PROGRAM perturb_single_instance

Overview

Utility program to generate an ensemble of perturbed ensemble member restart files. This program can be run in parallel and used as a stand alone program.

Namelist

This namelist is read from the file input.nml. Namelists start with an ampersand ‘&’ and terminate with a slash ‘/’. Character strings that contain a ‘/’ must be enclosed in quotes to prevent them from prematurely terminating the namelist.

&perturb_single_instance
   ens_size               = ''
   input_files            = ''
   output_files           = ''
   output_file_list       = ''
   perturbation_amplitude = 0.0
   single_restart_file_in = .false.
  /

Item	Type	Description
ens_size	integer	Total number of ensemble members.
input_files	character(len=256),dimension(num_domains)	The restart file you would like to perturb from.
output_file_list	character(len=256)	A file containing a list of the desired output names.
output_files	character(len=256)	An array of filenames
perturbation_amplitude	real(r8)	The desired perturbation amplitude. If the model provides an interface then it will use that subroutine, otherwise it will simply add gaussian noise to the entire state, and this is the standard deviation.
single_restart_file_in	logical	A boolean, specifying if you have a single file restart, such as the case for lower order models.

Below is an example of a typical namelist for the perturb_single_instance.

&perturb_single_instance_nml
   ens_size         = 3
   input_files      = 'caminput.nc'
   output_files     = 'cam_pert1.nc','cam_pert2.nc','cam_pert3.nc'
/

Files

• inputfile.nc (description file that will be perturbed)

• output_file_list.txt (a file containing a list of restart files) and,

• perturb_single_instance.nml

References

• none