Numerical simulation of the tidal propagation in the coastal region of Santos (Brazil, 24°S 46°W)

A sigma vertical co-ordinate model was implemented for the coastal region of Santos (Brazil, 24°S 46°W), aiming at high-resolution barotropic tidal simulations. On a grid of 120×80 cells and spacing of about 1 km, tidal elevations due to the nine principal constituents were specified at the open boundaries, based on a model of the shelf. The coastal model results were compared to observations and harmonic predictions in the Port of Santos. Tidal analyses of time series relative to 5527 wet points, with 696 hourly results of elevations and surface currents each, generated maps of the co-tidal lines and axes of the current ellipses, which numerical values were compared to harmonic constants of some coastal stations. The obtained maps indicate the main characteristics of the tides in the coastal region of Santos, such as the areas of amplification and main propagation directions. The model results generated maps of the potential, kinetic and total energies associated to the tides. Residual depth-mean currents show tidal eddies related to coastal geometry and bottom topography. Vertical profiles of the tidal currents have nearly constant intensities and directions along the vertical, from the surface to the top of the bottom layer. The implemented modeling may be used for operational predictions of tides and tidal currents in the study area, especially when considering grid nestings in the shallow inner regions.