High resolution sea ice drift and deformation off the North Coast of Greenland in March 2018

High resolution sea ice drift and deformation fields in March 2018 in the Wandel Sea and adjacent Arctic Ocean are presented. The fields cover a 30 days period of strong deformation of young ice that had formed in a preceding polynya event. Drift fields were obtained from Sentinel-1, HH polarization SAR images acquired in enhanced wide mode. These had a pixel resolution of 50 m in Polar Stereographic North projection (latitude of true scale: 70 N, center longitude: 45 W). We used an ice tracking algorithm introduced by Thomas et al. (2008, 2011) and modified by Hollands and Dierking (2011) to derive drift from sequential pairs. Based on satellite data coverage, the time steps between two scenes varied between 0.9 and 2 days. The resulting drift data set was defined on a regular grid with a spatial resolution of 700 m. Outliers in the velocity data were reduced by a 3x3 point running median filter covering an area of 2.1x2.1 km. For the deformation estimates, we calculated deformation using a linear approximation based on Green's Theorem that relates the double integral over a plane to the line integral along a simple curve surrounding the plane. We discretized the curve applying the trapezoid method that linearly interpolates velocity between the vertices of the grid cells.