Implementation of Grid Nesting: a first look with grid mosaics

John C. Warner (1) and Hernan G. Arango (2)

(1) US Geological Survey, Woods Hole, MA
(2) Institute of Marine and Coastal Sciences, Rutgers-The State University of New Jersey, New Brunswick, NJ

The nature of a single rectilinear grid provides limited flexibility to easily allow localized regions of increased resolution or local regions of grid curvature to follow topography or bathymetric features. To facilitate these abilities, we are investigating a methodology to implement grid nesting capabilities into ROMS. Grid nesting covers several types of grid assemblages: (1) grid mosaics which connect several grids along their edges, (2) grid refinement which provides increased resolution in a specific region, and (3) composite grids which allow overlap regions of non-aligned grids.

We will describe the current implementation of grid nesting by focusing on applications of grid mosaics. Exchanges are achieved by redefining the grid indices and provide a means for a natural continuation of each grid to extend into the adjacent grids. We describe the method, the implementation, and provide results for a simple test case. A method for grid development is presented and the grid mosaic capabilities are demonstrated on a realistic environment of the Hudson River Estuary.