Analysis of regional mass balance in Antarctica using GRACE/GRACE-FO and SMB models of varying complexity.
Abstract
The Antarctic ice sheet is losing mass at an accelerating rate and contributing to sea level rise. However, there are large uncertainties in sea level rise projections due to uncertainty from representing the physical processes that are driving the ice mass changes in numerical models. In order to improve the projections, it is essential to better understand ongoing changes and better constrain models at the regional scale, which is best addressed through a suite of remote sensing observations. Here we employ GRACE and GRACE-FO satellite mission data to measure changes in Antarctic ice sheet mass balance from 2002 to the present in the George VI and Stange drainage basins of the Antarctic Peninsula, which are two sectors undergoing rapid change and with a significant potential contribution to sea level rise compared to the rest of the Peninsula. We use the gravity solutions from CSR, JPL, and GFZ, degree-1 coefficients are recovered using ocean models and degree 2 GRACE coefficients, and C20 and C30 coefficients are replaced with NASA Goddard Space Flight Center SLR estimates. We apply a 250 km Gaussian filter to smooth the harmonics. We include the latest GIA correction. We employ regional varying spherical cap mascons to extract a regional time series. We compare these results with the mass budget estimates that combine ice discharge along the grounding line of the basins with the SMB reconstructed from atmospheric regional climate models including RACMO2.3, MAR3.6, as well as NASA MERRA-2 reanalysis data. The results permit a cross-calibration of the mass balance estimates with MBM, which in turn is extended further back in time to build a longer time record. An examination of the partitioning of the mass loss between SMB and discharge indicates that these basins are dominated by the acceleration of the glaciers in response to climate forcing.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMC054.0019K
- Keywords:
-
- 0726 Ice sheets;
- CRYOSPHERE;
- 0728 Ice shelves;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 0762 Mass balance;
- CRYOSPHERE