This readme file gives information on the format of the files containing the regional ionospheric and tide corrections provided by NOVELTIS in the frame of the CP4O project. The files are in netcdf format and contain the following variables : - Time in seconds wrt CryoSat reference (01/01/2000 00:00) - Longitude - Latitude - Ionosphere correction (SPECTRE maps, NOVELTIS) - Tide correction (COMAPI atlas, NOVELTIS/CNES project) Both corrections are provided as in the GDR products, which means that they must be used as usual : SSH=altitude - (range + corrections). The flag value is the same as in the GDR (32767). The two corrections were only computed for the data over Europe, where the corrections are available, and for the period between 01/2011 and 01/2013, corresponding to the data provided by ESA to NOVELTIS. The tide correction only contains the ocean tide contribution (no loading tide). To obtain the total tide correction (geocentric tide), the loading tide must be added from another model (total tide correction = ocean tide + loading tide). The COMAPI ocean tide atlas is compatible with the FES2004 loading tide. For any further questions, please contact mathilde.cancet@noveltis.fr or eric.jeansou@noveltis.fr v1.0 : Addition of the month 01/2013. v2.0 : Addition of missing tracks in LRM mode.