HR: 14:40h
AN: C23B-05    [Abstracts]
TI: Antarctic Sea Ice Thickness from Passive Microwave Retrievals of Snow Depth
AU: * Maksym, T
EM: emak@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom
AU: Markus, T
EM: thortsen.markus@nasa.gov
AF: NASA Goddard Space Flight Center, Code 614.6, Greenbelt, MD 20771, United States
AB: Antarctic sea ice thickness retrievals from satellite altimeters are critically dependent on accurate estimates of snow depth, particularly so because of the relatively high snow loads and thin ice. We assess the accuracy of passive microwave estimates of snow depth and their utility for ice thickness determination by comparison with shipboard observations. Using a simple model of snow depth evolution, the predicted occurrence of snow-to-ice conversion is used as a proxy indicator for near-zero freeboard, allowing the possibility of sea-ice thickness estimation directly from satellite snow depth retrievals. The satellite data provide a good indicator of snow depth over broad scales in most cases and for all areas except for the East Antarctic sector. Using a modified algorithm for satellite snow-depth retrieval, we show that satellite snow depth can provide reasonable estimates of regionally-averaged ice thicknesses. Moreover, expected errors are likely to be less than those for altimetric methods. However, there is significant variability in the passive microwave snow depth signatures, both spatially and temporally, such that the uncertainty in ice thickness determination is comparable to the observed regional and interannual variability. This highlights the need for assimilation of models of snow-cover evolution to reduce uncertainty in satellite snow-depth retrievals.
DE: 0736 Snow (1827, 1863)
DE: 0750 Sea ice (4540)
DE: 0758 Remote sensing
SC: Cryosphere [C]
MN: 2007 Fall Meeting