PDAF3_assim_offline_lenkf

This page documents the routine PDAF3_assim_offline_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 used for the offline coupled mode of PDAF, which is described on the page: Implementation Guide for Offline Coupling.

The interface is:

  SUBROUTINE PDAF3_assim_offline_lenkf(U_init_dim_obs_pdafomi, U_obs_op_pdafomi, &
                                 U_localize_covar_pdafomi, U_prepoststep, &
                                 status)

with the following arguments:

• 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.