These files constitute a time series of altimetry measurements (http://en.wikipedia.org/wiki/Radar_altimeter) created by the ENVISAT satellite (http://en.wikipedia.org/wiki/Envisat). Each file contains data from one satellite cycle, i.e. the time needed by the satellite to map the Earth completely (35 days).
Submitter: Norwegian Mapping Authority
Owner: Norwegian Mapping Authority
Version number 1