Version 9 (modified by flavoni, 5 years ago) (diff)

Last edited Timestamp?

Author : Gurvan Madec, Florian Lemarié, George Nurser

ticket : #1593

Branch : 2015/dev_r5721_CNRS9_NOC3_LDF

WP2015 Action : CNRS-9 and NOC-3


Development branch related to CNRS-9 and NOC-3 actions of 2015 work plan :
• simplify and improve the tracer advection and the lateral diffusion and dissipation in NEMO/OPA
• generalization of the use of surface scale factors (e1e2 at T, U, V, F points)

NB: This development consists in merging the current trunk with the last year work on that subject (see ticket #1260, and the associated branch ​​2014/dev_CNRS0_NOC1_LDF​ and wiki page ​​1260_CNRS0_NOC1_LDF.

(1) define bi-laplacian diffusive operator on dynamics and tracers are re-entrant laplacian ;
(2) change the way the eddy diffusivity and viscosity are specified and controlled by the user ;
(3) generalize of the use of surface scale factors ;
(4) add a optional read of surface scale factors in coordinate file in case of reduction of the scale factors in some straits.

(1) introduce Beckers et al. (2000) compact stencil in the cross-isoneutral direction in triads formalism ;
(2) introduce in both iso-neutral operator the Method of Stabilizing Correction (Lemarié et al. (2012) ;
(3) implement bilaplacian iso-neutral operator (Lemarié et al. (2012).


Three steps:

I. Phasing of horizontal scale factors ==⇒>> OK see revision 5737 )

(I.1) standardisation of the name of quantities derived from horizontal scale factors (many modules of NEMO)
The chosen names of quantities derived from horizontal scale factors are:
- inverse of scale factors : r1_e1t, r1_e2t, r1_e1u, r1_e2u, r1_e1v, r1_e2v, r1_e1f, r1_e2f ;
- surfaces and their inverse: e1e2t, e1e2u , e1e2v, e1e2f and, r1_e1e2t , r1_e1e2u , r1_e1e2v, r1_e1e2f ;
- ratio (used in traldf…) : e2_e1u , e1_e2v(I.1) generalize of the use of surface scale factors ;
These quantities are defined in memory in dom_oce.F90, and set to their proper value in domhgr.F90

(I.2) add a optional read of surface scale factors at velocity points in coordinate file (domhgr.F90)
The input coordinate file have to include e1e2u and e1e2v in case of reduction of the scale factors in some straits.
When e1u or e2v are reduced in some straits, the surface at u- and v-points remains unchanged.
This allows to suppress the dom_vvl_orca_fix routine from dlmvvl.F90 module.
Note that this change modifies the model results, as it contains a better handling of reduced strait width (i.e. reduced surface between 2 adjacent U or V points, but unchanged U and V points volume).
The implementation performed here is a first step to the full simplification of domhgr.F90. We kept here the hard coded reduction of scale factor in some straits for some given ORCA configuration.
A last step (see IV) will be to suppress the hard coded reduction of some scale factor as it will be always given in the file together with the e1e2u & e1e2v surfaces.

II. Phasing of the advective/diffusive trends on tracers


III. Phasing of viscous trends


IV. Finalize the simplification

(IV.1) suppression of hard coded reduction of scale factor in some straits for some given ORCA configuration.
add in NEMOGCM/TOOLS a directory a program that read a file apply a reduction of scale factors in some straits, and create the associated extended coordinates file (
create the extended coordinates files form ORCA 2°, 1°, and 0.5°.

To be CHECKED (not necessary associated with this branch

  • check that task_i use ssmask, i.e. that it takes into account the under ice shelf seas.
  • CRS : the new arrays derived from horizontal scale factors MUST be added in CRS.
  • Bug in diawri.F90 when NOT using key_iomput (OK =⇒> see ticket #1596)
  • Idea for finalization of domhgr.F90 :
    add 2 modules (from domhgr.F90), domhgr_read.F90 and domhgr_ana.F90, which contains:
    - domhgr_read.F90: the CASE jphgr_msh=0 of domhgr.F90 (i.e. read the coordinates file)
    - domhgr_ana.F90: the CASE jphgr_msh=5 of domhgr.F90 (i.e. the GYRE analytical definition of the coordinates)
    add in NEMOGCM/TOOLS a directory containing 3 domhgr_ana.F90 modules associated with (1) a geographical mesh on the sphere with regular (in degree) grid-spacing (jphgr_msh=1) ; (2) f- or beta-plane with regular grid-spacing (jphgr_msh=2 or 3)) ; (3) geographical mesh on the sphere, isotropic MERCATOR type (jphgr_msh=4)
    remove from the namelist_ref/namdom all variable related to the horizontal mesh, and add a flag, ln_mesh_read, =T read the file ; =F analytical mesh (by default GYRE mesh).


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

NVTK Tested '''YES/NO'''
Other model configurations '''YES/NO'''
Processor configurations tested [ Enter processor configs tested here ]
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'

  • Processor configurations tested
  • etc——

Bit Comparability

Does this change preserve answers in your tested standard configurations (to the last bit) ? '''YES/NO '''
Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended) '''YES/NO'''
Is this change expected to preserve answers in all possible model configurations? '''YES/NO'''
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/NO '''
Does your change require a change in compiler options? '''YES/NO '''

If any of these apply, please document the changes required here…….


''Please ''summarize'' any changes in runtime or memory use caused by this change……''

IPR issues

Has the code been wholly (100%) produced by NEMO developers staff working exclusively on NEMO? '''YES/ NO '''

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……….