Continuity of the Mass Loss of the World's Glaciers and Ice Caps From the GRACE and GRACE Follow-On Missions

We use time series of time-variable gravity from the Gravitational Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) missions to evaluate the mass balance of the world's glaciers and ice caps (GIC) for the time period April 2002 to September 2019, excluding Antarctica and Greenland peripheral glaciers. We demonstrate continuity of the mass balance record across the GRACE/GRACE-FO data gap using independent data from the GMAO Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) reanalysis. We report an average mass loss of 281.5 +/- 30 Gt/yr, an acceleration of 50 +/- 20 Gt/yr per decade, and a 13-mm cumulative sea level rise for the analyzed period. Seven regions dominate the mass loss, with the largest share from the Arctic: Alaska (72.5 +/- 8 Gt/yr), Canadian Arctic Archipelago (73.0 +/- 9 Gt/yr), Southern Andes (30.4 +/- 13 Gt/yr), High Mountain Asia (HMA) (28.8 +/- 11 Gt/yr), Russian Arctic (20.2 +/- 6 Gt/yr), Iceland (15.9 +/- 4 Gt/yr), and Svalbard (12.1 +/- 4 Gt/yr). At the regional level, the analysis of acceleration is complicated by a strong interannual to decadal variability in mass balance that is well reproduced by the GRACE-calibrated MERRA-2 data.