wiki:PDAFomi_assimilate_en3dvar_estkf

Version 1 (modified by lnerger, 12 months ago) (diff)

--

PDAFomi_assimilate_en3dvar_estkf

This page documents the routine PDAFomi_assimilate_en3dvar_estkf of PDAF.

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

The general aspects of the filter specific routines PDAF_assimilate_* 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 in the fully-parallel implementation variant of the data assimilation system. When the 'flexible' implementation variant, the routines `PDAF_put_state_*' are used.

The interface is:

SUBROUTINE PDAFomi_assimilate_en3dvar_estkf(U_collect_state, U_distribute_state, &
                                 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_prepoststep, U_next_observation, outflag)

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_distribute_state: The name of a user supplied routine that initializes the model fields from the array holding the ensemble of model state vectors.
  • 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_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_lin_pdafomi: The name of the user-supplied routine that acts as the linearized observation operator on some state vector
  • U_obs_op_lin_pdafomi: The name of the user-supplied routine that acts as the adjoint observation operator on some state vector
  • U_prepoststep: The name of the pre/poststep routine as in PDAF_get_state
  • U_next_observation: The name of a user supplied routine that initializes the variables nsteps, timenow, and doexit. The same routine is also used in PDAF_get_state.
  • status: The integer status flag. It is zero, if the routine is exited without errors.

The user-supplied call-back routines are described on the page on [ImplementAnalysis_3DEnVar implementing the analysis step of 3D Ensemble Var with OMI].

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.