Changes between Version 6 and Version 7 of OMI_observation_operators_PDAF3

Timestamp:

Sep 1, 2025, 11:25:44 AM (21 hours ago)

Author:

lnerger

Comment:

--

OMI_observation_operators_PDAF3

@@ -38 +38 @@
  - '''[wiki:PDAFomi_obs_op_gatheronly]'''[[br]]
   This observation operator is used for strongly coupled data assimililation in coupled models. It served for the particular case that model variables are observed in a coupled model system in another model component only. For this case, this observation operator only performs the gather operation to obtain the full observations.
-
-The arguments of the observation operators are
-{{{
-  SUBROUTINE PDAFomi_obs_op_X (thisobs,[nrows,] state_p, ostate)
+ - '''[wiki:PDAFomi_obs_op_extern]'''[[br]]
+  This observation operator is used for the case that the observed state is computed externally, e.g. directly in the model during a forecast. The interface of the observation operator allow the use to directly provide the observed state as an argument.
+
+
+The arguments of the observation operators, except `PDAFomi_obs_op_extern` are
+{{{
+  SUBROUTINE PDAFomi_obs_op_X(thisobs,[nrows,] state_p, ostate)
 
      TYPE(obs_f), INTENT(inout) :: thisobs  ! Data type with full observation
@@ -49 +52 @@
 }}}
 Where `thisobs` is the observation type variable, `state_p` is the input state vector provided by PDAF and `ostate` is the observed state that will be returned to PDAF. `nrows` only exists for the observation operators X=gridavg and X=interp_lin and specifies the number of grid points involved in the observation operation. For X=gridpoint, this argument does not exist.
+
+The arguments of the observation operator `PDAFomi_obs_op_extern` are
+{{{
+  SUBROUTINE PDAFomi_obs_op_extern(thisobs, ostate_p, ostate)
+
+     TYPE(obs_f), INTENT(inout) :: thisobs  ! Data type with full observation
+     REAL, INTENT(in)    :: ostate_p(:)     ! Process-local observed model state (provided by user)
+     REAL, INTENT(inout) :: obs_f_all(:)    ! Full observed state for all observation types (array provided by PDAF)
+}}}
+
 
 
@@ -151 +164 @@
   This observation operator is used for the case of linear interpolation. It uses the index array `thisobs%id_obs_p` and the array `thisobs%icoeff_p` holding interpolation coefficients initialized in `init_dim_obs_OBSTYPE`. To use this observation operator, one has to allocate and initialize `thisobs%icoeff_p` as described below. 
 
+Note: There is no adjoint observation operator for `PDAFomi_obs_op_extern` because the operation is user defined. Thus, the user one would need to implement the coresponding adjoint operator.
+
 The arguments of the observation operators are
 {{{