Near-coastal circum-Antarctic iceberg size distributions determined from Synthetic Aperture Radar images


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Christine.Wesche [ at ] awi.de

Abstract

The Radarsat-1 Antarctic Mapping Project (RAMP) compiled a mosaic of Antarctica and the adjacent ocean zone frommore than 3000 high-resolution Synthetic Aperture Radar (SAR) images acquired in September andOctober 1997. The mosaic with a pixel size of 100 m was used to determine iceberg size distributions around Antarctica, combining an automated detection with a visual control of all icebergs larger than 5 km2 and correction of recognized false detections. For icebergs below 5 km2 in size, the numbers of false detections and accuracies of size retrievals were analyzed for three test sites. Nearly 7000 icebergs with horizontal areas between 0.3 and 4717.7 km2 were identified in a near-coastal zone of varying width between 20 and 300 km. The spatial distributions of icebergs around Antarctica were calculated for zonal segments of 20° angular width and related to the types of the calving fronts in the respective section. Results reveal that regional variations of the size distributions cannot be neglected. The highest ice mass accumulations were found at positions of giant icebergs (>18.5 km) but also in front of ice shelves from which larger numbers of smaller icebergs calve almost continuously. Although the coastal oceanic zone covered by RAMP is too narrow compared to the spatial coverage needed for oceanographic research, this study nevertheless demonstrates the usefulness of SAR images for iceberg research and the need for repeated data acquisitions extending ocean-wards over distances of 500 km and more from the coast to monitor iceberg melt and disintegration and the related freshwater input into the ocean.



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ISI/Scopus peer-reviewed
Publication Status
Published
Eprint ID
36717
DOI 10.1016/j.rse.2014.10.025

Cite as
Wesche, C. and Dierking, W. (2015): Near-coastal circum-Antarctic iceberg size distributions determined from Synthetic Aperture Radar images , Remote Sensing of Environment, 156 , pp. 561-569 . doi: 10.1016/j.rse.2014.10.025


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