Seasonal, Interannual and Long-Term Variability of Sea Surface Temperature in the NW Iberian Upwelling, 1982–2020

Here the seasonal, inter-annual and long-term variability of satellite-derived sea surface temperature (SST) was analyzed in the NW Iberian margin from 1982 to 2020 to explore spatial differences at high (5-km) resolution. In-situ temperature measurements from five coastal buoys were used to validate the satellite-derived SST data, discarding pixels from areas close to the shoreline. Regional SST increased significantly from 0.07 to 0.25°C per decade, with the lowest rates in shelf waters directly affected by seasonal coastal upwelling. Upwelling filaments also contributed to dampen the temperature increase in the adjacent slope and ocean waters. The spatial variability observed in the amplitude and timing of the seasonal cycle of SST is directly related to hydrography and circulation patterns of the region such as upwelling events during summer and the development of the river's buoyant plume and the warm Iberian Poleward Current during winter.