Version 8 (modified by timgraham, 6 years ago) (diff)

Last edited Timestamp?

Author : Tim Graham

ticket : #1296



Development of a new module to carry out masked damping tracer fields. The mask will be read in from an external netCDF file.

The module will eventually replace the tradmp module in which there are several hard coded options for different grids.



After discussion with Gurvan Madec, reviewer and systems team this task has been changed to modify the existing tra_dmp module rather than replacing it with tra_rlx. The modifications remove all grid dependent options from the NEMO code in line with the NEMO simplification plans.

All of these options (which were in the tra_dmp_init) routine have been moved to an offline tool called DMP_TOOLS. DMP_TOOLS creates a netcdf file containing a 3D field of the restoration coefficient to be used in the model run. This file is now read in by tra_dmp_init. Passive tracer damping (trcdmp.F90) has also been modified to read in a restoration coefficient from a file.

The old behaviour with grid specific settings can be reproduced with the correct namelist options are supplied to the tool (these will be the default in the trunk) and if the tool is run on the same machine (and with the same compiler) as the model then it bit compares with the old version of the code. The netcdf file will be added to the tar files containing standard forcings but this may mean that it does not bit compare on other machines.

DMP_TOOLS takes a NEMO file as input along with a namelist file. It also contains an empty custom module that can be edited by users to create their own restoration coefficient files (e.g. damping in a specific region only).


Testing could consider (where appropriate) other configurations in addition to NVTK].

SETTE Tested '''YES
Other model configurations '''ORCA2_LIM
Processor configurations tested Standard processor configurations
If adding new functionality please confirm that the
New code doesn't change results when it is switched off
and ''works'' when switched on

(Answering UNSURE is likely to generate further questions from reviewers.)

'Please add further summary details here' Using the offline tool to create the damping coefficients for ORCA2_LIM configurations produces identical results to when the tool is compiled on the same machine as the model.

Bit Comparability

Does this change preserve answers in your tested standard configurations (to the last bit) ? '''YES (if dmp_tools compiled/run on same machine as model
Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended) '''YES
Is this change expected to preserve answers in all possible model configurations? '''YES
Is this change expected to preserve all diagnostics?
,,''Preserving answers in model runs does not necessarily imply preserved diagnostics. ''

If you answered '''NO''' to any of the above, please provide further details:

  • Which routine(s) are causing the difference?
  • Why the changes are not protected by a logical switch or new section-version
  • What is needed to achieve regression with the previous model release (e.g. a regression branch, hand-edits etc). If this is not possible, explain why not.
  • What do you expect to see occur in the test harness jobs?
  • Which diagnostics have you altered and why have they changed?Please add details here……..

System Changes

Does your change alter namelists? '''YES
Does your change require a change in compiler options? '''NO '''

nam_tradmp is changed to contain ln_tradmp, nn_zdmp and cn_resto only (cn_resto is the name of the netcdf file containing the restoration coefficient). All other options are now dealt with by dmp_tools. nam_trc_dmp is changed to contain only nn_zdmp_tr and cn_resto_tr only


Minimal changes to model runtime but may require the user to run the tool first.

IPR issues

Has the code been wholly (100%) produced by NEMO developers staff working exclusively on NEMO? '''YES

If No:

  • Identify the collaboration agreement details
  • Ensure the code routine header is in accordance with the agreement, (Copyright/Redistribution? etc).Add further details here if required……….