= PDAF_generate_obs_si = 

This page documents the routine `PDAF_generate_obs_si` of PDAF. 

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

This routine is used to generate synthetic observations. It is the simple-interface variante of [PDAF_generate_obs], having only a single argument and using predefined names for the call-back routines.
The routine bases on the usual implementation strategy for PDAF which is 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 routine `PDAF_put_state_generate_obs' is used. 

The interface is the following:
{{{
  SUBROUTINE PDAF_generate_obs_si(status_pdaf)
}}}
with the following arguments:
 * `status_pdaf`: The integer status flag. It is zero, if `PDAF_generate_obs_si` is exited without errors.

The routine calls several user-supplied call-back routines. They are described on the page on [ImplementGenenerateObs implementing the generation of synthetic observations].

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