Differences
between the GEM and GEMCLIM (GEM in climate mode)
The big differences between climate and non-climate mode are 1) the
automatic
re-launching of a multi-month job, 2) the large amount of pre-
and post-processing that
will
be done: automatic testing/setting of several of the model
run-time
variables, creation of part of the config files
and production of a comprehensive set of diagnostics,
following WCRP and AMIP2 guidelines. This implies that, if diagnostics
are
requested (strip_phy=1
and diagnos=1),
the output variable/timesteps definition file 'outcfg.out' will be
created
automatically. In this case the output interval is determined by the
parameter 'MOYHR'
in your
'gemclim_settings.nml'. But it is still
possible to add
extra output
variables to
it.
The model output is written
directly into the directory ${EXECDIR}/output/current_last_step/tile instead of in
${EXECDIR}/${REPRUN}/tile to
avoid unnecessary data moving, where 00-00
would denote the first tile. The 16-bit turbo compression algorithm is
turned ON by default.
In climate mode the zonal-mean O3
climatology suggested by the AMIP2 experimental protocol is
used.
If you
want to use another O3
climatology you need to call this file 'ozoclim' and
place it in the
directory from which you launch the model. You will also
have
to provide appropriate litozon2.ftn
and ozopnt.cdk source files
and re-generate
a new model executable with them.
Basically everything that was before called 'gem' or 'gemdm' is now
called
'gemclim'. See running
GEMCLIM short
version.
The physic tendencies and accumulators
get
reset to zero each time they have been written as requested in the file
'outcfg.out'. This can cause problems when outputting time series.
Therefore, if an accumulator is requested for time series output it
also
needs to requested for in the file 'outcfg.out'
at the same frequency.
The accumulated variables that will be reset can be found in
the physics source file 'acclist.cdk'.
The pressure level under which there are no clouds considered to be is raised
from 70 hPa to 100 hPa (set in 'nocld.cdk').
The minimum wind strength
is changed from 1.0E-04 m2/s2
to 6.25 m2/s2
when using the Force-Restore surface scheme. This is the same value
that ISBA is using (set in 'vamin.cdk').
The moving/treatment of the model
output can be started during the run at every multiple of number
of days specified in 'climat_cleanup'
in
your 'configexp.dot.cfg'.
The time series will be
written in version 2.00 format. The differences with the previous format of the time series
which is still written in non-climate mode are:
- The HH record,
containing the time information, is written in double precision.
- The HY record,
containing the vertical grid information (p_top, p_ref, coef), is added.
- The etiket
has 12 characters and surface and profils variable names can have 4 characters.
- Account for accumulators
in case they were not reset every time series output time step.
- A few more variables
are available for time series output.
- The program ts2tab can be used to transform
the RPN standard time
series files into ASCII tables.
In case of problems you might find help in our little trouble
shooting.
Author: Katja Winger
Last update: May 2008