Validation of AVHRR pathfinder SST's over the Mediterranean Sea

Pathfinder Sea Surface Temperatures (SST) have been validated for the Mediterranean Sea using independent data obtained from MEDATLAS CTD and XBT casts. The Mean Bias is, in most of the case less than 0.5° C, with a mean value of 0.2 °C. The bias was uncorrelated to the number of Mediterranean matchups points used to evaluate the coefficients of the SST Pathfinder algorithm. This implies that Pathfinder data over the Mediterranean Sea represents a coherent time series of temperature that can be used for climatological applications. As an example of such an application the time series of the mean Mediterranean SST is discussed for the entire period of available data (1985-1996). The analysis shows evidence of interannual variability but does not suggest an evident increasing trend for SST as suggested by previous works. Comparison with corresponding meteorological data (COADS) confirms the close correlation between meteorological forcings and SST field.