Customize CICE output

Customize CICE output#

The CICE output can changed with the namelist variables

  • histfreq: Frequency of output written to history files (‘1’, ‘m’, ‘d’, ‘y’, …)

  • histfreq_n: Frequency history data is written to history files

  • hist_avg: if .false. => instantaneous values, if true => time-averages

Here is how to set user_nl_cice to output an extra history file with daily values (leaving the primary history file as monthly):

     histfreq = 'm','d','x','x','x'
     histfreq_n = 1,1,1,1,1
     hist_avg = .true.,.true.,.true.,.true.,.true.

See the CICE Consortium Documentation for the complete namelist.

https://cice-consortium-cice.readthedocs.io/en/main/user_guide/ug_case_settings.html#tables-of-namelist-options

Customize CICE Output#

CICE history output can be customized using namelist variables in user_nl_cice.

The most commonly used variables are:

  • histfreq: Frequency of output written to each history stream.

  • histfreq_n: Number of frequency units between outputs.

  • hist_avg: Controls whether output contains instantaneous values or time averages.

For example:

  • histfreq = 'm' produces monthly output.

  • histfreq = 'd' produces daily output.

  • histfreq = 'y' produces yearly output.

  • histfreq = '1' produces output every model time step.

The corresponding histfreq_n value specifies how many of these units occur between output records.

The variable hist_avg controls whether the output is averaged over the output interval:

hist_avg = .true.

produces time-averaged output, while

hist_avg = .false.

produces instantaneous output.

Creating Additional History Files#

CICE supports multiple history streams. The following example creates an additional daily history file while retaining the default monthly history file:

histfreq   = 'm', 'd', 'x', 'x', 'x'
histfreq_n = 1,    1,   1,   1,   1

In this example:

  • The primary history stream remains monthly.

  • A second history stream is written daily.

  • The remaining history streams are disabled ('x').

Evaluate your understanding

How would you configure CICE to output 6-hourly instantaneous values?

Click here for the solution

Add the following lines to user_nl_cice:

histfreq   = 'h'
histfreq_n = 6
hist_avg   = .false.
Evaluate your understanding

How would you configure CICE to output daily averages?

Click here for the solution
Add the following lines to `user_nl_cice`: 
histfreq   = 'd'
histfreq_n = 1
hist_avg   = .true.

Note

At the time of this tutorial, the CESM3 documentation is still being finalized. CICE namelist options and history-file controls remain very similar to those in CESM2. Therefore, the CESM2 CICE documentation remains a useful reference for understanding and customizing CICE output. Also, the CICE Consortium documentation is a valuable resource.

Note

Increasing the output frequency or enabling multiple history streams can substantially increase model output volume and reduce throughput. Output only the variables and frequencies needed for your analysis.

For additional information about CICE history output and namelist settings, consult the CICE Consortium documentation.

https://cice-consortium-cice.readthedocs.io/en/main/

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