PDAF_iau_set_weights

This page documents the routine PDAF_iau_set_weights of PDAF, which was introduced with PDAF V3.0.

This routine allows the user to provide a user-specified vector of increment weights. While PDAF_iau_init allows to choose among pre-defined weight functions, one might like to use a different function and the corresponding weight can be set here.

The routine has to be called by all processes that are model processes. A common place is to call the routine in assimilate_pdaf after an analysis step or in distribute_state_pdaf.

The interface is the following:

  SUBROUTINE PDAF_iau_set_weights(iweights, weights)

    INTEGER, INTENT(in) :: iweights        ! Length of weights input vector
    REAL, INTENT(in) :: weights(iweights)  ! Input weight vector

Hints:

• If iweights is different from the number of IAU steps set in PDAF_iau_init or PDAF_iau_reset only the minimum of iweights and the set IAU steps is filled with the provided weights vector.
• We recommend to only change the weights vector before a forecast phase.
• While setting different weight functions for different processes or model tasks is possible this likely leads to inconsistencies.