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External influences on the Mertz Glacier Tongue (East Antarctica) in the decade leading up to its calving in 2010

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posted on 2023-05-18, 09:37 authored by Robert MassomRobert Massom, Alan Giles, Roland WarnerRoland Warner, Fricker, HA, Benoit LegresyBenoit Legresy, Glenn HylandGlenn Hyland, Lescarmontier, L, Neal YoungNeal Young
The Mertz Glacier Tongue (MGT) in East Antarctica lost ~55% of its floating length in February 2010, when it calved large tabular iceberg C28 (78 × 35 km). We analyze the behavior of the MGT over the preceding 12 years using a variety of satellite data (synthetic aperture radar and Landsat imagery and Ice, Cloud, and land Elevation Satellite laser altimetry). Contact of its northwestern tip with the eastern flank of shoals from 2002/2003 caused eastward deflection of the ice flow by up to ~47°. This change contributed to opening of a major rift system ~80 km to the south, along which iceberg C28 eventually calved. Paradoxically, the seabed contact may have also held the glacier tongue in place to delay calving by ~8 years. Our study also reveals the effects of other, more localized external influences on the MGT prior to calving. These include an abrupt sideways displacement of the glacier tongue front by at least ~145 m following an apparent collision with iceberg C08 in early 2002 and calving of numerous small icebergs from the advancing northwestern front due to the “chiseling” action of small grounded icebergs and seabed contact, resulting in the loss of ~36 km2 of ice from 2001 to 2006. The example of the MGT confirms the need for accurate bathymetry in the vicinity of ice shelves and glacier tongues and suggests that the cumulative effect of external factors might be critical to understanding and modeling calving events and ice shelf stability, necessarily on a case-specific basis.

History

Publication title

Journal of Geophysical Research: Earth Surface

Volume

120

Pagination

490-506

ISSN

2169-9003

Department/School

Institute for Marine and Antarctic Studies

Publisher

Wiley-Blackwell Publishing, Inc

Place of publication

United States

Rights statement

© 2015. Australian Antarctic Division, Commonwealth of Australia

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the earth sciences

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