For Bolch, the different measurement values depend on the amounts of meltwater that remain on the plateau and do not flow away into the sea — and which his team has now managed to measure accurately for the first time. (sciencedaily.com)
Each original measurement value is then divided by the appropriate chronology value for that year to produce a first set of «signal - free» measurements. (link.springer.com)
The trick: the measurement values were not correlated with the actual trajectory of the satellite; instead, they were converted into two reference ellipsoids. (sciencedaily.com)