ON THE COMPUTATION OF FLOWS DRIVEN BY DENSITY GRADIENT - RESIDUAL CURRENTS IN THE ARABIAN GULF

A model is described for the computation of flows in shallow seas driven by density gradient. The numerical algorithm is based on a splitting method: At each time step the surface elevation and vertically integrated mass transports are computed from the depth-averaged equations; then the vertical structure of the current is obtained from the horizontal momentum equations. The accuracy of the algorithm is tested on four problems for which the exact steady-state solutions can be calculated. 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. While the basic flow pattern turns out to be as expected, the details of the flow show several surprising features. In particular, the magnitudes of the velocities are smaller by a factor of 2-5 than has been suggested by some authors.