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2010WP/2010Stream3 – NEMO
wiki:2010WP/2010Stream3

Version 9 (modified by cbricaud, 14 years ago) (diff)

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2010 Stream 3


Last edited Timestamp?



S 3.1 : from LOCEAN-NEMO team


S3.1-a — Title

Motivation: ....
Status : ....
main tasks : ....
(1) ...

(2) ...

Principal Investigator : name (email adress)


From NOCS-NEMO team (short-term) ==

S1.0-a - User Interface

Motivation: Shared daily support to users, web & paper documentation. A reduction in the Paris system team this year will necessitate greater sharing of these responsibilities between the disptributed system team members
Principal Investigator : Andrew Coward (acc@…)

S1.5-a - Review of new documentation

Motivation: The exchange and proof-reading of new documentation between system team sites before release should ensure consistency of style, readability and accuracy.
Status : Carried over from 2009 but expected to start as soon as new documentation is submitted.
Principal Investigator : Steven Alderson (sga@…)


S3.2-a — Revisit of mass and salt fluxes between ice, ocean and air

Motivation: As a consequence of the embedding of sea-ice into the ocean (see S3.2-b), the total mass of salt of the combined sea-ice/ocean system is conserved by removing a volume of water from the ocean when ice forms or adding a volume of water when it melts. When ice forms, salt contained in the water is returned to the ocean, less the salt retained in the ice itself. When ice melts, the salt contained is added back to the ocean. (NOCS team, 3wk)
Status : Carried over from 2009 but work is well advanced. Full testing and documentation will be complete for 3.3 release
Principal Investigator : Yevgeny Aksenov (yka@…)

S3.2-b — Embedding sea-ice inside the ocean

Motivation: Replace the unrealistic 'levitating' ice
Main task:
(1) To improve the coupling between the sea-ice and ocean models, we embed the sea-ice into the ocean by changing the volume of the ocean and depressing the ocean interface by a depth equal to the mean ice draft. The latter is calculated as the water equivalent of the total ice and snow mass in the model grid box using in-situ local densities of seawater. The pressure gradient that takes into account the total weight of sea ice and snow in the top model grid box is added to the ocean momentum budget. The vertical coordinate is redefined for the whole water column. (v3.3) (NOCS team, 4wk)
Status : During 2009 the above scheme was implemented and tested at NOCS in a 100-year long integration of an ORCA2-LIM2 configuration using both linear and non-linear free surface options. It was also tested for short runs in the ORCA2-LIM3 configurations. A longer run in ORCA2-LIM3 will take place early in 2010 and the code committed for the NEMO 3.3 release.
Principal Investigator : Yevgeny Aksenov (yka@…)

S3.2-c — Embedding sea-ice inside the ocean for CICE

Motivation: Similar changes will have to be made in order to fully embed CICE-modelled sea-ice. Subtle differences and problems may arise because of the B-grid basis of CICE. This work is listed separately to ensure that possible delays will not impact on the delivery of an embedded solution for LIM (v3.3) (NOCS team, 3wk)

Principal Investigator : Yevgeny Aksenov (yka@…)

S3.2-d — Lateral ocean physics

Motivation: Griffies's implementation of the Gent and McWilliams? eddy transport as a skew flux is being implemented. This has the advantage that its numerical discretization can be written in terms of contributions from quarter cells – ‘triads’. This gives a tighter stencil, disallowing 2-gridpoint numerical noise that is permitted by the advective discretization.
Main task:

(1) Discretise Isopycnal diffusion in terms of these triads. This will obviate the need to smooth isopycnal slopes horizontally with a Shapiro filter (as currently implemented in NEMO), or to apply a background horizontal diffusivity that mixes diapycnally.
(2) Implement Visbeck et al.'s formulation of spatially varying diffusivities as an alternative to the current formulation based on the Held and Larichev timescale and the Rossby radius as a lengthscale.
(3) Add a slope limiting algorithm (mixed-layer depth is sensitive to the slope limiting that is employed) that behaves satisfactorily within and immediately below the mixed layer. (v3.3) (NOCS team, 4wk)

Status: A working prototype code for the iso-neutral and skew-flux operator was carefully reviewed in 2009. Considerable care has been taken in the formulation to ensure the tensorial representation is consistent with the variable volume layers (S-coordinate/z* representation). This has been documented and will be provided with the release.
Principal Investigator : George Nurser (agn@…)

S3.2-e — Improved thermodynamics for LIM3

Motivation: Enhancement of lateral melting paramerisations
Main task:

(1) New parameterisations for lateral melting processes will be incorporated including parameterisations for the effects of waves on fragmentation and melting. (NOCS team, 8wk)

Principal Investigator : Yevgeny Aksenov (yka@…)

S3.2-f — Rationalisation of support for ORCA configurations

Motivation: A cleaning and enhancement of code support for global (ORCA) configurations is required to introduce configurations in common use across the community.
Main task:

(1) Support will be improved or added for ORCA1, ORCA05, ORCA025 and ORCA_R12 configurations in such a way that multiple vertical resolutions of each can be maintained.
(2) The use of .h90 files will also be suppressed. (NOCS team, 4wk)

Principal Investigator : Andrew Coward (acc@…)

S3.2-g — Improvement of numerical treatment for vertical diffusion

Motivation: An improvement in the numerical treatment of vertical diffusion can be achieved by replacing the fully implicit scheme with a Crank-Nicholson scheme. This approach is widely used in other ocean models (e.g. ROMS) and can be implemented relatively simply.
Main task:

(1) The replacement scheme will be implemented and its performance tested.
(2) A similar scheme will also be implemented for the bottom friction contribution to the barotropic momentum trend in dynspg_ts. (NOCS team, 1wk)

Principal Investigator : Andrew Coward (acc@…)

S3.2-h — Implementation of the Neptune effect parameterisation

Motivation: The Neptune effect (Holloway 1992) is a well established parameterisation of the interaction of eddies with topography. The parameterisation is often seen as essential in Arctic ocean simulations even in high resolution models.
Main task:

(1) Add the parameterisation to the reference code
(2) Test, document and report (v3.3) (NOCS team, 5wk)

Principal Investigator : Jeff Blundell (jeff@…)

S3.2-h — Implementation of spectral nudging

Motivation: Work by our Canadian colleagues has demonstrated the potentail benefits of spectral nudging techniques to restore large scale gradients without suppressing meso-scale activity.
Main task

(1) The v2.3 solution will be obtained and implemented in the reference code (v3.3) (NOCS team, 6wk)

Principal Investigator : Jeff Blundell (jeff@…)


S 3.3 : from MERCATOR-NEMO team


S3.3-a — ECUME bulk formulation

Motivation: ability for NEMO to use another bulk formulation for heat, humidity and momentum at the air/sea interface based on multi-campaigns in situ measurements
Status : development and phasing with nemo3.2_beta ok (done in 2009)
main task: doc and nvtk will be done (3w)
Principal Investigator : Gilles Garric (ggarric@…)

S3.3-b — Vertical scheme

Motivation: Mellor Yamada 2,5, generic length scale (Umlauf and burchard 2003) +boundary conditions(Craig and Banner)
Status : Running on NEMO_2.3; development on NEMO_3.2
main tasks :Phasing, nvtk and doc (5w)
Principal Investigator : Guillaume Reffray (greffray@…)

S3.3-c — Lagrangian Floats Module: Validation, Improvements ( IO in Netcdf)

Motivation: Online monitoring of water particles (position + (T,S) signature), improvements of ascii output + implementation of I/O Ariane (B Blanke) convention: on-mesh initialisation+ netcdf outputs
Status : OK for NEMO 2.3
main tasks : Phasing, nvtk and doc (3w)
Principal Investigator : stephane LAW CHUNE (slaw@…)

S3.3-d — resolving the 2 versions of time-stepping

Motivation: Tracer conservation and time splitting. reference: Shchepetkin, A. F., and J. C. McWilliams?, 2005
Status :NVTK OK. commit early 2010
main tasks : Documentation is missing (2w)
Principal Investigator : Jerome Chanut (jchanut@…)

S3.3-e — Mixed Implicit/Explicit? bottom friction

Motivation: Unconsistent bottom stress in 2d and 3d modes. From BOM code. Explicit bottom stress in barotropic equations/implicit in baroclinic equations ....
Status :Ready. Need to iterate with Gurvan with respect to recent implementation of explicit bottom friction. comit: Mid 2010
main tasks : phasing, nvtk and doc(3w)
Principal Investigator : Jerome Chanut (jchanut@…)

S3.3-f — Misceallenous: Log bottom friction

Motivation:Add Logarithmic bottom friction for tidal applications
Status : Development OK. comit: Mid 2010.
main tasks : phasing, nvtk and doc(3w)
Principal Investigator : Jerome Chanut (jchanut@…)

S3.3-g — two bands solar penetration scheme with climatological KPAR attenuationcoefficient.

Motivation: More simple and cheaper than 4 bands attenuation scheme (Rochford et al, JGR 2001. Uses climatological KPAR, 2 bands attenuation.)
Status :Development OK. comit: Mid 2010
main tasks : phasing, nvtk and doc(3w)

Principal Investigator : Jerome Chanut (jchanut@…)


S 3.4 : from Met Office-NEMO team


S3.4-a — Title

Motivation: ....
Status : ....
main tasks : ....
(1) ...

(2) ...

Principal Investigator : name (email adress)

...