| | 1 | = PDAF3_assimilate_3dvar_nondiagR = |
| | 2 | |
| | 3 | This page documents the routine `PDAF3_assimilate_3dvar_nondiagR` which is used for the case of a non-diagonal observation error covariance matrix. The routine is part of the advanced PDAF3 interface that was introduced with PDAF V3.0. |
| | 4 | |
| | 5 | The routine is typically called in `assimilate_pdaf` or directly in the model code. |
| | 6 | |
| | 7 | The general aspects of the filter specific routines `PDAF3_assimilate_*` are described on the page [ModifyModelforEnsembleIntegration Modification of the model code for the ensemble integration] and its sub-page on [InsertAnalysisStep inserting the analysis step]. The routine is used in both the fully-parallel and the flexible parallelization variant of the data assimilation system. |
| | 8 | |
| | 9 | The interface for using the parameterized 3D-Var is: |
| | 10 | {{{ |
| | 11 | SUBROUTINE PDAF3_assimilate_3dvar_nondiagR(U_collect_state, U_distribute_state, & |
| | 12 | U_init_dim_obs_pdafomi, U_obs_op_pdafomi, U_prodRinvA_pdafomi, & |
| | 13 | U_cvt, U_cvt_adj, U_obs_op_lin_pdafomi, obs_op_adj_pdafomi, & |
| | 14 | U_prepoststep, U_next_observation, outflag) |
| | 15 | }}} |
| | 16 | with the following arguments: |
| | 17 | * `U_collect_state`: [[BR]]The name of the user-supplied routine that initializes a state vector from the array holding the ensemble of model states from the model fields. This is basically the inverse operation to `U_distribute_state` used in [ModifyModelforEnsembleIntegration#PDAF_get_state PDAF_get_state] and also here. |
| | 18 | * `U_distribute_state`: [[BR]]The name of a user supplied routine that initializes the model fields from the array holding the ensemble of model state vectors. |
| | 19 | * `U_init_dim_obs_pdafomi`: [[BR]]The name of the user-supplied routine that initializes the observation information and provides the size of observation vector. This routine is part of an OMI observation module. |
| | 20 | * `U_obs_op_pdafomi`: [[BR]]The name of the user-supplied routine that acts as the observation operator on some state vector. This routine is part of an OMI observation module. |
| | 21 | * `U_prodRinvA_pdafomi`: [[BR]]The name of the user-supplied routine that computes the product of the inverse of the observation error covariance matrix with some matrix provided to the routine by PDAF. |
| | 22 | * `U_cvt`: The name of the user-supplied routine that applies the control-vector transformation (square-root of the B-matrix) on some control vector to obtain a state vector. |
| | 23 | * `U_cvt_adj`: The name of the user-supplied routine that applies the adjoint control-vector transformation (with square-root of the B-matrix) on some state vector to obtain the control vector. |
| | 24 | * `U_obs_op_pdafomi`: The name of the user-supplied routine that acts as the observation operator on some state vector. This routine is part of an OMI observation module. |
| | 25 | * `U_obs_op_lin_pdafomi`: The name of the user-supplied routine that acts as the linearized observation operator on some state vector. This routine is part of an OMI observation module. |
| | 26 | * `U_obs_op_adj_pdafomi]: The name of the user-supplied routine that acts as the adjoint observation operator on some state vector. This routine is part of an OMI observation module. |
| | 27 | * `U_prepoststep`: [[BR]]The name of the user-supplied pre/poststep routine as in `PDAF_get_state` |
| | 28 | * `U_next_observation`: [[BR]]The name of the user-supplied routine that initializes the variables `nsteps`, `timenow`, and `doexit`. The same routine is also used in `PDAF_get_state`. |
| | 29 | * `status`: [[BR]]The integer status flag. It is zero, if the routine is exited without errors. It is recommended that the value of `status_pdaf` is checked in the program after the routine is executed. Only if its value is 0 the initialization was successful. |
| | 30 | |
| | 31 | **Note:** |
| | 32 | * The difference to the routine `PDAF3_assimilate_3dvar` used for diagonal R-matrices is only in the additonal argument `U_prodRinvA_pdafomi`. |
| | 33 | |
| | 34 | The user-supplied call-back routines are described on the page on [wiki:ImplementAnalysis_3DVar implementing the analysis step of 3D-Var with OMI]. |
| | 35 | |
| | 36 | |
| | 37 | |
