Gulf of Cambay, is a funnel-shaped indentation, situated between the Saurashtra peninsula and the mainland of Gujarat (Figure 1). The amplification of the tide inside the GoK is due to its shape and varying bottom friction coefficients [2], as well as the large width of the continental shelf off the central west coast of India [3]. Current measurements in GoK indicate a maximum current speed of 3.3 m/s and north-northwest flows during flood tide and south-southeast flows during ebb tide [5]. The main rivers that drain into the GoK are the Narmada, Tapi, Mahi and Sabarmati, and these rivers discharge a large amount of

Objectives

Methods

Results

Conclusion