Version 8 (modified by laurent, 4 years ago) (diff)

2017 Update NEMO Development Strategy document

Last edited 12/08/16 01:43:33 by vancop

lime

Context and objectives

The NEMO Developer's Committee is responsible for the organisation of an update of NEMO Development Strategy document published in 2014. Objective is to produce a new version of this document in June 2017.
Agenda has been approved 28 June 2016:

  • July to September 2016:
    • Experts identified in the table above to build the preliminary list of questions to discuss (on a wiki page, to be created), and the list of possible contributors
  • September 2016:
    • Comments and additions of these documents by Developer's Committee members
    • Developer's Committee to suggest list of participants for the meeting
  • October 2016: !Agenda and announcement of the meeting in March 2017. (See attached document from J. Le Sommer and M. Bell at the bottom of the page)
  • December 2016: During Developer's Committe meeting, finalize organisation of Development Strategy meeting
  • January to March 2017:Experts listed in table above to draft their chapter
  • March 2017: Development Strategy meeting
  • March to June 2017: Writing and release of new version of Development Strategy document and endorsment from Steering Committee
  • June 2017: Publication of updated NEMO Development Strategy document

Work has been distributed by chapters of the document:

Expert(s) to lead discussions and writing of the chapter
Chapter 1 - Elements of long-term strategy as defined in 2017 → 2022 C. Lévy and writing group
Chapter 2 - Target applications for NEMO by 2022. Julien Le Sommer
Chapter 3 - HPC performance constraints HPC working group
Chapter 4 - Future evolutions of NEMO ocean kernel. Mike Bell
Chapter 5 – Ocean dynamics component of NEMO (including state of the art on subgridscale parametrisations and on tides, see above) Julien Le Sommer
Chapter 6 – Toward locally higher effective resolution: AGRIF Jérôme Chanut
Chapter 7 - The assimilation and ensemble component of NEMO Pierre-Antoine Bouttier and Dan Lea
Chapter 8 - The ice components of NEMO Ed Blockley and Martin Vancoppennolle
Chapter 9 -Air sea interface and surface boundary layer physics Laurent Brodeau
Chapter 10 - The biogeochemical component of NEMO: TOP and its interface Olivier Aumont and Tomas Lovato
Chapter 11 - NEMO validation and range of user support (including user interface to build configurations, and Configuration Manager) Andrew Coward

This page includes a first draft, written by the experts listed above, indentifes for each chapter the points of concensus and the list of subjects to be discussed (with associated list of questions).


Template as starting point for each chapter below:

List of points for which concensus is reached:
(associated actions to schedule, if relevant)

List of subjects in discussion (no concensus yet)
and associated question to lead the discussions next March


Chapter 1 - Elements of long-term strategy as defined in 2017 → 2022 - C. Lévy and writing group

Chapter 2 - Target applications for NEMO by 2022. - Julien Le Sommer

Chapter 3 - HPC performance constraints - HPC Working Group

Chapter 4 - Future evolutions of NEMO ocean kernel. - Mike Bell

Chapter 5 – Ocean dynamics component of NEMO (including state of the art on subgridscale parametrisations and on tides, see above) - Julien Le Sommer

Chapter 6 – Toward locally higher effective resolution: AGRIF - Jérôme Chanut

Chapter 7 - The assimilation and ensemble component of NEMO - Pierre-Antoine Bouttier and Dan Lea

Chapter 8 - The ice components of NEMO - Ed Blockley and Martin Vancoppennolle

Chapter 9 - Air sea interface and surface boundary layer physics - Laurent Brodeau

(In need help on this, mainly been talking to myself, it's incomplete, possibly redundant and not up-to-date, so feel free to correct or PM me about any remark. /laurent)

A Coupling to surface wave-model

First point because it is relevant to almost all the aspects treated in this section.

→ contribution of WG on "wave-model coupling" ?

  • For SBC, both in forced (B) and coupled © mode:
  • better estimate of turbulent air-sea fluxes (bulk transfer coefficients, CD, CE and CH, through better knowledge of the sea surface roughness, like Charnock parameter)
  • more accurate estimate of the momentum flux to the ocean, based on the consideration of the consumption/release of momentum associated with the growth/dissipation of the wave field.
  • For surface boundary-layer physics (D):
  • better estimate of surface/sub-surface TKE injection via "breaking waves", "Langmuir circulation", (+mixing induced by non-breaking waves) that feed TKE and GLS schemes
  • consideration of Stokes-Coriolis forces

B SBC in forced mode

Representation of atmospheric of boundary layer processes.

B.1 Traditional Bulk approach

Consensus reached (at least by Madec & Brodeau):

  • Use more advanced algorithms and forcing functions than CORE, choice of algorithm (NCAR/COARE3.0/COARE3.5/ECMWF)
  • If relevant, use the native cool-skin/warm-layer scheme of the given bulk algorithm to estimate the SSST and use it to compute non-solar heat fluxes (applies to COARE3.X and ECMF algorithms)

→ new sbcblk.F90 and sbcblk_algo_*.F90 based on AeroBulk

see branch "branches/2016/dev_r6711_SIMPLIF_6_aerobulk"

In discussion (no consensus yet):

  • Directly prescribe the wind-stress from the given weather reanalysis product as a SBC instead of computing it with bulk formulae and U10, the surface wind speed (U10 from an reanalysis/forecast already includes the effect of sea surface roughness (waves) and/or current speed)
  • wave model → see A

B.2 Alternatives to the bulk approach

  • coupling to a to a "surface atmospheric boundary layer"-only model
  • coupling to a relatively cheap ACGM with spectral nudging at a specified height
  • ???

C SBC in coupled mode

  • sbccpl.F90 / communication with OASIS needs to become comprehensive
  • What's done in the rest of the code when "ln_cpl==.TRUE." must become consistent with what's done in forced mode.
  • Idea: fake toy bulk atmosphere:

NEMO(ln_cpl_true) ↔ OASIS ↔ Bulk Atm? In which Bulk Atm? is simply a bulk formulae interface that receives the SST from NEMO via OASIS, reads gridded prescribed atmospheric variables, and send computed fluxes via OASIS.

D Surface boundary-layer physics

  • Benefit from a coupled wave mode (see A)
  • Sub-grid closure for ocean surface boundary layer (OSBL) processes :
    • coupling of lateral / vertical parameterizations in the OSBL
    • evolution of TKE/GLS closure, OSMOSIS closure ?
    • parameterization of spatially heterogeneous sub grid convection

Chapter 10 - The biogeochemical component of NEMO: TOP and its interface - Olivier Aumont and Tomas Lovato

Chapter 11 - NEMO validation and range of user support (including user interface to build configurations, and Configuration Manager) - Andrew Coward

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