Figures show sea surface temperatures and anomalies compared to the normals and are calculated and interpolated from measurements in the infrared range based on geostationary and polar-orbiting weather satellites.
One map is calculated per day. Only satellite measurements taken at night are used as they represent the temperature in the upper few meters of the water column much better than measurements taken at daytime.
Measurements of sea surface temperature are based on observations from up to 10 different satellites that measure in both the infrared and microwave range. Satellite observations are from the Ocean and Sea Ice Satellite Application Facility (www.osi-saf.org) and the the Group for High-Resolution Sea Surface Temperature (www.ghrsst.org).