Wind stress, water drag, and Coriolis force were assumed to be at equilibrium for a drifting group. Surface wind speed and ice motion velocity were obtained from three-day sequences of surface weather charts and Landsat-1 MSS images. The angle of sea-ice deflection, the cross-isobar angle, sea-ice thickness, and the surface and sub-surface drag coefficients were determined by solving the equilibrium equation of motion. Weather data from a fourth day were used to predict the motions for this day.
If used in conjunction with data from microwave sensing systems, these predictions and parameters could be applied to support marine traffic and exploration of natural resources in the Polar Oceans. Sea-ice parameters, which were formerly practically unavailable, can now be derived by the method.
Discussion
O. H. Løken: To what extent are the results of your study being used in the preparation of operational ice forecasts for the Beaufort Sea?
U. Feldman: This method is not yet operational because the MSS images of Landsat-1 provide useful data only if the images are cloud free. The method may be applied in the future with remotely-sensed data from microwave systems.
J. B. Mercer: How many tests of your method have you made? You mentioned two in your talk. What is the success rate?
Feldman: Out of approximately 3000 Landsat-1 MSS images recorded during the period 1972–76 over the study area, 35 images, belonging to 6 cycles, were found suitable for analysis. From the 6 cycles tested 4 were successful.