PDAFomi_obs_op_gatheronly

This page documents the routine PDAFomi_obs_op_gatheronly of PDAF-OMI.

This routine provides the application of observation operator for the case that model variables are observed in a coupled model system only in another model component. Thus, dim_obs_p=0 for the calling model component. Accordingly, this observation operator only performs the gather operation to obtain the full observations. An example for using this observation operator is in the case of a coupled atmosphere-ocean model in which the atmosphere component model runs with different processes than the ocean components. If one assimilates observations of the ocean with strongly-coupled data assimilation into the atmosphere in this system, the atmosphere would call PDAFomi_obs_op_gatheronly, while the ocean would call, e.g., an observation operator involving interpolation.

The routine is usually called in obs_op_OBSTYPE in an OMI observation module.

See the page describing PDAF-OMI observation operators for a general overview.

The interface is:

  SUBROUTINE PDAFomi_obs_op_gatheronly(thisobs, state_p, obs_f_all)

    TYPE(obs_f), INTENT(inout) :: thisobs  ! Data type with full observation
    REAL, INTENT(in)    :: state_p(:)      ! Process-local model state provided by PDAF
    REAL, INTENT(inout) :: obs_f_all(:)    ! Full observed state for all observation types (array provided by PDAF)

Note:

• This observation operator requires that the filter processes for all coupled model components are in the same MPI communicator, so that a joint multi-component state vector exists.