X- and C-Band SAR Signatures of Sea Ice in the Bohai Sea

This study carried out an X- and C-band spaceborne synthetic aperture radar (SAR) observation synchronized with the field experiment in the Bohai Sea of China in January 2024. Based on the co-located X- and C-band SAR multipolarized data from TerraSAR-X/TanDEM-X, Gaofen-3, and Sentinel-1, we elucidated the signatures of thin ice and quantified their separability. Underlying the identified thin ice information, we further demonstrated the feasibility of separating thin ice and seawater from the ice-water mixture. Combining with the LiDAR-measured surface roughness, we investigated its correlation with different X- and C-band SAR signatures, of which the optimal parameter was used to develop the regression models for estimating thin ice surface roughness. The comprehensive application of multiband, multipolarization SAR contributes to resolve the ambiguity of observed thin ice signatures. Our case study highlights the potential role of multipolarized (or even fully polarized) X-band SAR for thin ice observations.