SST diurnal variability in the North Sea and the Baltic Sea

► We use 5 years of hourly SEVIRI SST observations in the North and Baltic Sea. ► Create SEVIRI foundation fields to avoid multiple sensor biases from blended products. ► Characterize diurnal warming in North. Europ. Seas (amplitude, spatial distribution). ► Inspect variability of factors that may promote diurnal warming (wind, water turbid). ► Apply a simple model for the seasonal variation of the penetration depth.