Iberian margin: the Rías

Abstract

The Iberian Upwelling System comprises the Atlantic coast of Portugal and Spain, from 37ºN to 43ºN (Fig. 2..6.1). It constitutes the northern limit of the upwelling system off Iberia–NW Africa, associated with the eastern boundary Canary Current System (Wooster et al. 1976; Barton 1998). At these latitudes, coastal winds are seasonal (Fig. 2.6.2a): northerly winds prevail from March–April to September–October (upwelling season) and southerly winds predominate the rest of the year (downwelling season). However, this seasonal cycle explains <15% of the total variability of coastal winds and >70% of which concentrates in periods of less than 1 month. The upwelling season appears as a succession of wind stress/relaxation cycles of period 10–20 days (Blanton et al. 1987; Álvarez–Salgado et al. 1993) as in other coastal upwelling system at comparable latitudes (Hill et al. 1998)