PDAF_assim_flag

This page documents the function PDAF_assim_flag of PDAF. This routine was added with PDAF V3.1 as an alternative to the routine PDAF_get_assim_flag.

The function returns the information whether in the last call to a routine PDAF_assimilate_X (with X being any of the filterts) observations were assimilated, i.e. an analysis step was computed. It can be called during the ensemble integration, if a program needs this information, e.g. if a model uses leafrog time stepping and one wishes to do an Euler time step directly after the analysis step.

The function is typically called in the model code during the ensemble integration. It only works in the online mode of PDAF.

The interface is the following:

  INTEGER FUNCTION PDAF_assim_flag()

the function returns the value:

• assim_flag : (1) if an analysis step was computed, (0) otherwise.

Note: The return value can be directly used, e.g. as

  IF (PDAF_assim_flag() == 1) THEN
    Special operation depending on that DA was done
  ENDIF

An example, where this is used is to enable performing an Euler time step in a model that otherwise performs leap frog time stepping.