PDAF_assim_offline_ensrf

This page documents the routine PDAF_assim_offline_ensrf of PDAF. The routine is used to execute the ENSRF/EAKF filters, which were added to PDAF with version 3.0.

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

The interface for using the ENSRF/EAKF is the following:

SUBROUTINE PDAF_assim_offline_ensrf(U_init_dim_obs, U_obs_op,  U_init_obs, U_init_obsvars, &
     U_localize_covar_serial, &
     U_prepoststep, outflag)

with the following arguments:

• U_init_dim_obs:
  The name of the user-supplied routine that provides the size of observation vector
• U_obs_op:
  The name of the user-supplied routine that acts as the observation operator on some state vector
• U_init_obs:
  The name of the user-supplied routine that initializes the vector of observations
• U_init_obsvars:
  The name of the user-supplied routine that initializes the vector of observation error variances.
• U_localize_covar_serial:
  The name of the user-suppplied routine that applies the covariance localization for a single observation
• U_prepoststep:
  The name of the user-supplied pre/poststep routine as in PDAF_get_state
• status_pdaf:
  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 implementing the analysis step of the ENSRF/EAKF. Here also the possible choices of subtype are explained. These select the particular filter variant.

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.