1315 / 2019-08-09 11:35:52

Satellite gravimetry and its application to cryospheric researches

15、冰冻圈科学 > 专题11：山地冰川、极地冰盖的物质平衡与动力学

The Greenland Ice Sheet (GrIS) is currently losing mass, as a result of complex mechanisms of ice-climate interactions that need to be better understood for robust estimates of future sea level rise. Here, we combine data from the satellite gravimetry mission GRACE, surface mass balance (SMB) data from modeling, and ice discharge estimates to systematically analyze the mass budget of the GrIS at various temporal and spatial scales. This study suggests the existence of a substantial seasonal meltwater storage (~100±20 Gt), which is in line with earlier qualitative observations. Meltwater storage is particularly intense in the northern, northwestern and southeastern parts of GrIS. Analysis of seasonal variations in the outlet glacier velocities shows that the contribution of ice discharge to the observed signal is minor (at the level of only a few Gt). In addition, we propose a simple way to use GRACE data for validating SMB estimates in winter, based on the fact that ice discharge cannot be negative. Our method and results can be used in support of future work on GrIS hydrology, glacier dynamics, surface mass balance, and their mutual interactions.