These are gridded Sea Surface Height Anomalies (SSHA) above a mean sea surface, on 1/6th degree grid every 5 days. It contains interim heights, with delay around 4 weeks. There is a more accurate dataset available, with delay of about 3 months at http://dx.doi.org/10.5067/SLREF-CDRV2.The gridded data are derived from the SSHA data of TOPEX/Poseidon, Jason-1, Jason-2 and Jason-3 plus ERS-1, ERS-2, Envisat, SARAL-AltiKa, CRyosat-2, depending on the date, from the level 2 swath data derived from the RADS database. The gridding is done by the kriging method. The date given in the data is the center of the 5 day window.