Mediterranean Sea - High Resolution Diurnal Subskin Sea Surface Temperature Analysis

Within the Copernicus Marine Environment Monitoring Service (CMEMS), an operational Mediterranean diurnal Sea Surface Temperature (SST) product has been developed. This product provides gap-free (Level-4, L4) hourly-mean maps of sub-skin SST at 1/16° horizontal resolution over the Mediterranean Sea from 2019 to near real time, by combining infrared satellite and model analyses through optimal interpolation. This approach takes advantage of the availability of hourly SST data from the geostationary SEVIRI sensor and the CMEMS Mediterannean model analyses, the former used as the input signal source and the latter as first-guess. The resulting SST anomaly field (satellite-model) is free, or nearly free, of any diurnal cycle thus allowing to interpolate SST anomalies using satellite data acquired at different times of the day. The product is updated daily and provides 24 hourly-mean data of the previous day, centered at 00:00, 01:00, 02:00,…, 23:00 UTC. The sub-skin temperature is the temperature at the base of the thermal skin layer and it is equivalent to the foundation SST at night, but during daytime it can be significantly different under favorable (clear sky and low wind) diurnal warming conditions.