A Study of Sea Ice Topography in the Weddell and Ross Seas Using Dual Polarimetric TanDEM-X Imagery

• Main Authors: Huang, Lanqing, Hajnsek, Irena
• Format: Text
• Language: English
• Published: 2024
• Subjects: Antarctic; The Antarctic; Ross Sea; Weddell; Antarc*; Sea ice
• Online Access: https://doi.org/10.5194/egusphere-2023-2954; https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2954/

The sea ice topography is essential for understanding the interactions within the air-ocean-ice system. Single-pass interferometric synthetic aperture radar (InSAR) allows for the generation of digital elevation model (DEM) over the drift sea ice. However, accurate sea ice DEMs (i.e., snow freeboard) derived from InSAR are impeded due to the radar signals penetrating the snow and ice layers. This research introduces a novel methodology for retrieving sea ice DEMs using dual-polarization interferometric SAR images, considering the variation in radar penetration bias across multiple ice types. The accuracy of the method is verified through photogrammetric measurements, demonstrating the derived DEM with a root-mean-square error of 0.26 m over a 200 x 19 km area. The method is further applied to broader regions in the Weddell and the Ross Sea, offering new insights into the regional variations of sea ice topography in the Antarctic. We also characterize the non-Gaussian statistical behavior of sea ice elevations using log-normal and exponential-normal distributions. The results suggest that the exponential-normal distribution is superior in the thicker sea ice region (average elevation >0.5 m, whereas the two distributions exhibit similar performance in the thinner ice region (average elevation <0.5 m). These findings offer an in-depth representation of sea ice elevation and roughness in the Weddell and Ross Sea, which can be conducted in time series data to comprehend sea ice dynamics, including its growth and deformation.