Changes between Initial Version and Version 1 of U_init_obs_covar


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Timestamp:
Jan 21, 2016, 1:30:55 PM (5 years ago)
Author:
lnerger
Comment:

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  • U_init_obs_covar

    v1 v1  
     1= U_init_obs_covar =
     2
     3The page documents the user-supplied call-back routine `U_init_obs_covar`.
     4
     5The routine `U_init_obs_covar` is a call-back routine that has to be provided by the user.  In the simplified interface the predefined name of the routine is `init_obscovar_pdaf`, but in the full interface, the user can choose the name of the routine.
     6The routine is used only with the EnKF. The routine is called during the analysis step and is required for the generation of an ensemble of observations. It has to initialize the global observation error covariance matrix. In addition, a flag has to be initialized to provide the information, whether the observation error covariance matrix is diagonal.
     7
     8
     9The interface is the following:
     10{{{
     11SUBROUTINE U_init_obs_covar(step, dim_obs, dim_obs_p, covar, obs_p, isdiag)
     12}}}
     13with
     14 * `step` : `integer, intent(in)`[[BR]] Current time step
     15 * `dim_obs` : `integer, intent(in)`[[BR]] Global size of observation vector
     16 * `dim_obs_p` : `integer, intent(in)`[[BR]] Size of process-local observation vector
     17 * `covar` : `real, intent(out)`[[BR]] Observation error covariance matrix
     18 * `obs_p` : `real, intent(in), dimension(dim_obs_p)`[[BR]] Process-local vector of observations
     19 * `isdiag` : `logical, intent(out)`[[BR]]  Flag whether the observation error covar. matrix is diagonal
     20
     21
     22The initialization of `covar` is for the global observation space. Thus, it is independent of whether the filter is executed with or without parallelization.
     23
     24Hints:
     25 * The local observation vector `obs_p` is provided to the routine for the case that the observation errors are relative to the value of the observation.