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 4D-Var applications

      /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)