PROGRAM fill_inflation_restart

Overview

Utility program to create inflation restart files with constant values.

These files can be used as input for the first step of a multi-step assimilation when adaptive inflation is being used. This allows the namelist items inf_initial_from_restart and inf_sd_initial_from_restart in the &filter_nml namelist to be .TRUE. for all steps of the assimilation including the very first one. (These items control whether inflation values are read from an input file or read from constants in the namelist.)

Adaptive inflation restart files are written at the end of a filter run and are needed as input for the next timestep. This program creates files that can be used for the initial run of filter when no inflation restart files have been created by filter but are required to be read as input.

This program reads the inflation values to use from the &fill_inflation_restart_nml namelist for setting the prior inflation mean and standard deviation, and/or the posterior inflation mean and standard deviation. It does not use the inflation values in the &filter namelist.

This program uses the information from the model_mod code to determine the number of items in the state vector. It must be compiled with the right model’s model_mod, and if the items in the state vector are selectable by namelist options, the namelist when running this program must match exactly the namelist used during the assimilation run.

It creates files with names consistent with the input names expected by filter:

input_priorinf_mean.nc
input_priorinf_sd.nc
input_postinf_mean.nc
input_postinf_sd.nc

An older (and deprecated) alternative to running fill_inflation_restart is to create inflation netcdf files by using one of the NCO utilities like “ncap2” on a copy of another restart file to set the initial inflation mean, and another for the initial inflation standard deviation. Inflation mean and sd values look exactly like restart values, arranged by variable type like T, U, V, etc.

Depending on your version of the NCO utilities, you can use ncap2 to set the T,U and V inf values using one of two syntaxes:

ncap2 -s 'T=1.0;U=1.0;V=1.0' wrfinput_d01 input_priorinf_mean.nc
ncap2 -s 'T=0.6;U=0.6;V=0.6' wrfinput_d01 input_priorinf_sd.nc
-or-
ncap2 -s 'T(:,:,:)=1.0;U(:,:,:)=1.0;V(:,:,:)=1.0' wrfinput_d01 input_priorinf_mean.nc
ncap2 -s 'T(:,:,:)=0.6;U(:,:,:)=0.6;V(:,:,:)=0.6' wrfinput_d01 input_priorinf_sd.nc

Some versions of the NCO utilities change the full 3D arrays into a single scalar. If that’s your result (check your output with ncdump -h) use the alternate syntax or a more recent version of the NCO tools.

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.

&fill_inflation_restart_nml

   write_prior_inf    = .FALSE.
   prior_inf_mean     = -88888.8888
   prior_inf_sd       = -88888.8888

   write_post_inf     = .FALSE.
   post_inf_mean      = -88888.8888
   post_inf_sd        = -88888.8888

   single_file        = .FALSE.
   input_state_files  = ''
   verbose            = .FALSE.
/

The namelist controls which files are created and what values are written to the restart files.

Item

Type

Description

write_prior_inf

logical

Setting this to .TRUE. writes both the prior inflation mean and standard deviation files: input_priorinf_mean.nc, input_priorinf_sd.nc.

prior_inf_mean

real(r8)

Prior inflation mean value.

prior_inf_sd

real(r8)

Prior inflation standard deviation value.

write_post_inf

logical

Setting this to .TRUE. writes both the posterior inflation mean and standard deviation files input_postinf_mean.nc, input_postinf_sd.nc.

post_inf_mean

real(r8)

Posterior inflation mean value.

post_inf_sd

real(r8)

Posterior inflation standard deviation value.

single_file

logical

Currently not supported, but would be used in the case where you have a single restart file that contains all of the ensemble members. Must be .false.

input_state_files

character(:)

List one per domain, to be used as a template for the output inflation files.

verbose

logical

Setting this to .TRUE. gives more output, and is generally used for debugging

Here is an example of a typical namelist for fill_inflation_restart :

&fill_inflation_restart_nml

   write_prior_inf    = .TRUE.
   prior_inf_mean     = 1.01
   prior_inf_sd       = 0.6

   write_post_inf     = .FALSE.
   post_inf_mean      = 1.0
   post_inf_sd        = 0.6

   single_file        = .FALSE.
   input_state_files  = ''
   verbose            = .FALSE.
/

Files

Creates:

input_priorinf_mean.nc
input_priorinf_sd.nc
input_postinf_mean.nc
input_postinf_sd.nc

based on the template file from the specific model this code is compiled for.

References

  • none