WikiPrint - from Polar Technologies

The user only needs to edit the experiment.wrf4g file in order to design the experiments. From this file WRF4G generates all the WRF configuration files (namelist.wps and namelist.input) needed to run the simulations planned for the experiment, and then launchs them. The namelist.input files are constructed modifying the default namelist provided by NCAR with WRF source code. experiment.wrf4g has the following structure:

experiment variables

Domain of simulation

Input data

Output data

Experiment time-specification


Parallel configuration

WRF-namelist parameters

User provided namelist values. They will be over-written on multiple_parameters experiments (only the included parameters). User can modify any of the parameters of the namelist. The name must be the same of the namelist.input entry, with a prefix-flag and the record to where belongs.

Note that the namelist variables already present in the default namelist.input do not need to be provided with _ _[record].



Multipledates runs

When the multiple_dates parameter is set to 0, two additional configuration options (simulation_interval_h and simulation_lenght_h) are available to set up hindcast runs. Their usage is best understood through a couple of examples. Imagine you are interested in running a 7-day forecast starting every day at 12Z for the period from 1-Jan-2001 to 31-Dic-2001. This can be accomplished by setting:

start_date = "2001-01-01_12:00:00"
end_date = "2002-01-01_00:00:00"
is_continuous = 0
  simulation_interval_h = 24
  simulation_lenght_h = 168 # this is 7 days in hours

and the wrf4g_submit will setup 365 independent runs performing the 7-day forecasts, which will be distributed in the grid or in your local cluster.

Multipleparameters runs

Multi-physics runs are activated when the multiple_paramters parameter is set to one. Three additional parameters allow you to configure the physics combinations of your interest.

This mode allows varying parameters in general, not necessarily physics options. For instance, if user could be interested in checking WRF performance on domain MPI-decomposition, by settting:

is_multiphysics = 1
  multiphysics_variables = "nproc_x,nproc_y"
  multiphysics_nitems = "1,1"
  multiphysics_combinations = "1,4/4,1/2,2/-1,-1"

you can vary the domain decomposition and send an experiments with four realizations, and the only difference is the way the MPI domains are partitioned.