|Fig. 1 World Wide Sea Level Histories|
That PSMSL data is already syncronized by the "REVISED LOCAL REFERENCE" technique which aligns values to a common reference (RLR).
Thus, one only has to syncronize the Gloabal Mean Satellite Data (GMSD) to the already synchronized PSMSL RLR data gathered from tide gauge stations around the world (Fig. 1).
In Fig. 3 and Fig. 4 the graphs show that the satellite record is less comprehensive, having only been active since 1993.
The main thing to remember is that the tide gauge station records and the satellite records are designed for different purposes.
The satellite record is designed to show a global mean average, a generally fictitious notion, which does little to help local port jurisdictions design their particular song and dance with which they hope to cope with the incessantly rising seas.
The satellite record does next to nothing to tell them how much they individually will have to do to react to the amount of sea level change in their part of the world.
Billions are spent on the satellite records, but very little by comparison is spent on the tide gauge station systems.
Modern technology is fine and dandy, however, in the context of sea level history and future in particular locations, it is not as good as the tide gauge station system IMO.