Marie Byrd Land glacier change intimately linked to inter-decadal climate variability
Abstract
Recent studies have revealed that ice along much of West Antarctica's coastline from the Antarctic Peninsula to the Ross Sea is undergoing dynamic thinning, likely in response to oceanic forcing. As part of a wider goal to understand how these forcings operate, and how they may vary in nature along West Antarctica's coastline, it is necessary to quantify indicators of dynamic thinning along the entire region, including those parts of West Antarctica that have traditionally received less attention. Here, we capture changes to the grounding-line position along coastal Marie Byrd Land, which comprises approximately 50% of West Antarctica's Pacific-facing margin, and incorporates the 650 km wide Getz Ice Shelf and the coastline stretching westwards to the Ross Ice Shelf. Changes to grounding-line position are derived over multiple epochs from optical satellite imagery. Using Landsat ETM+/OLI and ASTER L1T imagery, we derive advance and retreat values along the coastline for 3-to-5-year periods from 2000-2015. We find that: i) the grounding line fronted by Getz Ice Shelf has retreated notably over the past 15 years, in contrast with negligible change further west along Nickerson and Sulzberger Ice Shelves; and ii) there is a strong correspondence between the grounding-line retreat at Getz Ice Shelf with previously published evidence of recent glaciological change, including sustained ice thinning as detected by satellite altimetry, high ice-flow velocities and large ice-shelf melt rates. Collectively, these observations suggest that there is a regional organisation of ice, ocean and climate interaction along the Marie Byrd Land margin, wherein the timing and magnitude of glacial change varies from east to west. This hypothesis is substantiated by observations of marked variability in the offshore wind field (from ERA-interim climate reanalysis data), consistent with variability in Circumpolar Deep Water intrusion rates towards Marie Byrd Land between 2003 and 2015. Mirroring the pronounced, inter-decadal variability in ocean forcing witnessed in the neighbouring Amundsen Sector in recent years, our findings thus underscore the requirement for close observation of this important coastline in the future.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C51B0978C
- Keywords:
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- 0728 Ice shelves;
- CRYOSPHERE;
- 0746 Lakes;
- CRYOSPHERE;
- 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE