PDAF3_assim_offline_en3dvar

This page documents the routine PDAF3_assim_offline_en3dvar. The routine is part of the advanced PDAF3 interface that was introduced with PDAF V3.0.

This routine is use to run the ensemble 3D-Var with either LESTKF or the global ESTKF for updating the ensemble perturbations.

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_en3dvar(U_init_dim_obs_pdafomi, U_obs_op_pdafomi, &
                                 U_cvt_ens, U_cvt_adj_ens, U_obs_op_lin_pdafomi, U_obs_op_adj_pdafomi, &
                                 U_init_n_domains_p, U_init_dim_l, U_init_dim_obs_l_pdafomi, &
                                 U_prepoststep, outflag)

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_cvt_ens:
  The name of the user-supplied routine that applies the ensemble control-vector transformation (square-root of the B-matrix) on some control vector to obtain a state vector.
• U_cvt_adj_ens:
  The name of the user-supplied routine that applies the adjoint ensemble control-vector transformation (with square-root of the B-matrix) on some state vector to obtain the control vector.
• 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_obs_op_lin_pdafomi:
  The name of the user-supplied routine that acts as the linearized observation operator on some state vector. This routine is part of an OMI observation module.
• `U_obs_op_adj_pdafomi:
  The name of the user-supplied routine that acts as the adjoint observation operator on some state vector. This routine is part of an OMI observation module.
• U_init_n_domains:
  The name of the user-supplied routine that provides the number of local analysis domains
• U_init_dim_l:
  The name of the user-supplied routine that provides the state dimension for a local analysis domain
• U_init_dim_obs_l_pdafomi:
  The name of the user-supplied routine that initializes the size of the observation vector for a local analysis domain
• 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. 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 [ImplementAnalysis_3DEnVar implementing the analysis step of 3D Ensemble Var with OMI].