PDAF3_assim_offline_nonlin_nondiagR

This page documents the routine PDAF3_assim_offline_nonlin_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 nonlinear filters NETF and PF for the case 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_nonlin_nondiagR(U_init_dim_obs_pdafomi, U_obs_op_pdafomi, U_likelihood_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_prodRinvA_pdafomi: 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. This routine is part of an OMI observation module.
• U_likelihood_pdafomi:
  The name of the user-supplied routine that compute the likelihood of an ensemble state.
• 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 diagonal R-matrices is only in the additonal argument U_likelihood_pdafomi.
• The global filters ESTKF, ETKF, and SEIK use the separate routine PDAF3_assim_offline_global_nondiagR.
• The filter EnKF uses the separate routine PDAF3_assim_offline_enkf_nondiagR.
• 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.

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