Changes between Version 1 and Version 2 of next_observation_pdaf


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Timestamp:
Jan 19, 2015, 9:56:59 PM (6 years ago)
Author:
lnerger
Comment:

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  • next_observation_pdaf

    v1 v2  
    1 = U_next_observation =
     1= next_observation_pdaf =
    22
    3 The page document the user-supplied call-back routine `U_next_observation`.
     3The page document the user-supplied call-back routine `next_observation_pdaf`.
    44
    5 The routine `U_next_observation` is a call-back routine that has to be provided by the user. In the simplified interface the predefined name of the routine is `next_observation_pdaf`, but in the full interface, the user can choose the name of the routine. At the beginning of a forecast phase, `U_next_observation` is called once by either `PDAF_get_state` ot `PDAF_assimilate_X` (with X being the name of a filter algorithm) to get the number of time steps to be computed in the forecast phase.
     5
     6The routine `init_ens_pdaf` (called `U_init_ens` in the PDAF core routines) is a call-back routine that has to be provided by the user. `init_ens_pdaf` is called by `PDAF_init` at the initialization stage of a data assimilation program. The purpose of the routine is to fill the ensemble array that is provided by PDAF with an initial ensemble of model states.
     7
     8
     9The routine `next_observation_pdaf` (called `U_next_observation` in the PDAF core routines) is a call-back routine that has to be provided by the user. At the beginning of a forecast phase, `next_observation_pdaf` is called once by either `PDAF_get_state` or `PDAF_assimilate_X` (with X being the name of a filter algorithm) to get the number of time steps to be computed in the forecast phase.
    610
    711The interface is the following:
    812{{{
    9 SUBROUTINE U_next_observation(stepnow, nsteps, doexit, timenow)
     13SUBROUTINE next_observation_pdaf(stepnow, nsteps, doexit, timenow)
    1014}}}
    1115with
     
    2125Some hints:
    2226 * If the time interval between successive observations is known, `nsteps` can be simply initialized by dividing the time interval by the size of the time step
    23  * At the first call to `U_next_observation` the variable `timenow` can be initialized with the current model time. At the next call a forecast phase has been completed. Thus, the new value of `timenow` follows from the time interval for the previous forecast phase.
     27 * At the first call to `next_observation_pdaf` the variable `timenow` can be initialized with the current model time. At the next call a forecast phase has been completed. Thus, the new value of `timenow` follows from the time interval for the previous forecast phase.