 Sea surface temperature (SST) measured from satellites in considerable spatial detail and at high frequency, is increasingly required for use in the context of operational monitoring and forecasting of the ocean, for assimilation into coupled ocean-atmosphere model systems and for applications in short-term numerical weather prediction and longer term climate change detection.Currently there are many different SST data sets available derived from satellite systems.But, scientists and operational agencies alike are presented with a bewildering set of options in terms of SST product content, coverage, spatial resolution, timeliness, format and accuracy.