4DVar Tutorial Introduction

4-Dimensional Variational (4D-Var) Data Assimilation Tutorial

This page is under construction

Download the code

All of the additional scripts necessary to run the 4D-Var tests are available from the ROMS Subversion (SVN) repository. The 4D-Var test cases are for the California Current System, 1/3 degree resolution, (WC13).

> svn checkout --username joeroms https://www.myroms.org/svn/src/test my_test

Directory Structure

When the checkout is complete, you will have the following directory structure under your my_test directory.

/WC13 Main California Current System application

      /ARRAY_MODES              Stabilized representer matrix array modes and clipping
      /Data                     Input data directory
      /Functionals              Analytical expression header file
      /I4DVAR                   Primal form of incremental, strong constraint 4D-Var, I4D-Var
      /I4DVAR_impact            I4D-Var observation impact
      /Normalization            4D-Var error covariance normalization coefficients
      /plotting                 4D-Var plotting scripts (Matlab and ROMS plotting package)
      /PSAS                     Dual form of 4D-Var, Physical-space Statistical Analysis System, 4D-PSAS
      /PSAS_impact              4D-PSAS observation impact
      /PSAS_sensitivity         4D-PSAS observation sensitivity (adjoint of 4D-PSAS)
      /R4DVAR                   Dual form of 4D-Var, indirect representer method, R4D-Var
      /R4DVAR_impact            R4D-Var observation impact
      /R4DVAR_sensitivity       R4D-Var observation sensitivity (adjoint of R4D-Var)