Validation of synthetic aperture radar for iceberg detection in sea ice

Abstract

SAR satellites can detect icebergs over very large areas in all weather, regardless of ambient conditions like darkness, rain, and fog. As a result, SAR satellites are currently being used on the Grand Banks to enhance iceberg surveillance. During the iceberg season, the Grand Banks region is also frequented by sea ice, which is known to degrade radar performance. To quantify this performance, a validation of the iceberg detection capabilities of satellite radar in sea ice conditions was conducted. The satellite radars used in this validation process were RADARSAT-1 synthetic aperture radar (SAR) and ENVISAT advanced synthetic aperture radar (ASAR). Several sources have documented average radar signature backscatter values for various sea ice types in microwave radar imagery. As part of the validation effort discussed here, sea ice backscatter values were extracted from RADARSAT-1 SAR and ENVTSAT ASAR data and validated against these documented values. Iceberg data for various iceberg sizes have also been extracted from data for both satellites. Using the sea ice backscatter values and the iceberg data information, probability of detection (POD) curves were generated for small, medium and large sized icebergs in multiyear ice, first-year ice, thin lead ice and typical ice conditions found on the Grand Banks. This work was performed with the support of the European Space Agency (ESA), the Canadian Ice Service (CIS) and a consortium of oil and gas companies off the east coast of Newfoundland