| Résumé | A iceberg drift model has been formulated for eventual operational implementation at the Canadian Ice Serivce. The model includes air and water drag forces, water pressure gradient, wave radiation stress and the effect of added mass. Besides some refinements to these parameterizations, key new features include forcing by predictive ocean model, an iceberg geometry parametrization, an implicit solution to the iceberg equation of motion and iceberg calving. The model is validated against a dataset of 17 observed iceberg drift tracks. The absolute error in predicted position icreases with the forecast duration at a rate of 12 km per day while the error relative to the observed track length decreases with forecast interval. The new model reduces drift errors over existing operational models by up to 35% at 96 hour forecast periods. The improved ocean drag forces, including both currents and iceberg profile, are the most likely source of these improvements. The effect of wave radiation stress is estimated to explain up to 10% of the iceberg drift. |
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