Changes between Version 11 and Version 12 of ImplementAnalysis_3DVar_classical


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Timestamp:
Jun 4, 2025, 11:57:01 AM (2 days ago)
Author:
lnerger
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  • ImplementAnalysis_3DVar_classical

    v11 v12  
    4444== Overview ==
    4545
    46 With Version 2.0 with introduced 3D variational assimilation methods to PDAF. There are genenerally three different variants: parameterized 3D-Var, 3D Ensemble Var, and hybrid (parameterized + ensemble) 3D-Var.
    47 
    48 This page describes the implementation of the analysis step for the parameterized 3D-Var in the classical way (without using PDAF-OMI).
     46PDAF provides genenerally three different variants: parameterized 3D-Var, 3D Ensemble Var, and hybrid (parameterized + ensemble) 3D-Var. These methods were introduced with PDAF V2.0.
     47
     48This page describes the implementation of the analysis step for the parameterized 3D-Var using PDAF's full interface (thus, without using PDAF-OMI).
    4949
    5050For the analysis step of 3D-Var we need different operations related to the observations. These operations are requested by PDAF by calling user-supplied routines. Intentionally, the operations are split into separate routines in order to keep the operations rather elementary as this procedure should simplify the implementation. The names of the required routines are specified in the call to the routine `PDAF_assimilate_3dvar` in the fully-parallel implementation (or `PDAF_put_state_3dvar` for the 'flexible' implementation) described below. With regard to the parallelization, all these routines (except `U_collect_state`) are executed by the filter processes (`filterpe=.true.`) only.
    … …  
    5555== `PDAF_assimilate_3dvar` ==
    5656
    57 The general aspects of the filter (or solver) specific routines `PDAF_assimilate_*` have been described on the page [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3 Modification of the model code for the ensemble integration]. The routine is used in the fully-parallel implementation variant of the data assimilation system. When the 'flexible' implementation variant is used, the routines `PDAF_put_state_*` is used as described further below. Here, we list the full interface of the routine. Subsequently, the user-supplied routines specified in the call is explained.
    58 
    59 The interface for using the parameterized 3D-Var is:
     57This routine is used both in the ''fully-parallel'' and the ''flexible'' implementation variants of the data assimilation system. (See the page [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3 Modification of the model code for the ensemble integration] for these variants)
     58
     59Here, we list the full interface of the routine. Subsequently, the user-supplied routines specified in the call are explained.
     60
     61The interface is:
    6062{{{
    6163  SUBROUTINE PDAF_assimilate_3dvar(U_collect_state, U_distribute_state, &
    … …  
    8082
    8183
     84
     85== `PDAF_assim_offline_3dvar ` ==
     86
     87This routine is used to perform the analysis step for the offline mode of PDAF.
     88The interface of the routine is identical with that of the 'assimilate'-routine, except that the user-supplied routines `U_distribute_state`, `U_collect_state` and `U_next_observation` are missing.
     89
     90The 'assim_offline' routines were introduced with PDAF V3.0 to simplify the [wiki:OfflineImplementationGuide_PDAF3 implementation of the offline mode].
     91
     92The interface is:
     93{{{
     94  SUBROUTINE PDAF_assim_offline_3dvar( &
     95                                 U_init_dim_obs, U_obs_op, U_init_obs, U_prodRinvA, &
     96                                 U_cvt, U_cvt_adj, U_obs_op_lin, U_obs_op_adj, &
     97                                 U_prepoststep, outflag)
     98}}}
     99
    82100== `PDAF_put_state_3dvar` ==
    83101
    84 When the 'flexible' implementation variant is chosen for the assimilation system, the routine `PDAF_put_state_3dvar` has to be used instead of `PDAF_assimilate_3dvar`. The general aspects of the filter specific routines `PDAF_put_state_*` have been described on the page [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3 Modification of the model code for the ensemble integration]. The interface of the routine is identical with that of `PDAF_assimilate_global` with the exception the specification of the user-supplied routines `U_distribute_state` and `U_next_observation` are missing.
    85 
    86 The interface for using the parameterized 3D-Var is:
     102This routine exists for backward-compatibility. In implementations that were done for PDAF V2.3.1 and before, a 'put_state' routine was used for the [wiki:OnlineFlexible_PDAF3 'flexible' parallelization variant] and for the [wiki:OfflineImplementationGuide_PDAF3 offline mode].  This routine allows to continue using the previous implementation structure.
     103The interface of the routine is identical with that of the 'assimilate'-routine, except that the user-supplied routines `U_distribute_state` and `U_next_observation` are missing.
     104
     105The interface is:
    87106{{{
    88107  SUBROUTINE PDAF_put_state_3dvar(collect_state_pdaf, &
    … …  
    94113== User-supplied routines ==
    95114
    96 Here all user-supplied routines are described that are required in the call to `PDAF_assimilate_3dvar`. For some of the generic routines, we link to the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3 modifying the model code for the ensemble integration].
     115Here all user-supplied routines are described that are required in the call to the analysis routine. For some of the generic routines, we link to the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3 modifying the model code for the ensemble integration].
    97116
    98117To indicate user-supplied routines we use the prefix `U_`. In the tutorials in `tutorial/` and in the template directory `templates/` these routines exist without the prefix, but with the extension `_pdaf`. The files are named correspondingly. In the section titles below we provide the name of the template file in parentheses.
    … …  
    101120
    102121
    103 
    104 
    105122=== `U_collect_state` (collect_state_pdaf.F90) ===
    106123
    107 This routine is independent of the filter algorithm used.
    108 
    109 See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#U_collect_statecollect_state_pdaf.F90 inserting the analysis step] for the description of this routine.
     124This routine is independent of the DA method used.
     125
     126See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#collect_state_pdafcollect_state_pdaf.F90 modifying the model code for the ensemble integration] for the description of this routine.
    110127
    111128
    112129=== `U_distribute_state` (distribute_state_pdaf.F90) ===
    113130
    114 This routine is independent of the filter algorithm used.
    115 
    116 See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#U_distribute_statedistribute_state_pdaf.F90 inserting the analysis step] for the description of this routine.
     131This routine is independent of the DA method used.
     132
     133See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#distribute_state_pdafdistribute_state_pdaf.F90 modifying the model code for the ensemble integration] for the description of this routine.
    117134
    118135
    … …  
    302319=== `U_next_observation` (next_observation_pdaf.F90) ===
    303320
    304 This routine is independent of the filter algorithm used.
    305 
    306 See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#U_next_observationnext_observation_pdaf.F90 inserting the analysis step] for the description of this routine.
     321This routine is independent of the DA method used.
     322
     323See the page on [wiki:OnlineModifyModelforEnsembleIntegration_PDAF3#next_observation_pdafnext_observation_pdaf.F90 modifying the model code for the ensemble integration] for the description of this routine.
    307324
    308325