Circulation Patterns in the Ria of Pontevedra under Extreme Forcing

Abstract

Two unusual circulation patterns were measured in the Ria of Pontevedra (NW Spain). The first one showed a positive two layered tidal pattern with water leaving the estuary through surface layers and entering it through the bottom ones. This unusual pattern is observed to depend on the particular summer stratification conditions, caused by upwelling events and solar radiation, and on the presence of easterly winds inside the estuary strong enough (~8 m s-1) to move surface water seawards. The second event showed the opposite behavior with a negative two layered tidal pattern with water leaving the estuary through bottom layers and entering it through the surface ones. This pattern is maintained by the existence of two water masses with different densities at intermediate layers.