Pedro Montero

A two-dimensional particle tracking model for pollution dispersion in A Coruna and Vigo Rias (NW Spain)

A two-dimensional hydrodynamic model coupled to a particle tracking model is applied to study the dispersion processes and residence time in two Galician rias (A Coruna and Vigo, NW Spain) under summer conditions. In A Coruna a long residence time was found in the harbour area due to the existence of a dock, and a short one in the river area. On the contrary, in Vigo, the residence time is smaller in the harbour area, due to the Rande Strait, beyond which the river effect is negligible.

Hydrography of the Pontevedra Ria: Intra-annual spatial and temporal variability in a Galician coastal system (NW Spain)

In order to ameliorate the dearth of existing scientific knowledge concerning the hydrography of the Pontevedra Ria, a systematic investigation was carried out between Octo- ber 1997-98. Salinity variations were closely related to river discharge whereas bottom wa- ters presented oceanic characteristics over the whole year. Current was controlled by tide, river discharge, and wind in the internal ria where the highest velocities were directed along the ria channel with a low transverse component. Favorable atmospheric conditions in spring induced coastal upwelling up the continental shelf. In May the upwelling was sufficiently strong to be detected in the inner ria and intensified in July and August, cooling the ria water to 12 o- 14oC. Upwelling ceased in September, and from November to March seawater trans- ported by the poleward current (35.9; 15oC) was detected on the shelf. From January until March, unanticipated favorable upwelling conditions provoked an influx of poleward inside the ria. Ria intrusion of poleward water and association with occasional winter upwelling conditions has not been observed previously. Isopycnic three-dimensional (3-D) surface and 2-D isopycnal maps show that with high fiver runoff or intense upwelling, lower-salinity water leaves the ria near the northern margin in the surface layer. Under negative upwelling conditions, the water is partially dammed inside the ria and exits the ria when the wind speed falls. During upwelling events, ENACW penetrated the ria, especially near the southern shore. Arrival of ENACW at the northern entrance impedes the outward water flow through this mouth.