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Data Assimilation (DA-TT)


The DA-TT brings together experts in the field from leading operational centres, research institutions, and groups from academia in a shared dialog about the current state-of-the-art, and common challenges faced by the ocean Data Assimilation (DA) community. The primary vehicles are regular workshops and collaborative activities. Since DA is an essential and common thread to many of the OceanPredict goals, an additional role of DA-TT is to catalyse interactions with other TTs.

The DA-TT promotes capacity building in several areas, including: the development of modelling, assimilation, and forecasting approaches and components; demonstrations of accuracy and utility; research value; and intellectual capacity building. The DA-TT also provides a conduit to the broader WMO data assimilation and prediction community. The ocean DA community is small compared to its atmospheric counterpart, and as such, capacity building to meet the current and future demands of the field is an important TT goal. Future DA-TT activities will therefore continue to expand capacity building activities, particularly in relation to intellectual capital, with a view to sustaining an active and vibrant ocean DA community.

The DA-TT is led by the co-chairs:


The DA-TT will foster coordination and monitor progress in activities related to:

  • Development of data assimilation algorithms.
  • Development of coupled data assimilation methods in collaboration with the CP-TT.
  • Assimilation of novel observations (under-utilised existing networks and upcoming missions) in collaboration with the OSEVal-TT and with the MEAP-TT.
  • Assimilation software infrastructure developments and application to new HPC architectures, as related to the adoption of tools developed in the wider data assimilation community which allow enhanced collaborations among operational agencies, research institutes and universities.
  • Performance assessment of data assimilation applications in the operational community, in collaboration with the IV-TT.
  • Application of data-driven algorithms (machine learning and deep learning) for improved pre-processing and exploitation of consolidated and new observing networks.


A major activity of the DA-TT is to organise regular meetings and workshops. In order to increase collaboration, these workshops are often held jointly with other TTs or groups.

The DA-TT coordinates inter-comparison activities aimed at improving our understanding of the operational data assimilation systems used by OceanPredict groups. These have previously included comparison of average increments to understand biases in the ocean models and forcing, and comparison of the impact of observations using idealised, widely spaced observations.

The DA-TT also coordinates contributions to other international activities. We have previously contributed to international conferences such as OceanObs’19 (Moore et al., 2019) and to the 2016 international workshop on coupled data assimilation (Penny et al., 2017).

Moore AM, Martin MJ, Akella S, Arango HG, Balmaseda M, Bertino L, Ciavatta S, Cornuelle B, Cummings J, Frolov S, Lermusiaux P, Oddo P, Oke PR, Storto A, Teruzzi A, Vidard A and Weaver AT (2019). Synthesis of Ocean Observations Using Data Assimilation for Operational, Real-Time and Reanalysis Systems: A More Complete Picture of the State of the Ocean. Front. Mar. Sci. 6:90. doi: 10.3389/fmars.2019.00090.

Penny, S.G., S. Akella, O. Alves, C. Bishop, M. Buehner, M. Chevallier, F. Counillon, C. Draper, S. Frolov, Y. Fujii, A. Karspeck, A. Kumar, P. Laloyaux, J.-F. Mahfouf, M. Martin, M. Peña, P. de Rosnay, A. Subramanian, R. Tardif, Y. Wang, X. Wu. 2017. Coupled Data Assimilation for Integrated Earth System Analysis and Prediction: Goals, Challenges and Recommendations. WWRP 2017-3

Members of the DA-TT


No First name Last name Institutions/projects Country Status
1 Mario Adani CMCC Italy New member (june 2024)
2 Santha Akella  NASA USA Member
3 Hernan Arango  Rutgers University USA Member
4 Ali Aydogdu  CMCC Italy Member
5 Laurent Bertino  NERSC Norway Member
6 Gary Brassington  BoM Australia Member
7 Stefano Ciavatta MOi France Member
8 Marcin Chrust  ECMWF UK Member
9 Bruce Cornuelle  Scripps USA Member
10 Francois Counillon  NERSC Norway Member
11 James Cummings  NRL/NOAA USA Passive Member
12 Pierre De Mey-Frémaux  LEGOS France Member and co-chair of the COSS-TT
13 Sergey Frolov  PSL/OAR/NOAA USA Co-chair
14 Patrick Heimbach  University of Texas at Austin USA Member
15 Collette Kerry  UNSW Sydney Australia New member
16 Young Ho Kim  KIOST South Korea Member
17 Alexander Kurapov Oregon State University / NOAA USA Member
18 Daniel Lea Met Office UK Member
19 Pierre Lermusiaux MIT USA Member
20 Matt Martin  Met Office UK Member
21 Andrew M Moore  UCSC USA Member
22 Lars Nerger AWI Germany New member (15 June 23)
23 Hans N Ngodock  NRL USA Member
24 Paolo Oddo  CMRE Italy Member
25 Peter OKE (TBC)  CSIRO Australia Member ?
26 Arya Paul  INCOIS India Member
27 Pavel Sakov  BoM Australia Member
28 Jozef Skakala  PML UK Member
29 Travis Sluka JCSDA/UCAR USA New member (15 June 23)
30 Gregory Smith  Environment Canada Canada Member and co-chair of the IV-TT
31 Ann Kristin Sperrevick Norway Co-chair
32 Andrea Storto  CMRE/NATO Italy Member
33 Clemente Tanajura  UFBA / REMO Brazil Member
34 Anna Teruzzi  OGS Italy Member
35 Charles-Emmanuel Testut  Mercator Ocean France Member
36 Norihisa Usui  JMA/MRI Japan Member
37 Arthur Vidard  Inria France Member
38 Zhaoyi Wang NMEFC China New member
39 Anthony Weaver  CERFACS France Member

Patron champion:

Johnny Johannessen, NERSC


Status: March 2024

Meetings and workshops

A major activity of the DA-TT is to organise regular workshops. In order to increase collaboration, these workshops are often held jointly with other TTs or groups. Planned and previous workshops include:


Title Date Location Report
DA-TT meeting 9-11 May 2023 Rome, Italy Report
DA-TT/ECMWF workshop 17-20 May 2021 Reading, UK Report
DA-TT workshop 20-22 Jan 2020 Toulouse, France Report
Joint DA-TT & OS-Eval TT workshop 11-13 Oct 2017 La Spezia, Italy Report
Joint DA-TT & MEAP-TT workshop 11-13 July 2016 Santa Cruz, USA Report
DA-TT workshop 20-22 May 2015 Met Office, UK Report

Links below may only be available using a password (please contact the OP programme office for information)


The DA-TT is involved in the ESA A-TSCV project, to work of the assimilation of Total Surface Current Velocity Measurements.

Find out more from the A-TSCV project page.


Meeting reports:

TT Quad-chart

The task team quad-chart provides a quick glance at the TT’s activities, achievements and future plans.


Data Assimilation Task Team (DA-TT) – May 2021
Short description and objectives of the activities started or planned for this year:
Accomplishments of the TT this year:
Main activities:

  • Organise joint ECMWF/OceanPredict workshop on “Advances in Ocean Data Assimilation”.
  • Contribute to the development of the ForeSea programme proposal and relevant UN Decade projects, including SynObs.
Main achievements:

A 4-day virtual workshop was held jointly with ECMWF on “Advances in Ocean Data Assimilation” from 17-20th May 2021:

  • About 180 registered participants from around the world.
  • 2 ½ days of plenary presentations.
  • 2 poster sessions.
  • 1 day of working group discussions.
  • All presentations were recorded and are available, together with the posters and the working group outcomes, from
  • A summary of the workshop and its recommendations will be published in an ECMWF newsletter.
Future plans to continue/ improve current activities:
Issues/ problems:
Main future plans:

  1. Complete the report from the ECMWF/OceanPredict ocean DA workshop and pull through its recommendations into further activities for the DA-TT. These are expected to include, among other things:
  • To start a bi-monthly technical seminar series of the DA-TT to discuss a range of ocean/coupled DA topics in depth.
  • To write a “best practices” article on how to make developments to ocean data assimilation systems for operational forecasting and reanalysis.
  1. Clarify the role of the DA-TT in the UN Decade activities.
  2. Decide on the location and date of the next DA-TT meeting, and whether it will be jointly with another OceanPredict TT.
Main issues:

  • We expect to support UN Decade activities, but the specific role of the DA-TT is unclear at this stage.

Resources needed to better support the TT effort:

  • Dedicated funding for a scientist to reinvigorate efforts to inter-compare aspects of operational data assimilation systems.

DA-TT online technical seminar series


The aim of these online seminars is to have an informal, in-depth discussion about topics related to the activities of the DA-TT and its members.

They can be used to share preliminary results from ongoing projects and solicit feedback from the group, to discuss a specific technical or scientific challenge, to propose collaborative work for the DA-TT, or other technical/scientific topics.

The seminars are planned for one hour with a presentation followed by questions and discussion.

They will take place on the last Monday of every other month, time tbc.


Date  Seminar  Presenter Topic
1 Dec 2022 Technical seminar (6) Marcin Chrust (ECMWF) Overview of Ocean DA developments at ECMWF
5 Sep 2022 Technical seminar (5) Andrea Storto (CNR) The use of neural networks for coupled ocean-acoustic DA
13 June 2022 Technical seminar (4) Jean-Michel Lellouche (Mercator Ocean international) Evolution of the Mercator global system at 1/12°
with a focus on data assimilation updates
14 Mar 2022 Technical seminar (3) Anthony Weaver (CERFACS) A scale-dependent hybrid background error covariance model for ocean DA
29 Nov 2021 Technical seminar (2) Matt Martin (Met Office) Developing the assimilation of satellite total surface current velocities
27 Sep 2021 Technical seminar (1) Andy Moore (UCSC) Properties of analysis and forecast errors derived from the adjoint of a 4D-Var system