A scattering study over the Terra Nova Bay coastal polynya based on C-Band SAR measurements

The Antarctica Terra Nova Bay (TNB) coastal polynya is a highly complex and dynamic environment, for which synthetic aperture radar (SAR) observations potentially provide valuable information. However, the interpretation of SAR imagery in this environment remains challenging due to the complexity of the underlying sea ice and ocean processes. In this study, we analyze C-band Sentinel-1 SAR data to investigate the scattering mechanisms associated with different regions of the open TNB polynya during its opening phase, under low-to-moderate wind conditions. Two representative scattering scenarios are considered where visual inspection suggests to be related to dominant sea water and sea ice. The analysis is based on the improved integral equation method (IIEM), a surface scattering model that allows providing physical insights into the observed scattering processes while keeping acceptable the level of model complexity. Owing to the lack of reliable ground-truth information on the dielectric and surface roughness parameters of the scattering scenarios, the IIEM is properly calibrated. Results show a good agreement between IIEM predictions and observed backscatter over the area supposed to be dominated by sea ice, and suggest a nonnegligible presence of frazil ice over the water region supposed to be completely ice free.