Salinity Induced Horizontal Estuarine Circulation

A finite difference approximation to the equations of motion without the field acceleration terms, and the salt conservation equation with an isotropic diffusion coefficient, are used to model the circulation of a rectangular basin having the gross dimensional characteristics of a bar-built estuary. The recursion relations include the dynamic effects of horizontal salinity variations. Two cases are examined; in the first case the basin has a constant depth and in the second case the bottom slope varies linearly across the basin. The resulting patterns of circulation are qualitatively analyzed using a vorticity equation. The analysis indicates that the dynamic effects of horizontal salinity gradients can be significant in controlling the circulation in localized sections of the basin.