Retrieval of Sea Ice Drift From the Central Arctic to the Fram Strait Based on Sequential Sentinel-1 SAR Data

Abstract

Sea ice drift (SID) is crucial for understanding sea ice dynamics and for navigation safety. This study focuses on a comprehensive analysis of SID retrieval in the Arctic based on spaceborne synthetic aperture radar (SAR) data. A state-of-the-art method combining feature tracking and pattern matching techniques was applied to sequential Sentinel-1 (S1) SAR data in 2020 to derive SID from the central Arctic to the Fram Strait. The SAR retrievals were validated with drifting buoys. For temporal intervals of S1 data of approximately 24 hours, 15,254 collocations were collected from January to June and from October to December, yielding a 0.00 cm/s bias for the drift velocity magnitude and 0.27 degrees for direction with corresponding root mean square error (RMSE) of 0.47 cm/s and 4.73 degrees. Using temporal intervals of S1 data of less than 24 hours, we retrieved SID from July to September. A total of 644 collocations yields a comparison with a bias of 0.52 cm/s and 4.62 degrees for the drift magnitude and direction, respectively. The corresponding RMSE values are 1.85 cm/s and 20.73 degrees. The comparisons demonstrate better performance than the operational SAR-based SID product using the MCC method and are consistent with seasonal trends in drift velocity with the coarse-resolution product. We also analyzed the variations in SAR retrievals and further estimated appropriate temporal intervals, making it feasible to conduct long-term SID retrievals based on spaceborne SAR data at high spatial resolution in the Arctic.