Heterogeneous basal melt rates under George VI ice shelf, Antarctic Peninsula
Abstract
The majority of meteoric ice that forms in Antarctica leaves the ice sheet through floating ice shelves, many of which have been thinning substantially over the last 25 years. A significant proportion of ice-shelf thinning has been driven by submarine melting facilitated by increased access of relatively warm modified Circumpolar Deep Water to sub-shelf cavities. This mass reduction is significant due to the role ice shelves play in buttressing ice sheets against unstable retreat, and it is important that the role of future ocean warming in Antarctic stability be understood. Under some ice shelves, melting is concentrated near grounding lines and along inverted channels. Numerical studies suggest that buttressing loss is sensitive to the location of ice removal within an ice-shelf. Thus it is important that we observe spatial patterns, as well as magnitudes, of ice-shelf thinning, in order to improve understanding of the ocean drivers of thinning and of their impacts on ice-shelf stability.
Glaciers feeding George VI ice shelf, Western Palmer Land, are the largest source of the current mass loss from the Antarctic Peninsula and this region is thought to be particularly sensitive to a potential collapse of George VI ice shelf due to marine ice sheet instability. George VI is also significantly affected by supra-glacial melt to the north, and by strong basal melting to the south. Here we present high-resolution maps of basal melt rates between 2010 and 2019 under the George VI ice shelf. These maps are derived from mass conservation applied to high resolution altimetry (CryoSat-2 and IceSat-2), SAR (Sentinel-1), and Optical (Landsat-8) sensors. We show that a significant proportion of the ice shelf undergoes thinning and melting along narrow regions localised near the grounding line of major glaciers feeding George VI that have been shown to accelerate in recent years. Some of these melt patterns are channelised suggesting the influence of sub-glacial related processes. Elsewhere under the shelf, melting is more subdued. We discuss implications for factors affecting basal melt patterns and for the stability of the sector.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C13A..04G
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE;
- 0728 Ice shelves;
- CRYOSPHERE;
- 4207 Arctic and Antarctic oceanography;
- OCEANOGRAPHY: GENERAL