wiki:PDAF_assimilate_lseik

Version 1 (modified by lnerger, 6 years ago) (diff)

--

PDAF_assimilate_lseik

This page documents the routine PDAF_assimilate_lseik 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 when using the LSEIK filter is the following:

  SUBROUTINE PDAF_assimilate_lseik(U_collect_state, U_distribute_state, U_init_dim_obs_f, U_obs_op_f, &
                                  U_init_obs_f, U_init_obs_l, U_prepoststep, U_prodRinvA_l, &
                                  U_init_n_domains, U_init_dim_l, U_init_dim_obs_l, &
                                  U_g2l_state, U_l2g_state, U_g2l_obs, &
                                  U_init_obsvar, U_init_obsvar_l, U_next_observation, status_pdaf)

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 and also 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_f: The name of the user-supplied routine that provides the size of the full observation vector
  • U_obs_op_f: The name of the user-supplied routine that acts as the full observation operator on some state vector
  • U_init_obs_f: The name of the user-supplied routine that initializes the full vector of observations
  • U_init_obs_l: The name of the user-supplied routine that initializes the vector of observations for a local analysis domain
  • U_prepoststep: The name of the pre/poststep routine as in PDAF_get_state
  • U_prodRinvA_l: 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.
  • U_init_n_domains: The name of the routine that provides the number of local analysis domains
  • U_init_dim_l: The name of the routine that provides the state dimension for a local analysis domain
  • U_init_dim_obs_l: The name of the routine that initializes the size of the observation vector for a local analysis domain
  • U_g2l_state: The name of the routine that initializes a local state vector from the global state vector
  • U_l2g_state: The name of the routine that initializes the corresponding part of the global state vector from the the provided local state vector
  • U_g2l_obs: The name of the routine that initializes a local observation vector from a full observation vector
  • U_init_obsvar: The name of the user-supplied routine that provides a global mean observation error variance (This routine will only be executed, if an adaptive forgetting factor is used)
  • U_init_obsvar_l: The name of the user-supplied routine that provides a mean observation error variance for the local analysis domain (This routine will only be executed, if a local adaptive forgetting factor is used)
  • 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_pdaf: The integer status flag. It is zero, if PDAF_assimilate_lseik is exited without errors.

Note:

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

It is recommended that the value of status_pdaf is checked in the program after PDAF_assimilate_lseik is executed. Only if its value is 0 the initialization was successful.

PDAF also has a Simplified Interface providing the routine PDAF_assimilate_lseik_si. In the simplified interface, the name of the user-supplied routines have predefined names and do not appear in the call to PDAF_assimilate_lseik_si. More information on the pre-defined names is provided in the page on implementing the analysis step of the LSEIK filter.