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WorkingGroups/DataAssimilation – NEMO

Version 11 (modified by nicolasmartin, 5 years ago) (diff)


Assim WG

Last edition: Wikinfo(changed_ts)? by Wikinfo(changed_by)?

Working group leader: Eric Blayo.
In charge of these wiki pages: Dan Lea and Kristian Mogensen

Members of the Working group:

  • M. Balmaseda (ECMWF)
  • R. Benshila (CNRS)
  • E. Blayo (LJK, U. Grenoble)
  • P-A. Bouttier (LEGI, LJK and NEMO Team, CNRS)
  • P. Brasseur (LEGI, CNRS)
  • C. Ethe (NEMO Team, CNRS)
  • D. Lea (UK Met Office
  • C. Levy (NEMO Team, CNRS)
  • G. Madec (LOCEAN and NEMO Team, CNRS)
  • K. Mogensen (ECMWF)
  • E. Rémy (Mercator Océan)
  • J. Verron (LEGI, CNRS)
  • A. Vidard(INRIA)
  • J. Waters (Met Office)
  • A. Weaver (CERFACS)
  • K. Haines (Univ. Reading)
  • S.Masina (CMCC)
  • S. Dobricic (CMCC)
  • A. Storto (CMCC)
  • M. Martin (Met office)


Definition of several priorities and to the development of several bricks of a NEMO assimilation component


See annual reports in attached documents:

Report for the 2016 Working Plan

The NEMO-ASSIM group was created with the aim of sharing scientific and technical expertise about Data Assimilation (DA) with NEMO, and to identify priorities for developing NEMO components required to easily interface the model code and various DA systems.

Originally, the NEMO-ASSIM membership was established on the basis of contributions from members representing various institutes actively involved in DA systems based on NEMO. A first report (Bell et al, 2009) outlined the scope of the mission of the working group. A report on first achievements was published in 2012 (Bouttier et al., 2012), and a generic concept for the NEMO-ASSIM built-in, interface and external components was proposed from the perspective of long-term developments.

Following advices from the NEMO-ASSIM group, three components were implemented into NEMO: the observation operator OBS, the increment application operator (ASM) and the linear tangent and adjoint models (TAM). This year, a reference configuration for DA, called SEABASS, will be set up to demonstrate how these tools work and to help new users to take in hand the DA interfaces.

Briefly speaking, considering the progress made during the past 5 years, we would like to give a new impetus to the NEMO-ASSIM working group in order to:

  • Consolidate the concept of NEMO-ASSIM as outlined here above,
  • Gather broader scientific and technical expertise based on a larger variety of DA systems that could be interfaced with NEMO
  • Recommend and implement essential developments to be integrated in the NEMO system core that will facilitate interfaces between NEMO and a number of DA systems in use today.

Several implementations of DA with NEMO have been performed in the past few years, which are not currently represented in the NEMO-ASSIM working group. This was confirmed during the last NEMO-ASSIM meeting which has taken place in January 2015.

In that context, we plan to set up this year a new NEMO-ASSIM working group, smaller than before (around ten persons) with clear objectives which will be written in a terms of Reference document that will be diffused in the next weeks. This group will communicate development recommendations to the NEMO community each year, following the NEMO development agenda.

In 2015, the nemo_v3_6_STABLE version has been released, focused on the CMIP6 needs. The next version of NEMO is underway now, and will include a major “simplification and robustness” work.

On our working group side, the new impetus announced here will allow us to set up recommendations and actions for data assimilation in this next NEMO release.
The aim for 2016 will be to discuss and build actively these recommendations and list of actions, but no development action for this year.

However, given the major "simplification and robustness" work which will occur this year, this new working group could review the major code modifications and their impact on the existing or potential data assimilation components. This task could be done by identified people from the new working group members.

Also, the reference configuration for Data Assimilation, SEABASS, available in the NEMO v3.4_STABLE version is recommended to be integrated as a test case for 2016, given the fact that this configuration has been used with a various range of DA systems and results are available.

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