Changes between Version 15 and Version 16 of Implement3DVarAnalysisPDAF3Universal


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Timestamp:
Jun 10, 2025, 4:39:58 PM (7 days ago)
Author:
lnerger
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  • Implement3DVarAnalysisPDAF3Universal

    v15 v16  
    3737There are genenerally three different variants of 3D-Var provided by PDAF: parameterized 3D-Var, 3D Ensemble Var, and hybrid (parameterized + ensemble) 3D-Var. All can be called using the universal interface routines described here.
    3838
    39 The different 3D-Var methods in PDAF were explained on the [wiki:Implement3DVarAnalysisOverviewPDAF3 page providing the verview of the Analysis Step for 3D-Var Methods]. Depending the type of 3D-Var, the background covariance matrix '''B''' is represented either in a parameterized form, by an ensemble, or by a combination of both. The 3D-Var methods that use an ensemble need to transform the ensemble perturbations using an ensemble Kalman filter. PDAF uses for this the error-subspace transform filter ESTKF. There are two variants: The first uses the localized filter LESTKF, while the second uses the global filter ESTKF.
     39The different 3D-Var methods in PDAF were explained on the [wiki:Implement3DVarAnalysisOverviewPDAF3 page providing the overview of the Analysis Step for 3D-Var Methods]. Depending the type of 3D-Var, the background covariance matrix '''B''' is represented either in a parameterized form, by an ensemble, or by a combination of both. The 3D-Var methods that use an ensemble need to transform the ensemble perturbations using an ensemble Kalman filter. PDAF uses for this the error-subspace transform filter ESTKF. There are two variants: The first uses the localized filter LESTKF, while the second uses the global filter ESTKF.
    4040
    4141For the [wiki:Implement3DVarAnalysisOverviewPDAF3 analysis step of 3D-Var] we need different operations related to the observations. These operations are requested by PDAF by call-back routines supplied by the user and provided in the OMI structure. The names of the routines that are provided by the user are specified in the call to the routine `PDAF3_assimilate_3dvar_all` for the online mode of PDAF or `PDAF3_assim_offline_3dvar_all` for the offline mode.