High radar-backscatter regions on Antarctic sea-ice and their relation to sea-ice and snow properties and meteorological conditions |
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| Authors: | Sascha Willmes Christian Haas Marcel Nicolaus |
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| Affiliation: | 1. University of Trier, Department of Environmental Meteorology , Trier , Germany willmes@uni-trier.de;3. Alfred Wegener Institute for Polar and Marine Research , Bremerhaven , Germany;4. Department of Earth and Atmospheric Sciences , Edmonton , Canada;5. Norwegian Polar Institute , Troms? , Norway |
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| Abstract: | The temporal and spatial variability of sea-ice radar signatures in the Southern Ocean during late winter, spring and early summer from QuikSCAT data is presented. We observe a circumpolar and broad band of sea-ice close to the marginal ice zone that is characterized by very high radar backscatter. This feature is explained through detailed in situ observations of snow and sea-ice properties as well as in relation to meteorological conditions, which were derived from US National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. Our results indicate that high backscatter regions are caused by metamorphous snow, which forms through re-freezing after short-term melt events. This process is connected with the episodic passes of low-pressure systems entraining warmer air from the north. South of the Antarctic Circumpolar Trough, sea-ice is not affected by this influence and shows spatially homogenous microwave signatures with low backscatter. |
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