New URL for NEMO forge!   http://forge.nemo-ocean.eu

Since March 2022 along with NEMO 4.2 release, the code development moved to a self-hosted GitLab.
This present forge is now archived and remained online for history.
2017UpdateNEMOStrategy/FirstSteps (diff) – NEMO

Changes between Version 16 and Version 17 of 2017UpdateNEMOStrategy/FirstSteps


Ignore:
Timestamp:
2016-12-08T01:32:46+01:00 (8 years ago)
Author:
vancop
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • 2017UpdateNEMOStrategy/FirstSteps

    v16 v17  
    6060== Chapter 3 - HPC performance constraints - HPC Working Group == 
    6161Please see the attached word document [https://forge.ipsl.jussieu.fr/nemo/attachment/wiki/2017UpdateNEMOStrategy/FirstSteps/NEMO_Development_Strategy_HPC_questions.docx] 
     62 
    6263== Chapter 4 - Future evolutions of NEMO ocean kernel. - Mike Bell == 
    6364== Chapter 5 – Ocean dynamics component of NEMO (including state of the art  on  subgridscale parametrisations and on tides, see above) - Julien Le Sommer == 
    6465== Chapter 6 – Toward locally higher effective resolution: AGRIF - Jérôme Chanut == 
    6566== Chapter 7 - The assimilation and ensemble component of NEMO - Pierre-Antoine Bouttier and Dan Lea == 
    66 * Establish an identity for the NEMO DA community 
    67    - Create a list of NEMO users working on DA or using the assimilation interface for other purposes (for example model validation compared to observations). This would be held on WG wiki or the NEMO website. 
    68    - Keep the wiki regularly updated 
    69    - Create a NEMO DA mailing list 
    70 * The future of NEMO-TAM and whether and how it is kept up to date with model updates is a question the DA WG will consider. No recommended actions currently. This will be reviewed at future WG meetings. 
    71 * Ensemble mode. There is an increasing interest in the data assimilation community for using ensemble information in data assimilation. 
    72    - Many group members would find a single executable approach useful for running all the ensemble members. This requires an MPI communicator for the sub-domains of each ensemble member and another MPI communicator for passing information between ensemble members. 
    73 * Higher resolution modelling 
    74    - Improve the efficiency of the assimilation interface code (OBS and ASM) 
    75    - Deal correctly with observations which are spread over several model grid cells (i.e. have a "footprint") 
    76 * NEMO-OBS package 
    77    - If the above ensemble mode is introduce the NEMO-OBS package should be updated to produce ensemble diagnostics. 
    78    - Update the central version of the OBS plotting tool (dataplot) to a new python version 
    79    - Develop some community tools for assessing ensembles which can either go into the TOOLS directory or be made available on the WG wiki or NEMO website. 
     67 * Establish an identity for the NEMO DA community 
     68   * Create a list of NEMO users working on DA or using the assimilation interface for other purposes (for example model validation compared to observations). This would be held on WG wiki or the NEMO website. 
     69   * Keep the wiki regularly updated 
     70   * Create a NEMO DA mailing list 
     71 * The future of NEMO-TAM and whether and how it is kept up to date with model updates is a question the DA WG will consider. No recommended actions currently. This will be reviewed at future WG meetings. 
     72 * Ensemble mode. There is an increasing interest in the data assimilation community for using ensemble information in data assimilation. 
     73   * Many group members would find a single executable approach useful for running all the ensemble members. This requires an MPI communicator for the sub-domains of each ensemble member and another MPI communicator for passing information between ensemble members. 
     74 * Higher resolution modelling 
     75   * Improve the efficiency of the assimilation interface code (OBS and ASM) 
     76   * Deal correctly with observations which are spread over several model grid cells (i.e. have a "footprint") 
     77 * NEMO-OBS package 
     78   * If the above ensemble mode is introduce the NEMO-OBS package should be updated to produce ensemble diagnostics. 
     79   * Update the central version of the OBS plotting tool (dataplot) to a new python version 
     80   * Develop some community tools for assessing ensembles which can either go into the TOOLS directory or be made available on the WG wiki or NEMO website. 
    8081 
    81 == Chapter 8 - The ice components of NEMO - Ed Blockley and Martin Vancoppennolle ==  
     82== Chapter 8 - The ice components of NEMO - Ed Blockley and Martin Vancoppenolle == 
     83There are numerous directions towards which the representation of sea ice could be improved. 
     84 
     85A non-exhaustive and perfectible list would include 
     86 
     87 * sea ice rheology: Towards improving the representation of deformation scaling laws, landfast ice & ice arches. Available approaches to be discussed include 
     88 
     89   * VP-likes vs anisotropic vs elasto-britlle rheologies. 
     90 
     91   * Eulerian vs lagrangian approaches 
     92 
     93 * ice atmosphere coupling: Towards improving the representation of ice-atmosphere interactions, notably in polynya regions or near the ice edge. This would clearly benefit from new possibilities offered by the interactive boundary layer physics. A new approach of coupling via conduction flux in the ice has been proposed at UKMO. 
     94 
     95 * ice thermodynamics: Ice thermodynamics are central because they control the energetic transfer in the sea ice zone. Improvements include better account of 
     96 
     97   * mushy layer thermodynamics (salt & heat conservation, frazil ice, platelet ice) 
     98 
     99   * snow & surface meltwater (melt ponds) physics 
     100 
     101   * radiative transfer (beer law -> delta-eddington schemes) 
     102 
     103 * ice floe size reperesentation. Ice floe size is absent from current sea ice representations in large-scale models. Yet floe size controls lateral melting and wave-ice coupling. Recent works have explored possible ways of improvements. 
     104 
     105 * sea ice biogeochemistry. Sea ice BGC is more of an observational than a modelling problem at the moment. Yet recent studies suggest simple first-order representations of organic matter synthesis in sea ice, carbonate chemistry and carbon fluxes in the sea ice zone. 
     106 
     107Experts suggested: D. Feltham (Reading), T. Fichefet (UCL), D. Salas (Meteo France), 
    82108 
    83109== Chapter 9 - Air sea interface and surface boundary layer physics - Laurent Brodeau, Gurvan Madec == 
    84110Please see [https://docs.google.com/document/d/14tj6jZEgqXhVp1n1_IcZJn4XMIoT5K76a6Mi8sWFuh4/edit?usp=sharing here!!!] Can't cope with this wiki syntax... 
     111 
    85112== Chapter 10 - The biogeochemical component of NEMO: TOP and its interface - Olivier Aumont and Tomas Lovato == 
    86 * Establish the production of scientifically validated simulations (e.g., validation suite and data repository) to enable the long term assessment of model developments and improvements. 
     113 * Establish the production of scientifically validated simulations (e.g., validation suite and data repository) to enable the long term assessment of model developments and improvements. 
    87114 
    88 * The medium term development of TOP should lead to a general interface for ocean tracers 
     115 * The medium term development of TOP should lead to a general interface for ocean tracers 
     116 
    89117capable to solve all key processes (BC treatment, light in the water column, sinking etc), independently from a specific biogeochemical model. This will translate into a seamless interface where only the core equations of biogeochemical models will be needed to couple with NEMO. 
    90118 
    91 * The uprising complexity of biogeochemical models will require the revision of current HPC approach and the adoption of novel techniques to cope with the increasing computational efforts. In particular, the exploitation of accelerators and GPUs might become a key resource to deal with computational constraints. 
     119 * The uprising complexity of biogeochemical models will require the revision of current HPC approach and the adoption of novel techniques to cope with the increasing computational efforts. In particular, the exploitation of accelerators and GPUs might become a key resource to deal with computational constraints. 
    92120 
    93121== Chapter 11 - NEMO validation and range of user support (including user   interface to build configurations, and Configuration Manager) - Andrew Coward == 
     122 * A clean-up of the configuration set-up routines in NEMO is seen as an essential simplification. This has been started in 2016 and will continue. This process puts greater responsibility on a configuration developer to provide either external input files or user-defined code modules. The system team will endeavour to provide sufficient examples and tools to ease this burden. The benefits are a simpler code kernel which is more suitable for adaptation to future architectures and, ultimately, a less error-prone route to setting up new configurations. Examples and methods need to be well documented and these guides need to be readily available to ease the transition. 
    94123 
    95 * A clean-up of the configuration set-up routines in NEMO is seen as an essential simplification. This has been started in 2016 and will continue. This process puts greater responsibility on a configuration developer to provide either external input files or user-defined code modules. The system team will endeavour to provide sufficient examples and tools to ease this burden. The benefits are a simpler code kernel which is more suitable for adaptation to future architectures and, ultimately, a less error-prone route to setting up new configurations. Examples and methods need to be well documented and these guides need to be readily available to ease the transition. 
     124 * The new interface eases the task of providing simple test cases and the range of such options is expected to grow rapidly. Test cases should be viewed separately to reference configurations but they are useful for demonstrating and comparing numerical schemes; especially when analytical solutions exist for comparison. 
    96125 
    97 * The new interface eases the task of providing simple test cases and the range of such options is expected to grow rapidly. Test cases should be viewed separately to reference configurations but they are useful for demonstrating and comparing numerical schemes; especially when analytical solutions exist for comparison. 
     126 * XIOS-2 should be adopted as default but this still lacks documentation targeted towards NEMO users. The system team should consider compiling an 'XIOS in NEMO' guide detailing relevant settings and tricks for obtaining some of the more complex outputs. Mostly this is a case of documenting the work done to obtain CMIP6 diagnostics. 
    98127 
    99 * XIOS-2 should be adopted as default but this still lacks documentation targeted towards NEMO users. The system team should consider compiling an 'XIOS in NEMO' guide detailing relevant settings and tricks for obtaining some of the more complex outputs. Mostly this is a case of documenting the work done to obtain CMIP6 diagnostics. 
    100  
    101 * A basic but well-tested Configuration Manager (SIREN) is now part of the system. These tools allow a regional sub-model of any ORCA grid to be set up easily. Users will expect such tools for setting up regional models with open boundaries (BDY) and for AGRIF nests; ideally the same tool should be used for both. The UK has made some progress with Python-based tools for constructing regional sub-models from any gridded input. This effort has currently stalled but  is expected to restart next year. The aim should remain to provide a single set of tools for regional model configuration. 
     128 * A basic but well-tested Configuration Manager (SIREN) is now part of the system. These tools allow a regional sub-model of any ORCA grid to be set up easily. Users will expect such tools for setting up regional models with open boundaries (BDY) and for AGRIF nests; ideally the same tool should be used for both. The UK has made some progress with Python-based tools for constructing regional sub-models from any gridded input. This effort has currently stalled but  is expected to restart next year. The aim should remain to provide a single set of tools for regional model configuration.