Changes between Initial Version and Version 1 of add_obs_error_pdaf

Timestamp:

Jan 21, 2016, 11:40:43 AM (9 years ago)

Author:

lnerger

Comment:

--

add_obs_error_pdaf

@@ +1 @@
+= `add_obs_error_pdaf`=
+
+The page document the user-supplied call-back routine `add_obs_error_pdaf`.
+
+The routine `add_obs_error_pdaf` (called `U_add_obs_err` inside the PDAF core routines) is a call-back routine that has to be provided by the user. 
+The routine is used by the EnKF and called during the filter analysis step. The purpose of the routine is to add the observation error covariance matrix to the input/output matrix `C`. This matrix is the projection of the ensemble covariance matrix onto the observation space that is computed during the analysis step of the EnKF.
+
+The interface is the following:
+{{{
+SUBROUTINE add_obs_error_pdaf(step, dim_obs, C)
+}}}
+with 
+ * `step` : `integer, intent(in)`[[BR]] Current time step
+ * `dim_obs` : `integer, intent(in)`[[BR]] Size of observation vector
+ * `C` : `real, intent(inout), dimension(dim_obs,dim_obs)`[[BR]] Matrix to which the observation error covariance matrix is added
+
+The routine is called during the analysis step. 
+
+The operation is for the global observation space. Thus, it is independent of whether the filter is executed with or without parallelization.
+
+Hints:
+ * The routine does not require that the observation error covariance matrix is added as a full matrix. If the matrix is diagonal, only the diagonal elements have to be added.