Changes between Version 12 and Version 13 of PDAF3_new_functionality


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Timestamp:
May 31, 2025, 7:44:48 AM (4 days ago)
Author:
lnerger
Comment:

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  • PDAF3_new_functionality

    v12 v13  
    3333We added a module for observation diagnostics in PDAF-OMI. With this, there are routines that provide the user-code - usually prepoststep - direct access to the observation information (observation vector, observed ensemble, observed ensemble mean, observation coordinates, observation error variances). There are also routines that compute statistics between the observation vector and the observed ensemble mean for example, for the root mean square difference, correlation, bias, and mean absolute error. The statistics can be used, e.g., to plot a Taylor diagram.
    3434
    35 Further information: [wiki:PDAFomi_observation_diagnostics PDAFomi observation diagnostics]
     35This functionality can be used with the new option to initialize observations before the routine prepoststep_pdaf is called for the forecast ensemble. With this one can apply the observation diagnostics to compare the observations to become assimilated with the forecast ensemble.
     36
     37Further information: [wiki:#Initializingobservationsbeforeprepoststep_pdaf]
    3638
    3739=== New routines to set parameters for PDAF ===
    … …  
    4749Further information: [wiki:PDAF3_interface The PDAF3 interface].
    4850
     51=== Intializing observations before prepoststep_pdaf ===
     52
     53By default observations are initialized just before the analysis step after `prepoststep_pdaf` is called.
     54In the PDAF integer options that are set in the call to `PDAF_init` or with the new `PDAF_set_iparam`, the option with index 9 (`type_obs`) allows to switch the initialization of observation to happen before the routine prepoststep_pdaf is called. This allows to compare the observations with the forecast ensemble, e.g. using the new PDAF-OMI observation diagnostics
     55
     56Further information: [wiki:AvailableOptionsforInitPDAF Available options for the different DA methods]
     57
    4958=== Using `PDAF3_assimilate` in flexible parallelization mode ===
    5059
    5160In the flexible parallelization mode of previous PDAF versions, one had to use `PDAF_put_state` for the flexible parallelization mode. With PDAF V3 it is possible, and recommended, to use `PDAF3_assimilate` instead. This functionality is used in combination with calling the new routine `PDAF_get_fcst_info`.
    5261
    53 Further information: [wiki:ExternalModelLoop Modification of the model code for the 'flexible' ensemble integration].
     62Further information: [wiki:OnlineFlexible_PDAF3 Modification of the model code for the 'flexible' ensemble integration].
    5463
    5564
    … …  
    6877=== Initializing observations before `prepoststep_pdaf` ===
    6978
    70 In PDAF V3, one can choose to initialize observations after an forecast phase before the routine prepoststep_pdaf is called. This is set using the integer parameter with index 9 (see [wiki:AvailableOptionsforInitPDAFinPDAF3 Options for PDAF_init]). This option allows the to assess observation information in `prepostep_pdaf` to compare the forecast ensemble with the observations that will be assimilated in the following analysis step, e.g. using the new PDAFomi observation diagnostics.
     79In PDAF V3, one can choose to initialize observations after an forecast phase before the routine prepoststep_pdaf is called. This is set using the integer parameter with index 9 (see [wiki:AvailableOptionsforInitPDAFinPDAF3 Options for PDAF_init]). This option allows the to assess observation information in `prepostep_pdaf` to compare the forecast ensemble with the observations that will be assimilated in the following analysis step, e.g. using the new [wiki:#PDAF-OMIobservationdiagnostics PDAFomi observation diagnostics].
    7180
    72 Further information: [wiki:AvailableOptionsforInitPDAFinPDAF3 Options for PDAF_init] and [wiki:PDAFomi_observation_diagnostics PDAFomi observation diagnostics]
     81Further information: [wiki:AvailableOptionsforInitPDAF Options for PDAF_init] and [wiki:PDAFomi_observation_diagnostics PDAFomi observation diagnostics]
    7382
    7483=== Calling the analysis step in offline coupling with `assim_offline` ===
    … …  
    7685For the offline coupled mode in PDAF2, one used `PDAF_put_state` routines in combination with `PDAF_set_offline_mode`, which switched off the ensemble integration functionlity (in older code version one used `subtype=5`). In PDAF3, there are now `PDAF_assim_offline` routines, e.g. `PDAF3_assim_offline`, which can be directly called after the PDAF initialization. This simplifies the code for the offline mode, since only a call to `PDAF_init` followed by `PDAF3_assim_offline` are required.
    7786
    78 Further information on the offline coupling: [wiki:OfflineImplementationGuide Implementation Guide for Offline Mode]
     87Further information on the offline coupling: [wiki:OfflineImplementationGuide_PDAF3 Implementation Guide for Offline Mode]
    7988
    8089=== Setting random number seed in PDAF ===