The bathymetric and subglacial hydrological context for basal melting of the West Ice Shelf in East Antarctica
Abstract
The future fate of the Antarctic Ice Sheet under a warming climate is dynamically tied to geometric changes of the floating ice shelves due to their role in buttressing grounded ice. As Antarctic ice shelves are known to be thinning at increasing rates, their buttressing potential is expected to decrease. West Ice Shelf (WIS), located along the Leopold and Astrid Coast (LAC) in East Antarctica, is one of the least sampled large ice shelves in Antarctica. The WIS is one of the most northern ice shelves outside the Antarctic Peninsula and is located close to the continental shelf break, making it naturally vulnerable to warm atmospheric and oceanic heat delivery. Recent work suggests that deep canyons under the adjoining ice sheet likely directs subglacial meltwater across the WIS grounding line. Between 2012 and 2018 the International Collaborative Exploration of the Cryosphere through Aerogeophysical Profiling (ICECAP) project acquired a regular grid of airborne radar sounding, gravity, magnetics, and laser surface altimetry data throughout the LAC, extending from the interior of Princess Elizabeth Land, through the grounding zone, over the the WIS, and into the inner continental shelf region. The WIS geophysical surveys aimed to investigate the response of ice-shelf basal melt rates to changes in the underlying ocean and changes from upstream subglacial hydrological discharge. Here we perform airborne gravity data inversion using a geological model constrained by depth to basement solutions from airborne magnetics data. The inversion reveals seafloor troughs that may be deep enough to allow modified Circumpolar Deep Water to reach the grounding line. Our results show a new bathymetry under WIS, which we compare to other published ice shelf bathymetry in the region. The bed topography from radar data shows pathways for subglacial discharge to flow from the interior coastal basin toward the coast. We place these new observations in the context of the latest estimates of ice shelf basal melt rates. This study is the first step towards a more quantitative understanding of WIS sensitivity. A similar approach can be applied to other large ice shelves in Antarctica in the future.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C21C1355W
- Keywords:
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- 0720 Glaciers;
- CRYOSPHEREDE: 0726 Ice sheets;
- CRYOSPHEREDE: 0728 Ice shelves;
- CRYOSPHEREDE: 4207 Arctic and Antarctic oceanography;
- OCEANOGRAPHY: GENERAL