Mapping icebergs in sea ice: An analysis of seasonal SAR backscatter at C- and L-band

Abstract

Icebergs in the Arctic can pose a threat to maritime traffic and offshore installations and influence the properties of the upper ocean layer. While icebergs in open water are regularly monitored using C-band SAR satellites, less attention has been paid to icebergs in regions with a high areal fraction of sea ice, where detection using traditional methods is more difficult. In this study, we compare the capability of C- and L-band SAR to detect icebergs in level and deformed fast sea ice across various seasons. To this end we use a timeseries of SAR images acquired at HH- and HV-polarization in 2019 and 2020, covering respectively 301 and 356 icebergs. As reference data for validation, we used iceberg polygons derived from Sentinel-2 images. Our results reveal that compared to C-band, L-band SAR is significantly better at separating the backscatter of icebergs and sea ice and thus is preferable for detecting icebergs in ocean regions with a high sea ice concentration. It is further shown that L-band SAR is less affected by melting conditions, suggesting that it can be used for iceberg detections in both summer and winter.