Ice lead orientation characteristics in the winter Beaufort Sea

The directional orientations of leads in the winter ice pack of the Beaufort Sea are studied both spatially and temporally. Data from the European Earth Resources Satellite-1 (ERS-1) synthetic aperture radar (SAR) was used. The SAR data was produced in image form at the Alaska SAR Facility (ASF) with 100m×100m pixel resolution. The lead ice pixels, which included all non-multiyear ice; were defined using a simple thresholding of the radar backscatter values. The orientations of the leads covering the Beaufort Sea during the period of January through March of 1992 were derived using a lead skeletonization technique. Results show a strong temporal persistence in the distribution and orientation of the leads during this period. The orientation of leads newly-formed within a 3-day period were then compared to both the local and large-scale ice deformation fields. Results show a consistent relationship between the orientations of the newly-formed leads and the principal direction of shear within the ice motion fields