HINDCASTING ICEBERG DRIFT USING CURRENT PROFILES AND WINDS

A dynamic model that hindcasts iceberg drift trajectories under the in fluence of wind and current drag and Coriolis forcing is tested with d ata on winds, current profiles, and iceberg size and shape. Thirteen d rift track data sets have been compiled at 10 minute intervals for per iods of 11 to 73 hours. Icebergs were tracked by radar range and beari ng to a ship positioned by LORAN C. Sonar profiles and photographs wer e analysed to estimate iceberg mass and cross-sectional areas below an d above water. Current profiles were continuously monitored by an acou stic Doppler current profiler, and winds by an anemometer on a bow mas t. Using these data, the model is able to accurately hindcast iceberg tracks. From sensitivity tests of the relative importance of various t erms in the force balance of the model, data needs for forecasts are i nferred.