Remote Sensing: A Method to Improve High-Resolution Sea Ice Drift Retrievals in the Presence of Deformation Zones.
Wolfgang Dierking and his colleague Jakob Griebel from the Alfred Wegener Institute (AWI) published a paper in “Remote Sensing” on the improved detection of narrow deformation structures in sea ice (with Jakob as first author). The major idea is to avoid blurring of discontinuities in the field of sea ice drift.
Retrievals of sea ice drift from synthetic aperture radar (SAR) images at high spatial resolution are valuable for understanding kinematic behavior and deformation processes of the ice at different spatial scales. Ice deformation causes temporal changes in patterns observed in sequences of SAR images; which makes it difficult to retrieve ice displacement with algorithms based on correlation and feature identification techniques. Here, we propose two extensions to a pattern matching algorithm, with the objective to improve the reliability of the retrieved sea ice drift field at spatial resolutions of a few hundred meters. Firstly, we extended a reliability assessment proposed in an earlier study, which is based on analyzing texture and correlation parameters of SAR image pairs, with the aim to reject unreliable pattern matches. The second step is specifically adapted to the presence of deformation features to avoid the erasing of discontinuities in the drift field. We suggest an adapted detection scheme that identifies linear deformation features (LDFs) in the drift vector field, and detects and replaces outliers after considering the presence of such LDFs in their neighborhood. We validate the improvement of our pattern matching algorithm by comparing the automatically retrieved drift to manually derived reference data for three SAR scenes acquired over different sea ice covered regions.
Griebel, J.; Dierking, W. (2017): A Method to Improve High-Resolution Sea Ice Drift Retrievals in the Presence of Deformation Zones. Remote Sensing 2017, 9, 718. doi:10.3390/rs9070718 [open access]