Sea Surface Temperatures

Sensors measuring emitted radiation in the infrared part of the electromagnetic spectrum can be used to derive the temperature of the surface of the Earth. GRAS has many years of experience in operational systems deriving the Sea Surface Temperature. From our own HRPT satellite receiving station GRAS can deliver operational SST data from NOAA AVHRR covering Northern Europe within 30 min of acquisition. From processing chains based on MODIS Aqua/Terra and GOES GRAS can deliver worldwide coverage of SST data within a few hours after reception.

The illustration below shows a NOAA AVHRR time series of the inner Danish waters during the summer month of August. Time series of Sea Surface Temperature is very useful for identification of currents, fronts and to provide an overview of the general circulation patterns of a particular area

The processing system at GRAS incorporates auto-correlation routines to automatically geo-reference the data to within subpixel accuracy. If needed, an automatic cloud mask can also be applied.

The accuracy of the Sea Surface Temperature maps from NOAA AVHRR data is approximately 0.5 °C and similar accuracies are found from the MODIS and GOES products. The standard spatial resolution of the Sea Surface Temperature maps is 1000 meters.

Sea Surface Temperature can be used for a wide range of applications e.g. location of fronts and currents, assimilation and validation of oceanographic models, meteorological modelling and temporal analysis of Sea Surface Temperature for global change studies.

As an example of the worldwide coverage GRAS is maintaining an operational delivery of SST data covering the Gulf of Mexico. Daily composite images are used as input to forecast modelling and are automatically processed and transferred to the client via ftp.