Ephemeral grounding as a signal of ice-shelf change
Interferometric synthetic aperture radar (InSAR) observations of ice-shelf tidal deformation reveal the wide transition between grounded and floating ice as well as local areas where the ice shelf is only grounded at low tide, a condition that we call ephemeral grounding. Ephemeral grounding creates...
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ftcdlib:oai:escholarship.org/ark:/13030/qt2q0462j8 2023-05-15T13:52:09+02:00 Ephemeral grounding as a signal of ice-shelf change Schmeltz, M Rignot, E MacAyeal, DR 71 - 77 2001-01-01 application/pdf https://escholarship.org/uc/item/2q0462j8 unknown eScholarship, University of California qt2q0462j8 https://escholarship.org/uc/item/2q0462j8 CC-BY CC-BY Journal of Glaciology, vol 47, iss 156 Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences article 2001 ftcdlib 2021-08-30T17:10:42Z Interferometric synthetic aperture radar (InSAR) observations of ice-shelf tidal deformation reveal the wide transition between grounded and floating ice as well as local areas where the ice shelf is only grounded at low tide, a condition that we call ephemeral grounding. Ephemeral grounding creates a subtle, local disturbance on the vertical motion field of the ice-shelf surface in response to changes in occanic tide which is detected with millimetric precision using InSAR. These ice-shelf features are, however, not expected to produce a noticeable disturbance on the ice-shelf velocity field. To illustrate the influence of ephemeral grounding on ice-shelf creep flow, we use a finite-element model in which ephemeral grounding is incorporated through a variable basal friction coefficient. The results show that while ice rises (permanently grounded areas) have a pronounced influence on the ice-shelf velocity field, areas of ephemeral grounding have a vanishingly small influence. What is thus of most interest is the capacity for observations of ephemeral grounding to reveal subtle changes in ice-shelf thickness over time. We discuss an example in the Thwaites Glacier area, West Antarctica, where multi-year data show how ice rises become ephemeral grounding and subsequently disappear. This result is consistent with the grounding-line retreat and ice thinning of Thwaites Glacier. Article in Journal/Newspaper Antarc* Antarctica Ice Shelf Journal of Glaciology Thwaites Glacier West Antarctica University of California: eScholarship Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctica |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
spellingShingle |
Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences Schmeltz, M Rignot, E MacAyeal, DR Ephemeral grounding as a signal of ice-shelf change |
topic_facet |
Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
description |
Interferometric synthetic aperture radar (InSAR) observations of ice-shelf tidal deformation reveal the wide transition between grounded and floating ice as well as local areas where the ice shelf is only grounded at low tide, a condition that we call ephemeral grounding. Ephemeral grounding creates a subtle, local disturbance on the vertical motion field of the ice-shelf surface in response to changes in occanic tide which is detected with millimetric precision using InSAR. These ice-shelf features are, however, not expected to produce a noticeable disturbance on the ice-shelf velocity field. To illustrate the influence of ephemeral grounding on ice-shelf creep flow, we use a finite-element model in which ephemeral grounding is incorporated through a variable basal friction coefficient. The results show that while ice rises (permanently grounded areas) have a pronounced influence on the ice-shelf velocity field, areas of ephemeral grounding have a vanishingly small influence. What is thus of most interest is the capacity for observations of ephemeral grounding to reveal subtle changes in ice-shelf thickness over time. We discuss an example in the Thwaites Glacier area, West Antarctica, where multi-year data show how ice rises become ephemeral grounding and subsequently disappear. This result is consistent with the grounding-line retreat and ice thinning of Thwaites Glacier. |
format |
Article in Journal/Newspaper |
author |
Schmeltz, M Rignot, E MacAyeal, DR |
author_facet |
Schmeltz, M Rignot, E MacAyeal, DR |
author_sort |
Schmeltz, M |
title |
Ephemeral grounding as a signal of ice-shelf change |
title_short |
Ephemeral grounding as a signal of ice-shelf change |
title_full |
Ephemeral grounding as a signal of ice-shelf change |
title_fullStr |
Ephemeral grounding as a signal of ice-shelf change |
title_full_unstemmed |
Ephemeral grounding as a signal of ice-shelf change |
title_sort |
ephemeral grounding as a signal of ice-shelf change |
publisher |
eScholarship, University of California |
publishDate |
2001 |
url |
https://escholarship.org/uc/item/2q0462j8 |
op_coverage |
71 - 77 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Thwaites Glacier West Antarctica |
geographic_facet |
Thwaites Glacier West Antarctica |
genre |
Antarc* Antarctica Ice Shelf Journal of Glaciology Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctica Ice Shelf Journal of Glaciology Thwaites Glacier West Antarctica |
op_source |
Journal of Glaciology, vol 47, iss 156 |
op_relation |
qt2q0462j8 https://escholarship.org/uc/item/2q0462j8 |
op_rights |
CC-BY |
op_rightsnorm |
CC-BY |
_version_ |
1766256404750925824 |