Computation of density driven flows using the spectral method: application to the Arabian Gulf

Abstract

A model is described for the computation of flows in shallow seas driven by density gradient. The numerical algorithm is based on a Galerkin spectral method using eddy-viscosity eigenfunctions for the vertical coordinate and a B-grid for the horizontal coordinates. The accuracy of the algorithm is tested on two problems involving vertical density variation and Coriolis forces. The numerical model is then used to compute that part of the residual currents in the Arabian Gulf caused by density gradient, using as input a series of measurements of the density field made during the winter of 1977. The algorithm produces more accurate results in the test problems than an earlier direction-splitting algorithm by Lardner and Das [(1991) Applied Mathematical Modelling, 12, 471–488], and the computed flow in the Gulf, while generally consistent with that found in this earlier paper, does not show the irregularities near the open boundary found there, and in other earlier computations.