Validation and production of RADARSAT‐1 derived ice‐motion maps in the North Water (NOW) polynya, January ‐ December 1998

Abstract

Monitoring ice motion may provide insight into the atmospheric and oceanic forces acting on ice motion and thus the mechanisms that contribute to polynya dynamics. A study of ice kinematics in the North Water (NOW) region was performed using time sequential and spatially overlapping RADARSAT‐1 ScanSAR Wide images (January to December 1998) processed by the Canadian Ice Service (CIS) Ice Tracking Algorithm (Tracker). The objectives of this research were to: 1) validate the NOW region ice motions derived using Tracker; 2) create monthly image‐maps that present ice speeds and directions over the NOW region for an entire year (January to December 1998); 3) compare these results to previous ice motion studies done in the NOW region; and 4) develop initial insights into relations between derived ice motion and latent and sensible heat mechanisms in the NOW Polynya. Tracker ice motions were validated using in situ ice beacons deployed between April and November 1998. Tracker magnitude and direction coefficients of determination (R2) were 0.93 and 0.79 respectively, with standard errors of estimate of 3.6 km in magnitude and 38.8° in direction. The monthly ice motion maps describe the annual evolution of the polynya quite accurately and compare well to other studies. High levels of ice export are found which supports the theory that winds or ocean currents continually remove ice from the polynya as it forms. A northward import of ice into the polynya along the Greenland coast shows the recycling of ice into the polynya. Evidence of oceanic (sensible) heat contributing to the open water of the polynya was not evident using the Tracker ice motion methods.