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Boundary Conditions
The first step of implementing this ELCIRC model application at NOAA/NOS was to evaluate the model performance over a one-year period. The year 2002 was selected for a hindcast simulation, as there was a significant amount of data available for evaluating the model during this time frame. For this 2002 hindcast simulation, external model forcings included tides from a regional tide model (Myers and Baptista, 2001), oceanic temperature and salinity profiles (for nudging along the open ocean boundary) from the Navy Coastal Ocean Model (Martin, 2000), atmospheric forcing variables (for winds, pressure and heat flux) from NCEP reanalysis fields, Columbia and Willamette riverflows from USGS gauges (14128870 and 14211720, respectively), and Fraser riverflows from the Hope gauge of Environment Canada. These inputs were compiled by OHSU and transferred for implementation on NOS computers and evaluation of results.
Using the grid and numerical model parameterizations from the hindcast and tidal simulations, nowcast/forecast simulations were set up using realtime observational data and model forecasts as inputs. Nowcasts are simulations of conditions over the previous hour from the present time, and the forecasts simulate conditions 12 hours into the future. The nowcasts and forecasts both use climatological temperature and salinity values along the open ocean boundary for numerical nudging, the same tidal boundary conditions as the hindcast, atmospheric forcings from NCEP’s North American Mesoscale model, Columbia and Willamette riverflows available from NOAA’s Pacific Northwest River Forecast Center, and climatological riverflows for the Fraser River. The output from the nowcasts and forecasts are updated on a publicly available experimental webpage maintained at NOAA/CSDL. Skill assessment statistics are similarly being applied to these nowcasts and forecasts to validate the performance of the realtime model results. More information is available at http://www.csc.noaa.gov/csp
