Revisiting Greenland Ice Sheet Mass Loss Observed by GRACE

In this paper we discuss a new method for determining mass
time series for 16 hydrological basins representing the Greenland system (GS)
whereby we rely on Gravity Recovery and Climate Experiment (GRACE)
mission data. In the same analysis we also considered observed mass changes
over Ellesmere Island, Baffin Island, Iceland and Svalbard (EBIS). The summed
contribution of the complete system yields a mass loss rate and acceleration
of −252±28 Gt/yr and −22±4 Gt/yr2 between March 2003 and February
2010 where the error margins follow from two glacial isostatic adjustment
(GIA) models and three processing centers providing GRACE monthly po-
tential coefficient sets. We describe the relation between mass losses in the
GS and the EBIS region and found that the uncertainties in all areas are cor-
related. The summed contribution of Ellesmere Island, Baffin Island, Iceland
and Svalbard yields a mass loss rate of −51 ± 17 Gt/yr and an accelera-
tion of −13 ± 3 Gt/yr2 between March 2003 and February 2010. The new
regional basin reconstruction method shows that the mass loss within the
southeastern basins in the GS has slowed down since 2007 while mass loss
in western basins increased showing a progression to the north of Greenland.