The CCI SST Analysis Product consists of daily, spatially complete fields of SST, obtained by combining the orbit data from the AVHRR (Advanced Very High Resolution Radiometer) and ATSR (Along Track Scanning Radiometer) Long Term products, using optimal interpolation to provide SSTs where there were no measurements (a single file per day; 0.05° regular latitude- longitude grid). These data start in September 1991. The SSTs correspond approximately to the daily average of the temperature of the water at 20 cm depth. Uncertainty estimates are provided for each value.The data are stored in NetCDF-4 format files. Data arrays in NetCDF files are known as ‘variables’ and each variable has metadata stored with it. Please read the ESA CCI SST Product User Guide, available in the linked documentation before using the data. There is also a Quick Start Guide.