Changes between Version 1 and Version 2 of next_observation_pdaf
- Timestamp:
- Jan 19, 2015, 9:56:59 PM (10 years ago)
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next_observation_pdaf
v1 v2 1 = U_next_observation=1 = next_observation_pdaf = 2 2 3 The page document the user-supplied call-back routine ` U_next_observation`.3 The page document the user-supplied call-back routine `next_observation_pdaf`. 4 4 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 6 The 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 9 The 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. 6 10 7 11 The interface is the following: 8 12 {{{ 9 SUBROUTINE U_next_observation(stepnow, nsteps, doexit, timenow)13 SUBROUTINE next_observation_pdaf(stepnow, nsteps, doexit, timenow) 10 14 }}} 11 15 with … … 21 25 Some hints: 22 26 * 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.