| | 1 | = PDAF3_assimilate_enkf_nondiagR = |
| | 2 | |
| | 3 | This page documents the routine `PDAF3_assimilate_enkf_nondiagR` of PDAF. The routine is part of the advanced PDAF3 interface that was introduced with PDAF V3.0. |
| | 4 | |
| | 5 | The routine is used to execute the analysis step of the EnKF and LEnKF for the case of a non-diagonal observation error covariance matrix. |
| | 6 | |
| | 7 | The routine is typically called in `assimilate_pdaf` or directly in the model code. |
| | 8 | |
| | 9 | The general aspects of the filter specific routines `PDAF3_put_state_*` 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]. |
| | 10 | |
| | 11 | The routine is used for the offline mode of PDAF. It can also be used in the 'flexible' parallelization implementation variant of the data assimilation system, but starting with PDAF-3 we recommend to use [wiki:PDAF3_assimilate_local PDAF3_assimilate_local], which is also used with the 'fully-parallel' implementation variant. |
| | 12 | |
| | 13 | The interface is: |
| | 14 | {{{ |
| | 15 | SUBROUTINE PDAF3_assimilate_enkf_nondiagR(U_collect_state, U_distribute_state, & |
| | 16 | U_init_dim_obs_pdafomi, U_obs_op_pdafomi, & |
| | 17 | U_add_obs_err_pdafomi, U_init_obscovar_pdafomi, & |
| | 18 | U_prepoststep, U_next_observation, status) |
| | 19 | }}} |
| | 20 | with the following arguments: |
| | 21 | * `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 `PDAF_get_state` as well as here. |
| | 22 | * `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. This is the inverse operation to `U_collect_state`. |
| | 23 | * `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. |
| | 24 | * `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. |
| | 25 | * `U_add_obs_err_pdafomi`: [[BR]]The name of the user-supplied routine that adds the observation error covariance matrix to the ensemble covariance matrix projected onto the observation space. |
| | 26 | * `U_init_obscovar_pdafomi`: [[BR]]The name of the user-supplied routine that initializes the observation error covariance matrix. |
| | 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 a 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. |
| | 30 | |
| | 31 | Notes: |
| | 32 | * The difference to the routine `PDAF3_assimilate_global` used for diagonal R-matrices is only in the additional arguments `U_add_obs_err_pdafomi` and `U_init_obscovar_pdafomi`. |
| | 33 | * The global filters ESTKF, ETKF, and SEIK use the separate routine [wiki:PDAF3_assimilate_global_nondiagR]. |
| | 34 | * The global filters NETF and PF use the separate routine [wiki:PDAF3_assimilate_nonlin_nondiagR]. |
| | 35 | * It is recommended that the value of `status_pdaf` is checked in the program after this routine is executed. Only if its value is 0 the initialization was successful. |
| | 36 | |
| | 37 | The user-supplied call-back routines are described on the page on [ImplementAnalysisGlobal implementing the analysis step of the global filters]. |
