Abstract: Global sea levels would rise by 7 m, if the Greenland Ice Sheet (GrIS) were to melt completely. Therefore, an accurate estimate of the mass change over the GrIS is of great importance for the understanding of the reaction of the GrIS to global climate change. Using nearly 20 years of monthly gravity field data provided by the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow On (GRACE-FO) mission, as well as satellite altimetry data from European Remote Sensing (ERS-2), Envisat, and CryoSat-2, this study comparatively analyzes the characteristics of GrIS mass change between April 2002 and December 2020. Results demonstrate that: (1) the spatial distributions of mass change trends estimated by GRACE/GRACE-FO mascon solutions and satellite altimetry data are relatively consistent; both indicate severe mass loss in the low-elevation regions around the GrIS margin and a mass accumulation in the inner plateau. (2) The mass loss of the GrIS contributed to a global mean sea level change of 0.73 ± 0.01 mm∙a⁻¹ between 2002 and 2020. (3) The southwest and northwest regions of the GrIS contributed to 43.69% of the total sea level change, making them the primary contributors to sea level rise. (4) We compared basin-scale mass change estimates from the satellite altimetry with those from mascon solutions and found that the Goddard Space Flight Center (GSFC) mascon solutions is the closest.

Key words: Greenland Ice Sheet, sea-level change, mass change, satellite gravity and altimetry, spatio-temporal characteristics