Three-Dimensional Hydrodynamic Model Developments for a Delaware River and Bay Nowcast/Forecast System.

摘要

The National Ocean Service (NOS) installed a Physical Oceanographic Real Time System (PORTS) during 2003 to provide water surface elevation, currents at prediction depth (4.7m below MLLW) as well as near-surface and near-bottom temperature and salinity, and meteorological information. To complement the PORTS, a new next generation nowcast/forecast system has been developed. This next generation nowcast/forecast system domain extends from the head of tide at Trenton, NJ out to the continental shelf break and is run on the National Center for Environmental Prediction (NCEP) supercomputers based on a recently developed High Performance Computing Coastal Ocean Modeling Framework (HPC-COMF; Zhang et al., 2010) to allow four times daily six-hour nowcasts and 48 hour forecasts. In conjunction with this effort, a Model Evaluation Environment (MEE) as described by Patchen (2008) was constructed for the Delaware River and Bay based on the NOS 1984-1985 Circulation Data Survey (Klavans et al., 1986). As a first step the MEE results are used to guide the development of the Delaware River and Bay Nowcast/Forecast System. First, we describe and present the results from the MEE. Based on the MEE results, the Princeton Ocean Model (POM) and the Regional Ocean Modeling System (ROMS) were selected for further application in the Delaware River and Bay and both used the same medium resolution grid. Next, POM and ROMS common medium resolution grid revised simulation results are presented, respectively, in an effort to improve upon the MEE results. To further improve results in the river sections, a new higher resolution grid using the DELFT3D-RFGRID software was constructed. To take advantage of the parallel computing opportunities at National Centers for Environmental Prediction (NCEP), ROMS was selected as the hydrodynamic model in Delaware Bay Operational Forecast System (DBOFS). ROMS high resolution grid results are presented for the two 15-day simulations as well as for an extended seven month hindcast and contrasted with the medium resolution results. The ROMS high resolution grid was used to investigate the sensitivity of the tidal response to bottom roughness coefficients and offshore tidal constituents in eighteen tidal simulations during April 1984.