Airborne mapping of the sub-ice platelet layer under fast ice in McMurdo Sound, Antarctica
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Published:2021-01-19
Issue:1
Volume:15
Page:247-264
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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:
Haas ChristianORCID, Langhorne Patricia J.ORCID, Rack WolfgangORCID, Leonard Greg H., Brett Gemma M.ORCID, Price DanielORCID, Beckers Justin F.ORCID, Gough Alex J.
Abstract
Abstract. Basal melting of ice shelves can result in the outflow of
supercooled ice shelf water, which can lead to the formation of a sub-ice
platelet layer (SIPL) below adjacent sea ice. McMurdo Sound, located in the
southern Ross Sea, Antarctica, is well known for the occurrence of a SIPL
linked to ice shelf water outflow from under the McMurdo Ice Shelf.
Airborne, single-frequency, frequency-domain electromagnetic induction (AEM)
surveys were performed in November of 2009, 2011, 2013, 2016, and 2017 to
map the thickness and spatial distribution of the landfast sea ice and
underlying porous SIPL. We developed a simple method to retrieve the
thickness of the consolidated ice and SIPL from the EM in-phase and
quadrature components, supported by EM forward modelling and calibrated and
validated by drill-hole measurements. Linear regression of EM in-phase
measurements of apparent SIPL thickness and drill-hole measurements of
“true” SIPL thickness yields a scaling factor of 0.3 to 0.4 and rms error
of 0.47 m. EM forward modelling suggests that this corresponds to SIPL
conductivities between 900 and 1800 mS m−1, with associated SIPL solid
fractions between 0.09 and 0.47. The AEM surveys showed the spatial
distribution and thickness of the SIPL well, with SIPL thicknesses of up to
8 m near the ice shelf front. They indicate interannual SIPL thickness
variability of up to 2 m. In addition, they reveal high-resolution spatial
information about the small-scale SIPL thickness variability and indicate
the presence of persistent peaks in SIPL thickness that may be linked to the
geometry of the outflow from under the ice shelf.
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference50 articles.
1. Archie, G. E.: The electrical resistivity log as an aid in determining some reservoir characteristics, Trans. Am. Inst. Min. Metall. Petr. Eng., 146, 54–62, 1942. 2. Barry, J. P.: Hydrographic patterns in McMurdo Sound, Antarctica and their
relationship to local benthic communities, Polar Biol., 8, 377–391,
https://doi.org/10.1007/BF00442029, 1988. 3. Brett, G. M., Irvin, A., Rack, W., Haas, C., Langhorne, P. J., and Leonard, G. H.: Variability in the distribution of fast ice and the sub-ice platelet
layer near McMurdo Ice Shelf, J. Geophys. Res.-Oceans, 125, e2019JC015678, https://doi.org/10.1029/2019JC015678, 2020. 4. Brunt, K. M., Sergienko, O., and MacAyeal, D. R.: Observations of unusual
fast-ice conditions in the southwest Ross Sea, Antarctica: preliminary
analysis of iceberg and storminess effects, Ann. Glaciol., 44, 183–118, 2006. 5. Campbell, S., Courville, Z., Sinclair, S., and Wilner, J.: Brine, englacial
structure and basal properties near the terminus of McMurdo Ice Shelf,
Antarctica, Ann. Glaciol., 58, 1–11, https://doi.org/10.1017/aog.2017.26, 2017.
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