Changes between Version 1 and Version 2 of ImplementAnalysis_3DVar_classical


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Timestamp:
Dec 9, 2021, 12:15:17 PM (12 months ago)
Author:
lnerger
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  • ImplementAnalysis_3DVar_classical

    v1 v2  
    4141With 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.
    4242
    43 This page describes the implementation of the analysis step for the parameterized 3D-Var in the classical way without using PDAF-OMI.
     43This page describes the implementation of the analysis step for the parameterized 3D-Var in the classical way (without using PDAF-OMI).
    4444
    4545For 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.
     
    7575
    7676
    77 == `PDAFomi_put_state_global` ==
    78 
    79 When the 'flexible' implementation variant is chosen for the assimilation system, the routine `PDAFomi_put_state_global` has to be used instead of `PDAFomi_assimilate_global`. The general aspects of the filter specific routines `PDAF_put_state_*` have been described on the page [ModifyModelforEnsembleIntegration 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.
     77== `PDAF_put_state_3dvar` ==
     78
     79When 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 [ModifyModelforEnsembleIntegration 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.
    8080
    8181The interface when using one of the global filters is the following:
    8282{{{
    83   SUBROUTINE PDAFomi_assimilate_3dvar(collect_state_pdaf, &
     83  SUBROUTINE PDAF_put_state_3dvar(collect_state_pdaf, &
    8484                                 U_init_dim_obs, U_obs_op, U_init_obs, U_prodRinvA, &
    8585                                 U_cvt, U_cvt_adj, U_obs_op_lin, U_obs_op_adj, &
     
    8989== User-supplied routines ==
    9090
    91 Here all user-supplied routines are described that are required in the call to `PDAFomi_assimilate_3dvar`. For some of the generic routines, we link to the page on [ModifyModelforEnsembleIntegration modifying the model code for the ensemble integration].
    92 
    93 To indicate user-supplied routines we use the prefix `U_`. In the template directory `templates/` as well as in the tutorial implementations in `tutorial/` these routines exist without the prefix, but with the extension `_pdaf.F90`. The user-routines relating to OMI are collected in the file `callback_obs_pdafomi.F90`. In the section titles below we provide the name of the template file in parentheses.
     91Here 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 [ModifyModelforEnsembleIntegration modifying the model code for the ensemble integration].
     92
     93To indicate user-supplied routines we use the prefix `U_`. In the template directory `templates/` as well as in the example implementation in `testsuite/src/dummymodel_1D` these routines exist without the prefix, but with the extension `_pdaf.F90`. In the section titles below we provide the name of the template file in parentheses.
    9494
    9595In the subroutine interfaces some variables appear with the suffix `_p`. This suffix indicates that the variable is particular to a model sub-domain, if a domain decomposed model is used. Thus, the value(s) in the variable will be different for different model sub-domains.
     96
     97
    9698
    9799
     
    239241
    240242
    241 === `U_obs_op_lin` (obs_op_pdaf_lin.F90) ===
     243=== `U_obs_op_lin` (obs_op_lin_pdaf.F90) ===
    242244
    243245This routine is used by all 3D-Var methods.
     
    262264
    263265
    264 === `U_obs_op_adj` (obs_op_pdaf_adj.F90) ===
     266=== `U_obs_op_adj` (obs_op_adj_pdaf.F90) ===
    265267
    266268This routine is used by all 3D-Var methods.
     
    302304== Execution order of user-supplied routines ==
    303305
    304 The user-supplied routines are essentially executed in the order they are listed in the interface to `PDAFomi_assimilate_3dvar`. The order can be important as some routines can perform preparatory work for later routines. For example, `U_init_dim_obs_pdafomi` prepares an index array that provides the information for executing the observation operator in `U_obs_op_pdafomi`. How this information is initialized is described in the documentation of OMI.
     306The user-supplied routines are essentially executed in the order they are listed in the interface to `PDAF_assimilate_3dvar`. The order can be important as some routines can perform preparatory work for later routines. For example, `U_init_dim_obs` prepares an index array that provides the information for executing the observation operator in `U_obs_op`.
    305307
    306308Before the analysis step is called the following routine is executed:
     
    309311The analysis step is executed when the ensemble integration of the forecast is completed. During the analysis step the following routines are executed in the given order:
    310312 1. [#U_prepoststepprepoststep_ens_pdaf.F90 U_prepoststep] (Call to act on the forecast ensemble, called with negative value of the time step)
    311  1. [#U_init_dim_obs_pdafomicallback_obs_pdafomi.F90 U_init_dim_obs_pdafomi]
    312  1. [#U_obs_op_pdafomicallback_obs_pdafomi.F90 U_obs_op_pdafomi] (multiple calls, one for each ensemble member)
     313 1. [#U_init_dim_obsinit_dim_obs_pdaf.F90 U_init_dim_obs]
     314 1. [#U_obs_opobs_op_pdaf.F90 U_obs_op]
     315 1. [#U_init_obsinit_obs_pdaf.F90 U_init_obs]
    313316
    314317Inside the analysis step the interative optimization is computed. This involves the repeated call of the routines:
    315318 1. [#U_cvtcvt_pdaf.F90 U_cvt]
    316  1. [#U_obs_op_linpdafomicallback_obs_pdafomi.F90 U_obs_op_lin_pdafomi]
    317  1. [#U_obs_op_adjpdafomicallback_obs_pdafomi.F90 U_obs_op_adj_pdafomi]
     319 1. [#U_obs_op_linobs_op_lin_pdaf.F90 U_obs_op_lin]
     320 1. [#U_prodRinvAprodrinva_pdaf.F90 U_prodRinvA]
     321 1. [#U_obs_op_adjobs_op_adj_pdaf.F90 U_obs_op_adj]
    318322 1. [#U_cvt_adjcvt_adj_pdaf.F90 U_cvt_adj]
    319323
     
    322326 1. [#U_prepoststepprepoststep_ens_pdaf.F90 U_prepoststep] (Call to act on the analysis ensemble, called with (positive) value of the time step)
    323327
    324 In case of the routine `PDAFomi_assimilate_3dvar`, the following routines are executed after the analysis step:
     328In case of the routine `PDAF_assimilate_3dvar`, the following routines are executed after the analysis step:
    325329 1. [#U_distribute_statedistribute_state_pdaf.F90 U_distribute_state]
    326330 1. [#U_next_observationnext_observation_pdaf.F90 U_next_observation]