Physical forcing of the hydrography of the Ria de Vigo mouth

Abstract

The Ria de Vigo is one of the four embayments located south of Cape Finisterre, along the northwest Atlantic coast of the Iberian Peninsula. It is connected to the open sea by means of two entrances separated by the presence of the Cies Islands in the outermost part. Around 30 km southwards of the Ria de Vigo is the Minho River, which is the most important river flowing into the Western Galician coast. The main objective of this study is to investigate the hydrography of the Ria de Vigo mouth in terms of its major forcing mechanisms, identifying their influence on the establishment of the observed patterns. For this purpose, correlations between wind, air temperature and Minho River discharge over the salinity and temperature were computed. When comparing both mouths of the Ria de Vigo, the water temperature is colder at the southern mouth than at the northern one. The results showed a negative correlation between bottom salinity and alongshore wind, which could be related to upwelling events that pump salt water into the estuary mouth. At the northern mouth, the major forcing was the air temperature. The salinity increase from south to north revealing that the observed low values may be induced by the Minho freshwater discharge. The temperature is weakly dependent on the Minho river discharge and closely related to the air temperature pattern, and the salinity is closely related to wind variability and to the Minho River discharge.