Influence of atmospheric modes on coastal upwelling along the western coast of the Iberian Peninsula, 1985 to 2005

Abstract

Using night-time weekly sea surface temperatures (1985 to 2005), we analysed how several European regional patterns of atmospheric variation influenced coastal upwelling along the western coast of the Iberian Peninsula. The regional patterns of atmospheric variation considered were: the North Atlantic Oscillation, the East Atlantic pattern, the Scandinavia pattern, the East Atlantic/Western Russia pattern and the Europe Polar/Eurasia pattern (NAO, EA, SCA, EA/WR and POL, respectively). The upwelling index along the entire coast was calculated as the difference between coastal and oceanic sea surface temperature at the same latitude for 25 locations distributed from 37 to 43N. Relationships with atmospheric circulation modes during the upwelling season (July to October) show that the main upwelling anomaly variability can be explained in terms of the EA, showing a significant negative correlation along the entire western coast. The NAO pattern is the second most influential atmospheric mode, with influence on the upwelling index showing a significant positive correlation only between 38 and 41N.