Abstract

During July 2018, an expedition was carried out offshore northern Newfoundland to central Labrador to profile, track, and forecast the drift of icebergs. One of the central goals of the drift modelling work was to test potential improvements in iceberg drift forecast accuracy up to 24 hours when measured iceberg profiles are used as opposed to estimated iceberg draft and mass. During the expedition, 14 icebergs were profiled using a rapid iceberg profiling system which uses a multibeam for the underwater portion of the iceberg and a LiDAR for the freeboard. The 14 icebergs were tracked on the vessel marine radar, and their drift was forecast using a physical model which time integrates the momentum balance of the forces acting on the iceberg. The iceberg profiles were three-dimensional point clouds which provided a highly accurate representation of the iceberg dimensions and shape, and from which a volume and mass could be readily calculated. The point cloud was projected into a two-dimensional plane from 16 perspective angles and averaged into a single projection of iceberg keel and freeboard against which the currents and winds were forced in the drift model, respectively. Average results for the forecast iceberg position versus observed at 24 hours show approximately a nearly 3 km or 18% improvement when iceberg profiles are incorporated into the drift model as opposed to using estimated iceberg draft, shape, and mass. The drift model will become part of an integrated ice profiling, forecasting, and management system for oil and gas exploration and drilling operations on the Grand Banks offshore Newfoundland.

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