[MITgcm-support] non-periodic forcing files
quentinjamett at gmail.com
Mon Sep 25 15:02:46 EDT 2017
Dear MITgcm users,
I have made some modifications in the code to force a model with forcing
files that are made as sub-samples (in time) of longer time series. This
avoid the use of too large forcing files, and, I think, speeds up the
reading, which becomes interesting when the model is integrated on a
platform with a time limit. It might be of interest for some of you.
The idea is to use periodicExternalForcing=.TRUE., and to modify the
interpolation in time made at the beginning and at the end of a cycle.
Then, externForcingCycle corresponds now to the length of a sub-sample,
and externForcingPeriod is the usual time step between time records.
Instead of interpolating data between the last and the first time record
at the beginning and at the end of a cycle, the interpolation is now
made between the third last and the second last time record at the end
of a cycle, and between the last and the first time record at the
beginning of a cycle. This is made by setting useYearlyField=.TRUE. in
data, &PARM03. Forcing files have to be extended accordingly, with 2
additional time records placed at the end, the last (second last)
corresponding to the last (first) time record of the preceding
These modifications are made in get_periodic_interval.F, where two
global model parameters are added as input: nIter0 and useYearlyField.
- nIter0 is used to discriminate if the interpolation is made between
the last and the first time record at the very first model time step
within a cycle, or between the third last and the second last time
record at the very last model time step within a cycle.
- useYearlyField (defined in PARAMS.h, and set by default to .FALSE. in
set_defaults.F) allows to switch from periodic to non-periodic
(sub-sampled) forcing files.
All files that CALL GET_PERIODIC_INTERVAL have to be modified
accordingly. A specific flag 'useYearlyField_xxx' can be defined for
Modified files are available here:
Feel free to comment/update/share.
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