A Nested-Grid Ocean Circulation Model for Simulating Three-Dimensional Circulation and Hydrography over Canadian Atlantic Coastal Waters

A one-way nested-grid coastal ocean circulation modeling system was developed for Canadian Atlantic coastal waters based on an operational prototype shelf circulation forecast system known as Dalcoast3 and a high-resolution coastal circulation model developed for Lunenburg Bay (LB) of Nova Scotia. The nested-grid system consists of five relocatable downscaling sub-models, including the outermost sub-model covering the eastern Canadian shelf with a coarse horizontal resolution of 1/12°, and the innermost sub-model covering LB with a fine resolution of about 180 m. The nested-grid system is driven by meteorological forcing converted from three-hourly weather forecast fields provided by the Meteorological Service of Canada and tidal forcing produced by WebTide using pre-calculated tidal harmonic constants. The nested-grid system is used to simulate the dynamic response of coastal waters over the inner Scotian Shelf in June and July 2006. A comparison of model results with observations made in LB demonstrates that the NCOPS-LB performs reasonably well in simulating sea surface elevations and tidal currents, and less well in simulating hydrography and non-tidal currents over the inner shelf.