Tidal Dynamics and Residual Circulation in a Well-Mixed Inverse Estuary

Autor: Guillermo Gutiérrez de Velasco, Clinton D. Winant
Rok vydání: 2003
Předmět:
Zdroj: Journal of Physical Oceanography. 33:1365-1379
ISSN: 1520-0485
0022-3670
DOI: 10.1175/1520-0485(2003)033<1365:tdarci>2.0.co;2
Popis: The tidal and residual circulations in Laguna San Ignacio (LSI), a well-mixed evaporative lagoon located on the Pacific coast of the Baja California peninsula in Mexico, is described based on surveys and moored observations. At tidal periods pressure and axial current fluctuations are about one-quarter of a period out of phase, and so the tidal wave is close to standing. Pressure fluctuations increase and axial currents decrease with distance from the ocean. The fluctuating axial momentum balance is nonlinear and involves local acceleration, advection, barotropic pressure gradients, and friction. The structure of the residual circulation depends on the internal Froude number Fri, a measure of the relative strength of tidal and buoyancy forcing. Most of the time, Fr i is large and the residual flow is laterally variable, driven by the tidally averaged nonlinear advective terms. The sense of this residual circulation is shown to depend on the lateral structure of the tidal stress and is away from the ocean in the deep channels when the tidal wave is standing, as in LSI, and in the opposite direction for a progressive wave. During neap tides, when Fri is small, the residual circulation is vertically stratified, with a dense near-bottom flow toward the ocean and relatively fresh inflow at the surface.
Databáze: OpenAIRE