PDAF3_put_state_lenkf

This page documents the routine PDAF3_put_state_lenkf of PDAF. The routine is part of the advanced PDAF3 interface that was introduced with PDAF V3.0.

Note: This routine exists for backward-compatibility for the LEnKF with PDAF V2.3, in particular for existing implementations using localize_covar_pdafomi. We recommend to use the new PDAF3 interface using PDAF3_put_state_global that avoids the need to implement the additional call-back routine localize_covar_pdafomi.

The routine is typically called in assimilate_pdaf or directly in the model code.

The general aspects of the filter specific routines PDAF3_put_state_* are described on the page Modification of the model code for the ensemble integration and its sub-page on inserting the analysis step.

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 PDAF3_assimimilate_global for the 'flexible' parallelization variant, which is also used with the 'fully-parallel' implementation variant.

Here, we list the full interface of the routine.

The interface is:

  SUBROUTINE PDAF3_put_state_lenkf(U_collect_state, &
                                 U_init_dim_obs_pdafomi, U_obs_op_pdafomi, &
                                 U_prepoststep, U_localize_covar_pdafomi, &
                                 status)

with the following arguments:

• U_collect_state: 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.
• U_init_dim_obs_pdafomi: The name of the user-supplied routine that initializes the observation information and provides the size of observation vector
• U_obs_op_pdafomi: The name of the user-supplied routine that acts as the observation operator on some state vector
• U_localize_covar_pdafomi: The name of the user-supplied routine that Applies covariance localization to the matrices HP and HPH^T
• U_prepoststep: The name of the user-supplied pre/poststep routine as in PDAF_get_state (Note that the place of U_prepoststep has changed compared to the previous routine PDAFomi_assimilate_lenkf)
• status: The integer status flag. It is zero, if the routine is exited without errors.

For the EnKF, the user-supplied routines are essentially executed in the order they are listed in the interface to PDAFomi_put_state_lenkf.

The user-supplied call-back routines are described on the page on implementing the analysis step of the local EnKF.

It is recommended that the value of status_pdaf is checked in the program after PDAFomi_put_state_lenkf is executed. Only if its value is 0 the initialization was successful.