In the operational application at FNMOC, NAVDAS is run with COAMPS for a fixed number of operational areas, which are scheduled to run after the boundary conditions are generated by the current run of the global NOGAPS weather forecast model. When running with COAMPS-OS at local and remote sites, a more robust on-demand procedure is needed, where the most up-to date and complete set of NOGAPS boundary conditions that can be obtained at the site are used. To support hourly analyses, the existing aircraft and satellite wind quality control procedures are being adapted to process these observations hourly. In addition, conventional surface and upper air radiosonde observations, aircraft temperature observations, NESDIS satellite temperature retrievals, and SSM/I surface marine winds speeds are utilized. When running NAVDAS with the nested-grid COAMPS model, innovations (observation-background) are obtained by successively interpolating the forecast fields to the observation locations and subtracting the result from the observations for each of the successively finer grid meshes. At the end of the procedure each observation innovation is therefore computed from the highest resolution background forecast available. An analysis grid is constructed by removing any duplicate grid points from the COAMPS grid meshes. Following the analysis, the analysis corrections are added back to each background grid to provide the initial conditions for the next forecast run. An additional correction is added to the outer grid meshes to account for differences between the background forecasts on the grid meshes.
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