A New Estimate of Marine Ice Accretion Under Amery Ice Shelf
Abstract
Introduction
Accreted marine ice is present under East Antarctica's Amery Ice Shelf (AIS). The distribution of marine ice under the AIS was previously mapped by Fricker et al. (2001) using Russian airborne ice-penetrating radar (IPR) measurements acquired between 1986 and 1995 and a DEM of the ice shelf surface generated from ERS-1 data. Here, we present a new estimate of accreted marine ice thickness under the outer AIS, derived from IPR measurements and laser ranging data collected jointly by China, Australia, and the US during the 2016-2017 and 2017-2018 austral summers. We hypothesize that both the distribution and properties of the marine ice layer are a signal of ocean forcing beneath the ice shelf and can be resolved using IPR measurements of the meteoric-marine ice interface. Conditions at the ice-ocean interface, including the presence of marine ice, makes AIS a compelling analog for Jupiter's icy moon, Europa. Methods We follow the approach of Fricker et al. (2001) to estimate the distribution of marine ice by applying the hydrostatic equation. Ellipsoid height is obtained using aircraft GPS elevation and laser ranging data. To obtain orthometric height, the geoid height is subtracted from the ellipsoid height. The orthometric height is then compared to the height calculated using the ice thickness from IPR data and the modeled densities of meteoric ice and sea water. The densities come from the density model described in Fricker et al. (2001). The difference between the orthometric height and IPR-derived height is called the hydrostatic height anomaly. Where the hydrostatic height anomaly is high, we expect the ice to be grounded or for marine present. Where marine ice is present, we use the orthometric height with a new density model that accounts for the presence of marine ice, to estimate the total ice thickness. The difference between the IPR-derived thickness and the revised total ice thickness gives an estimate of the thickness of marine ice.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMED41D1128M
- Keywords:
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- 0805 Elementary and secondary education;
- EDUCATIONDE: 0815 Informal education;
- EDUCATIONDE: 0855 Diversity;
- EDUCATION