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| Titel |
The sub-ice platelet layer and its influence on freeboard to thickness conversion of Antarctic sea ice |
| VerfasserIn |
D. Price, W. Rack, P. J. Langhorne, C. Haas, G. Leonard, K. Barnsdale |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 3 ; Nr. 8, no. 3 (2014-06-11), S.1031-1039 |
| Datensatznummer |
250116164
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| Publikation (Nr.) |
 copernicus.org/tc-8-1031-2014.pdf |
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| Zusammenfassung |
| This is an investigation to quantify the influence of the sub-ice platelet
layer on satellite measurements of total freeboard and their conversion to
thickness of Antarctic sea ice. The sub-ice platelet layer forms as a result
of the seaward advection of supercooled ice shelf water from beneath ice
shelves. This ice shelf water provides an oceanic heat sink promoting the
formation of platelet crystals which accumulate at the sea ice–ocean
interface. The build-up of this porous layer increases sea ice freeboard,
and if not accounted for, leads to overestimates of sea ice thickness from
surface elevation measurements. In order to quantify this buoyant effect,
the solid fraction of the sub-ice platelet layer must be estimated. An
extensive in situ data set measured in 2011 in McMurdo Sound in the
southwestern Ross Sea is used to achieve this. We use drill-hole
measurements and the hydrostatic equilibrium assumption to estimate a mean
value for the solid fraction of this sub-ice platelet layer of 0.16. This is
highly dependent upon the uncertainty in sea ice density. We test this value
with independent Global Navigation Satellite System (GNSS) surface elevation
data to estimate sea ice thickness. We find that sea ice thickness can be
overestimated by up to 19%, with a mean deviation of 12% as a result
of the influence of the sub-ice platelet layer. It is concluded that within
100 km of an ice shelf this influence might need to be considered when
undertaking sea ice thickness investigations using remote sensing surface
elevation measurements. |
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