Diurnal SST warming in the Bay of Biscay: satellite measurements and model prediction

NOAA AVHRR data from the Bay of Biscay between 1988 and 1990 have been examined in order to extract information on the fluctuations of sea surface temperature (SST) at the diurnal time scale.The temporal and spatial distributions of diurnal warming in the area are obtained.The diurnal warming occurs during the summer months.Large diurnal warming in excess of 1℃ is found within 100 km along the west coast of France and within 30 km along the north coast of Spain.In the central Bay of Biscay the diurnal warming is typically about 0.5℃.The diurnal warming up to 6℃ is observed occasionally in the coastal areas where the wind speed is very low.
A one-dimensional oceanic mixed-layer model has been used to simulate the diurnal warming.The results demon-strate that the diurnal warming increases with the decrease of the wind speed and the increase of the net heat flux.The comparison shows that the model results are in good agreement with the satellite measurements.