ROMS/TOMS Developers

Algorithms Update Web Log

arango - August 24, 2006 @ 15:45
Sequential 4DVAR- Comments (0)

I made a couple of changes to the code to allow real-time sequential assimilation with the incremental 4DVAR algorithm (IS4DVAR):

  • Added a generic csh script, Bin/, to carry out sequential 4DVAR experiments. That is, the state estimation is split in several assimilation cycles (time windows) as new data becomes available. This script runs both the IS4DVAR algorithm and nonlinear model. It initializes the nonlinear model with the estimated optimal initial conditions from the assimilation cycle. The nonlinear model is run to end of the assimilation cycle and then the restart file becomes the first guess (background state) for the next assimilation cycle. The user needs to have the following directory structure:
         $MYROOT/                    root directory
                /Data                Application configuration Input NetCDF files
                /Forward             Nonlinear model working directory
                /IS4DVAR             Data assimilation working directory
                /OBS                 Observations NetCDF file
                /Storage             Storage directory for estimation output NetCDF files

    See above script for more details. This script is generic and well documented.

  • Removed the writing of the cost function information to the nonlinear and tangent linear initial conditions NetCDF files. This allows to use the restart file in sequential data assimilation. The diagnostic cost function information is still written to the MODname NetCDF file. This also cleaned the initial conditions files used in the 4DVAR algorithms. Therefore, the following files were changed def_ini.F, tl_def_ini.F, wrt_ini.F, and tl_write_ini.F.
  • Modified inp_par.F to write horizontal and vertical convolution stability paramenters Hgamma and Vgamma to standard output.
For the current updated file list .

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