Changes between Initial Version and Version 1 of U_init_obsvar


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Timestamp:
Jan 22, 2015, 9:39:21 AM (6 years ago)
Author:
lnerger
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  • U_init_obsvar

    v1 v1  
     1= `U_init_obsvar` =
     2
     3The page documents the user-supplied call-back routine `U_init_obsvar`.
     4
     5The routine `U_init_obsvar` 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_obsvar_pdaf`, but in the full interface, the user can choose the name of the routine.
     6The routine is used with the global filters ESTKF, ETKF, and SEIK as well as the local filters LESTKF, LETKF, and LSEIK. The routine is called during the filter analysis step. The routine is only called if the adaptive forgetting factor is used (`type_forget=1` in the example impementation). When the routine is called it has to return the mean observation error variance.
     7
     8The interface is the following:
     9{{{
     10SUBROUTINE U_init_obsvar(step, dim_obs_p, obs_p, meanvar)
     11}}}
     12with
     13 * `step` : `integer, intent(in)`[[BR]] Current time step
     14 * `dim_obs_p` : `integer, intent(in)`[[BR]] Size of observation vector
     15 * `obs_p` : `real, intent(in), dimension(dim_obs_p)`[[BR]] Vector of observations
     16 * `meanvar` : `real, intent(out)`[[BR]] Mean observation error variance
     17
     18Notes:
     19 * For a model with domain-decomposition one might use the mean variance for the model sub-domain of the calling process. Alternatively one can compute a mean variance for the full model domain using MPI communication (e.g. the function `MPI_allreduce`).
     20 * The observation vector `obs_p` is provided to the routine for the case that the observation error variance is relative to the value of the observations.