PDAF3_assim_offline_enkf_nondiagR

This page documents the routine PDAF3_assim_offline_enkf_nondiagR of PDAF. The routine is part of the advanced PDAF3 interface that was introduced with PDAF V3.0.

The routine is used to execute the analysis step of the EnKF and LEnKF of a non-diagonal observation error covariance matrix.

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_enkf_nondiagR(U_init_dim_obs_pdafomi, U_obs_op_pdafomi, &
                                 U_add_obs_err_pdafomi, U_init_obscovar_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. This routine is part of an OMI observation module.
• 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.
• U_add_obs_err_pdafomi:
  The name of the user-supplied routine that adds the observation error covariance matrix to the ensemble covariance matrix projected onto the observation space.
• U_init_obscovar_pdafomi:
  The name of the user-supplied routine that initializes the observation error covariance matrix.
• U_prepoststep:
  The name of the user-supplied pre/poststep routine as in PDAF_get_state
• status:
  The integer status flag. It is zero, if the routine is exited without errors.

Notes:

• The difference to the routine PDAF3_assim_offline_global used for diagdonal R-matrices is only in the additonal arguments U_add_obs_err_pdafomi and U_init_obscovar_pdafomi.
• The global filters ESTKF, ETKF, and SEIK use the separate routine PDAF3_assim_offline_global_nondiagR.
• The global filters NETF and PF use the separate routine PDAF3_assim_offline_nonlin_nondiagR.
• 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.

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