In March 2025, JPL reported an error in the EGM2008 grids used in all operational missions (Jason-3, SARAL/AltiKa, CryoSat-2, Sentinel-3, Sentinel-6).
The issue in the former version of the geoid is that it was that it there was a misinterpretation of the location of the grid points. The original file released by NGA in 2008, from which the netCDF version was compiled, was at the corner of each grid cell, starting at 0ºE, 90ºN. However, the assumption in the netCDF conversion was that the grid points were at the centre of each grid cell.
The resulting error in the EGM2008 geoid can be up to ±46 cm depending on the location, as shown here:
Unfortunately, the same error slipped into RADS as well.
Thus the field geoid_egm2008 is to be replaced on all missions:
In March 2025, JPL reported an error in the EGM2008 grids used in all operational missions (Jason-3, SARAL/AltiKa, CryoSat-2, Sentinel-3, Sentinel-6).
The issue in the former version of the geoid is that it was that it there was a misinterpretation of the location of the grid points. The original file released by NGA in 2008, from which the netCDF version was compiled, was at the corner of each grid cell, starting at 0ºE, 90ºN. However, the assumption in the netCDF conversion was that the grid points were at the centre of each grid cell.
The resulting error in the EGM2008 geoid can be up to ±46 cm depending on the location, as shown here:
Unfortunately, the same error slipped into RADS as well.
Thus the field
geoid_egm2008is to be replaced on all missions: