GEM model output

All model "data" output is written in RPN standard files.

There are different types of data the model can output:

• "normal" 2-D and 3-D output
• Time series (station data)
• Zonal means (rarely used)
• Pilot files
• Analysis files

Click on the following link for a description of the most common variables:  variable dictionaries

The model will also save these other files:

• Listings
• Restart files
• Jobs

All  files above are stored in 'machine:directory' as specified by 'CLIMAT_arch_mach' and 'CLIMAT_archdir' in the file 'configexp.cfg'.
The files are organized into the following subdirectories:

And then you should also have this file:
     maingemdm_Linux_x86-64.Abs 
or
     maingemdm
which is a copy of the executable.

2-D and 3-D output

There are four types of output files:

Direct model output (Samples)
All fields requested in 'outcfg.out' are written into the four types of output files for the requested frequencies.

Diagnostics
If 'CLIMAT_diagnos=1' in 'configexp.cfg' the model output will get further processed.
The diagnostics contain:

• monthly means and variances calculated for all model output fields
• 2-D time series for selected fields (if requested and available)

Time series

In addition to the general 2-D and 3-D output, GEM/GEMCLIM can output time series at selected grid points (stations).

Requesting time series

A few parameters need to be added to the config-file 'gemclim_settings.nml' to output time series. These parameters are are part of the namelist 'gem_cfgs':

Note: Whenever asking for accumulators in time series output, one needs to also ask for them as 2-D fields in the regular output in the file 'outcfg.out' with the same output frequency. Otherwise they will never get reset to zero but accumulate forever!

Looking at time series

Although the time series are written in RPN standard format you will not be able to look at them with 'xrec' or to use 'r.diag' or 'editfst'. But you can have a look at the content using 'voir'.

There is also a program called 'ts2tab' which converts the RPN standard file time series into ASCII files.

Zonal means

Similar to requesting time series one can also request zonal means.

Analysis files

Analysis files are used to initialize the model, which is why we also call them "initial conditions".

Environment and Climate Change Canada (and other institutes) uses comprehensive assimilation processes, combining observation data and previous model output to create the analyses files used to initial their weather forecast simulations.

At UQAM we sometimes use our own model output from previous simulations to initialize other simulations. During a model simulation one can automatically output files which can later get used to initialize another simulation by setting the parameter 'CLIMAT_out_anal' in 'configexp.cfg' to the frequency at which one wants to output these initial condition/analysis files. For example for creating monthly initial condition/analysis files set:

     CLIMAT_out_anal="1m"

These files will get archive in the directory named "Analysis". They contain all fields needed to initialize a simulation, using the same surface and microphysics schemes.

Pilot files

Pilot files contain all data needed to to drive a LAM (Limited Area Model) simulation at the lateral boundaries.

Usually we use re-analysis data from other institutes (like ERA5) or analysis data from ECCC or data created by our own simulations. During a model simulation one can automatically output files which can later get used to drive another simulation at the lateral boundaries by setting the parameter 'CLIMAT_out_pilot' in 'configexp.cfg' to the frequency at which one wants to output these driving data. For example for creating 1-hourly pilot files set:

     CLIMAT_out_pilot="1h"

These files will get archive in the directory named "Pilots". They contain all fields needed to drive a simulation at the lateral boundaries.