Changes between Initial Version and Version 1 of PDAF_assimilate_enkf


Ignore:
Timestamp:
Jan 15, 2015, 3:28:04 PM (6 years ago)
Author:
lnerger
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • PDAF_assimilate_enkf

    v1 v1  
     1= PDAF_assimilate_enkf =
     2
     3This page documents the routine `PDAF_assimilate_enkf` of PDAF.
     4
     5The routine is typically called in `assimilate_pdaf` or directly in the model code.
     6
     7The general aspects of the filter specific routines `PDAF_assimilate_*` are described on the page [ModifyModelforEnsembleIntegration Modification of the model code for the ensemble integration] and its sub-page on [InsertAnalysisStep 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.
     8
     9The interface when using the EnKF is the following:
     10{{{
     11  SUBROUTINE PDAF_assimilate_enkf(U_collect_state, U_distribute_state, U_init_dim_obs, &
     12                                 U_obs_op, U_init_obs, U_prepoststep, U_add_obs_err, &
     13                                 U_init_obscovar, U_next_observation, status_pdaf)
     14}}}
     15with the following arguments:
     16 * `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.
     17 * `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.
     18 * `U_init_dim_obs`: The name of the user-supplied routine that provides the size of observation vector
     19 * `U_obs_op`: The name of the user-supplied routine that acts as the observation operator on some state vector
     20 * `U_init_obs`: The name of the user-supplied routine that initializes the vector of observations
     21 * `U_prepoststep`: The name of the pre/poststep routine as in `PDAF_get_state`
     22 * `U_add_obs_err`: The name of the user-supplied routine that adds the observation error covariance matrix to the ensemble covariance matrix projected onto the observation space.
     23 * `U_init_obscovar`: The name of the user-supplied routine that initializes the observation error covariance matrix.
     24 * `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`.
     25 * `status_pdaf`: The integer status flag. It is zero, if `PDAF_assimilate_enkf` is exited without errors.
     26
     27
     28The user-supplied call-back routines are described on the page on [ImplementAnalysisenkf implementing the analysis step of the EnKF].
     29
     30It is recommended that the value of `status_pdaf` is checked in the program after PDAF_assimilate_enkf is executed. Only if its value is 0 the initialization was successful.
     31
     32PDAF also has a [PdafSimplifiedInterface Simplified Interface] providing the routine `PDAF_assimilate_enkf_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_enkf_si`.  More information on the pre-defined names is provided in the [ImplementAnalysisenkf page on implementing the analysis step of the EnKF].
     33