PDAF_get_localfilter

This page documents the routine PDAF_get_localfilter of PDAF.

The routine returns the information whether the chosen filter is a domain-localized filter (LESTKF, LETKF, LSEIK, LNETF). It can be called in assimilate_pdaf.F90 and the return value can be used to call either PDAFomi_assimilate_global or PDAFomi_assimilate_local (or PDAFomi_put_state_global or PDAFomi_put_state_local). The value is initialized after calling PDAF_init.

The routine is typically called in the model code in assimilate_pdaf.

The interface is the following:

  SUBROUTINE PDAF_get_localfilter(lflag)

with the following argument:

• lflag: On output the integer index is
  (1) for local filters,
  (0) for global filters (including LEnKF, which performs covariance localization)

Notes:

• The difference between the return values 0 and 1 is mainly the way how PDAF-OMI handles observations.
• New for PDAF3: For the ENSRF/EAKF, lflag is also 1. This is because the observation handling for the ENSRF/EAKF uses the same approach as for domain-localized filters
• The value of lflag can be used, e.g. as

    IF (lflag == 1) THEN
      CALL PDAFomi_assimilate_local(...)
    ELSE
      CALL PDAFomi_assimilate_global(...)
    ENDIF