Ice shelf basal melt rates from a high-resolution digital elevation model (DEM) record for Pine Island Glacier, Antarctica
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Published:2019-10-10
Issue:10
Volume:13
Page:2633-2656
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ISSN:1994-0424
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Container-title:The Cryosphere
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language:en
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Short-container-title:The Cryosphere
Author:
Shean David E.ORCID, Joughin Ian R., Dutrieux PierreORCID, Smith Benjamin E.ORCID, Berthier EtienneORCID
Abstract
Abstract. Ocean-induced basal melting is responsible for much of
the Amundsen Sea Embayment ice loss in recent decades, but the total
magnitude and spatiotemporal evolution of this melt is poorly constrained.
To address this problem, we generated a record of high-resolution digital
elevation models (DEMs) for Pine Island Glacier (PIG) using commercial
sub-meter satellite stereo imagery and integrated additional 2002–2015
DEM and altimetry data. We implemented a Lagrangian elevation change (Dh∕Dt)
framework to estimate ice shelf basal melt rates at 32–256 m resolution. We
describe this methodology and consider basal melt rates and elevation change
over the PIG ice shelf and lower catchment from 2008 to 2015. We document
the evolution of Eulerian elevation change (dh∕dt) and upstream propagation of
thinning signals following the end of rapid grounding line retreat around
2010. Mean full-shelf basal melt rates for the 2008–2015 period were
∼82–93 Gt yr−1, with ∼200–250 m yr−1 basal melt
rates within large channels near the grounding line, ∼10–30 m yr−1 over the main shelf, and ∼0–10 m yr−1 over the North shelf and
South shelf, with the notable exception of a small area with rates of
∼50–100 m yr−1 near the grounding line of a fast-flowing
tributary on the South shelf. The observed basal melt rates show excellent
agreement with, and provide context for, in situ basal melt-rate observations. We
also document the relative melt rates for kilometer-scale basal channels and keels
at different locations on the ice shelf and consider implications for ocean
circulation and heat content. These methods and results offer new indirect
observations of ice–ocean interaction and constraints on the processes
driving sub-shelf melting beneath vulnerable ice shelves in West Antarctica.
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
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