Mass Balance and Climate Drivers in the Antarctic Peninsula, a GRACE Gravity Analysis

Antarctic ice-mass balance is key to project sea-level changes, to assess future shifts in the global water cycle and ocean circulation, and to predict the fate of the White Continent. The surface mass balance is an essential component of the total ice-mass balance, with intense variations on time scales of months to decades. The surface mass balance varies spatially over Antarctica as a consequence of complex interplay between accumulation, transport and ablation. These processes respond to patterns and changes of the atmospheric and oceanic circulations which may extend far beyond Antarctica. Identifying and understanding climatic teleconnections helps improve the accuracy of ice-mass balance estimates for Antarctica and individual regions. Compared to the Antarctic Ice Sheet covering East and West Antarctica, the Antarctic Peninsula poses particular challenges for the quantification of the surface-mass balance based on regional climate models. The topography, finely structured by mountain ranges, bays and islands, fragments the ice into many individual glaciers and small drainage basins. The exposed position makes the peninsula region especially sensitive to the ocean and the atmosphere, including changes in the extrapolar circulation. During the last decades, the mass balance and dynamics of the glaciers in the Antarctic Peninsula have been affected by the break-up of ice shelves.

In our work we use GRACE and GRACE Follow-On level-2 satellite gravimetry data, provided by monthly ITSG solutions to maximum degree/order 120, to investigate whether mass variations throughout the peninsula region (61-76°S, 55-80°W, except areas corresponding to ocean or ice shelves) correlate with large‐scale climate modes as El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM), and mass balance estimates derived from regional climate models. Our analysis indicates a mass loss over two decades, mainly due to a period of enhanced mass-loss rate between 2007 and 2015. Also, our results suggest that these mass variations are primarily controlled by the surface mass balance which is influenced by the El Niño-Southern Oscillation phenomenon (ENSO).