Comparing methods of measuring sea-ice density in the East Antarctic
Hutchings, J.; Heil, P.; Lecomte, O.; Stevens, R.; Steer, A.; Lieser, J. (2015). Comparing methods of measuring sea-ice density in the East Antarctic. Ann. Glaciol. 56(69): 77-82. https://dx.doi.org/10.3189/2015AoG69A814
In: Annals of Glaciology. International Glaciological Society: Cambridge. ISSN 0260-3055; e-ISSN 1727-5644, meer
Remotely sensed derivation of sea-ice thickness requires sea-ice density. Sea-ice density was estimated with three techniques during the second Sea Ice Physics and Ecosystem eXperiment (SIPEX-II, September–November 2012, East Antarctica). The sea ice was first-year highly deformed, mean thickness 1.2m with layers, consistent with rafting, and 6–7/10 columnar ice and 3/10 granular ice. Ice density was found to be lower than values (900–920 kgm–3 used previously to derive ice thickness, with columnar ice mean density of 870 kgm–3.At two different ice stations the mean density of the ice was 870 and 800 kgm–3, the lower density reflecting a high percentage of porous granular ice at the second station. Error estimates for mass/volume and liquid/solid water methods are presented. With 0.1m long, 0.1m core samples, the error on individual density estimates is 28 kgm–3. Errors are larger for smaller machined blocks. Errors increase to 46 kgm–3 if the liquid/solid volume method is used. The mass/volume method has a low bias due to brine drainage of at least 5%. Bulk densities estimated from ice and snow measurements along 100m transects were high, and likely unrealistic as the assumption of isostatic balance is not suitable over these length scales in deformed ice.
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