wiki:WRF4G2.0/Ensemble

Version 18 (modified by carlos, 7 years ago) (diff)

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Ensemble experiments

One of the advantages of using WRF4G is the possibility of defining several types of ensemble case studies in the same experiment to easily compare results between them. Each ensemble section will generate at least one independent realization depending always on the indicated date_time value. This is not only applicable to WRF namelist configurations, it can be perturbed other parameters available in the experiment configuration such as app or namelist_version. Thus, as a result, users can ran WRF simulations with different WRF model versions, execute the same WRF model compiled with different compilers, or check if the same simulation produces the same output on various resources. In order to better illustrate this WRF4G feature, several examples are provided:

  • Example of WRF4G experiment configuration file to set two ensemble sections in which namelist parameters are going to be perturbed.
    [DEFAULT]
    # Experiment configuration
    name                 = test
    # Simulation domain
    max_dom              = 1
    # Experiment time-specification
    #                      start_date          | end_date            | chunk_size_h
    date_time            = 2011-08-28_12:00:00 | 2011-08-30_00:00:00 | 12
    calendar             = standard
    timestep_dxfactor    = 6
    # Running options 
    np                   = 1
    requirements         = ARCH = "x86_64"
    clean_after_run      = yes
    save_wps             = no
    parallel_env         = MPIRUN
    parallel_real        = yes
    parallel_wrf         = yes
    # Vtables must exist as Vtable.[input_extdata]
    extdata_vtable       = GFS
    # Seconds between global analysis input times
    extdata_interval     = 21600
    preprocessor         = default
    postprocessor        = SFC
    domain_path          = /home/user/wrf4g/repository/domains/Santander_50km
    extdata_path         = /home/user/wrf4g/repository/input/NCEP/GFS
    output_path          = /home/user/wrf4g/test/output
    app                  = wrf_all_in_one | bundle | /home/user/repository/apps/WRF/WRFbin-3.4.1_r2265_gfortran.tar.gz
    namelist_version     = 3.4.1
    
    [ensemble/phys1]
    namelist_values      = spec_bdy_width     | 10    
                           spec_zone          | 1    
                           relax_zone         | 9     
                           feedback           | 0     
                           history_interval   | 180   
                           frames_per_outfile | 3     
                           e_vert             | 28   
                           radt               | 15   
                           mp_physics         | 5     
                           cu_physics         | 1    
                           ra_lw_physics      | 1     
                           ra_sw_physics      | 1    
                           sf_sfclay_physics  | 2    
                           bl_pbl_physics     | 2    
                           sf_surface_physics | 2    
    
    [ensemble/phys2]
    namelist_values      = spec_bdy_width     | 10   
                           spec_zone          | 1    
                           relax_zone         | 9     
                           feedback           | 0    
                           history_interval   | 0     
                           frames_per_outfile | 0    
                           e_vert             | 28   
                           radt               | 15    
                           mp_physics         | 4     
                           cu_physics         | 1    
                           ra_lw_physics      | 1     
                           ra_sw_physics      | 1     
                           sf_sfclay_physics  | 1     
                           bl_pbl_physics     | 1     
                           sf_surface_physics | 2     
    
  • Example of WRF4G experiment configuration file to simulate the same WRF experiment using intel and gfortran compilers.
    [DEFAULT]
    # Experiment configuration
    name                 = test
    # Simulation domain
    max_dom              = 1
    # Experiment time-specification
    #                      start_date          | end_date            | chunk_size_h
    date_time            = 2011-08-28_12:00:00 | 2011-08-30_00:00:00 | 12
    calendar             = standard
    timestep_dxfactor    = 6
    # Running options 
    np                   = 1
    requirements         = ARCH = "x86_64"
    clean_after_run      = yes
    save_wps             = no
    parallel_env         = MPIRUN
    parallel_real        = yes
    parallel_wrf         = yes
    # Vtables must exist as Vtable.[input_extdata]
    extdata_vtable       = GFS
    # Seconds between global analysis input times
    extdata_interval     = 21600
    preprocessor         = default
    postprocessor        = SFC
    domain_path          = /home/user/wrf4g/repository/domains/Santander_50km
    extdata_path         = /home/user/wrf4g/repository/input/NCEP/GFS
    output_path          = /home/user/wrf4g/output
    # WRF-namelist parameters. Override namelist.input variables here
    namelist_version     = 3.5.1
    namelist_values      = spec_bdy_width     | 10    
                           spec_zone          | 1    
                           relax_zone         | 9     
                           feedback           | 0     
                           history_interval   | 180   
                           frames_per_outfile | 3     
                           e_vert             | 28   
                           radt               | 15   
                           mp_physics         | 5     
                           cu_physics         | 1    
                           ra_lw_physics      | 1     
                           ra_sw_physics      | 1    
                           sf_sfclay_physics  | 2    
                           bl_pbl_physics     | 2    
                           sf_surface_physics | 2    
    
    [ensemble/intel]
    app                  = wps | command | module load WPS/intel/3.5.1
                           wrf | command | module load WRF/intel/3.5.1
    
    [ensemble/gfortran]
    app                  = wps | command | module load WRF/gfortran/3.5.1
                           wrf | command | module load WRF/gfortran/3.5.1
    
    
  • Example of WRF4G experiment configuration file to execute the same simulation on two computing resources. This obviously involves different path for each resource.
    [DEFAULT]
    # Experiment configuration
    name                 = test
    # Simulation domain
    max_dom              = 1
    # Experiment time-specification
    #                      start_date          | end_date            | chunk_size_h
    date_time            = 2011-08-28_12:00:00 | 2011-08-30_00:00:00 | 12
    calendar             = standard
    timestep_dxfactor    = 6
    # Running options 
    np                   = 1
    clean_after_run      = yes
    save_wps             = no
    parallel_env         = MPIRUN
    parallel_real        = yes
    parallel_wrf         = yes
    # Vtables must exist as Vtable.[input_extdata]
    extdata_vtable       = GFS
    # Seconds between global analysis input times
    extdata_interval     = 21600
    preprocessor         = default
    postprocessor        = SFC
    # WRF-namelist parameters. Override namelist.input variables here
    namelist_version     = 3.5.1
    namelist_values      = spec_bdy_width     | 10    
                           spec_zone          | 1    
                           relax_zone         | 9     
                           feedback           | 0     
                           history_interval   | 180   
                           frames_per_outfile | 3     
                           e_vert             | 28   
                           radt               | 15   
                           mp_physics         | 5     
                           cu_physics         | 1    
                           ra_lw_physics      | 1     
                           ra_sw_physics      | 1    
                           sf_sfclay_physics  | 2    
                           bl_pbl_physics     | 2    
                           sf_surface_physics | 2    
    
    [ensemble/resource_one_member]
    requirements         = HOSTNAME = "resource_one"
    
    [ensemble/resource_two_member]
    requirements         = HOSTNAME = "resource_two"
    
    [resource/resource_one]
    domain_path          = /home/user/repository/domains/Santander_50km
    extdata_path         = /home/user/repository/input/NCEP/GFS
    output_path          = /home/user/test/output
    app                  = wps | command | module load WPS/intel/3.5.1
                           wrf | command | module load WRF/intel/3.5.1
    
    [resource/resource_two]
    domain_path          = /home/user2/repository/domains/Santander_50km
    extdata_path         = /home/user2/repository/input/NCEP/GFS
    output_path          = /home/user2/test/output
    app                  = wps | command | module load WRF/intel/3.5.1
                           wrf | command | module load WRF/intel/3.5.1