The sea surface temperature of the West Mediterranean Sea: Historical satellite thermal data

A nine-year satellite data set of 18km/weekly scale is used to study the Western Mediterranean Basin's seasonal and interannuat thermal variability both as an indicator of the circulation variability and the long-term SST trends. In addition, this systematic data analysis is used to define a surface climatic data base w ith a spatial resolution finer than in situ data. We believe this satellite climatology can be used by modelers of either marine or atmospheric circulation to run regional models of the Western Mediterranean Basin. The analysis of this long-term series reveals that a strong interannual variability is present in both the SST averaged over the different Mediterranean sub-basins and in the patterns of the main Western Mediterranean circulation features. This variability seems to be seasonally regional dependent. An increase o 1.5° C mean SST for the entire Western Mediterranean. This unusually high value cannot be construed to be due to sensor drift because the data came from satellites and the increase was found in different seasons and sub-basins. A longer time series is needed in order to evaluate if this increasing trend is due to a long term interannual SST oscillation or a continued warming of the Western Mediterranean Sea.