Data Assimilation

Group Leader: 
Laurent Bertino


About us

The very best way to make a forecast out of a numerical model and a set of observations.

Research Objectives

  • International leadership in data assimilation, from theory to state-of-the-art applications within ocean and climate.  Presently at the forefront of applications of the Ensemble Kalman Filter (EnKF)

  • Contribute to operational oceanography (TOPAZforecast and reanalysis) and climate sciences (NorCPM: Seasonal to decadal predictions) with forecasts and reanalysis of the highest standard for the Arctic Ocean, sea ice, ecosystem and the coupled climate system.

  • Contribute to the improvement of modelling and observation techniques, by testing hypotheses on their respective uncertainties.

Target & priorities

  • Provide validated reanalyses and forecasts for the operational oceanography and climate community with a focus on the Arctic and the Nordic Seas. E.g., a 30-years Arctic ice-ocean-ecosystem reanalysis and a global climate reanalysis (1850-present), both including residual uncertainty estimates.

  • Provide a data assimilation framework able to take up new models and observations at the frontiers of technology. E.g., assimilation in the Lagrangian neXtSIM model, coupled data assimilation in NorCPM, observations with unconventional error characteristics such as satellite-borne sea ice thickness.

  • Favour the emergence of a new ocean modeling group at NERSC able to take up the latest ocean, sea ice and ecosystem model research into our flagship integrated systems. E.g., integration of neXtSIM and ECOSMO into TOPAZ.

  • Extend the theory of data assimilation for non-linear chaotic systems (assimilation in the unstable subspace, improved stochastic models). E.g., proposing new algorithms improving the performance of the Ensemble Kalman Filter.

  • Pursue innovative applications of data assimilation with high societal impacts.

Open Source softwares:

Associated group members (in other groups at NERSC):

  • François Counillon
  • Yiguo Wang
  • Jiping Xie
  • Tsuyoshi Wakamatsu
  • Tarkeshwar Singh

The larger Data Assimilation community in Bergen, Norway:


Name Area of Expertise
Antoine Bernigaud data assimilation
Geir Evensen
Julien Brajard
computer science
data assimilation
remote sensing
Laurent Bertino
data assimilation
sea ice
Léo Edel data assimilation
Sukun Cheng data assimilation
Yue Ying data assimilation


Your mission is to move a fractal, where do you start?

23.05.2023 - 11:30 Henrike Wilborn
Yue Ying and his colleagues have proven that their new data assimilation method is able to reliably correct the position of vortices – swirls in water. They...

Keeping an advanced sea-ice forecast on track with advanced data assimilation

08.05.2023 - 13:00 Henrike Wilborn
A new study shows that including satellite-based data for sea ice concentration and thickness through data assimilation can make our sea-ice forecasts with...

A summary of improvements to CMEMS' Arctic Monitoring Forecasting Center

15.11.2021 - 12:30 Henrike Wilborn
Outputs by the Arctic Monitoring Forecasting Center are being used for Norwegian emergency response tools, among many other societally relevant applications....

Successful third Crash Course on Data Assimilation

21.06.2021 - 10:45 Henrike Wilborn
In the beginning of June, NERSC researchers ran their third Data Assimilation summer school, together with NORCE colleagues, and this time digitally. Over 70...

Publication: Data assimilation in the geosciences - An overview of methods, issues, and perspectives

29.10.2018 - 10:40 Asle Wingsternes
You have data, you have a simulation model, then you should probably look into data assimilation.  The term "Data Assimilation" depicts all the methods...

Summer School: “Crash Course on Data Assimilation - Theoretical foundations and advanced applications with focus on ensemble methods”

06.12.2016 - 10:27 Lasse Pettersson
The Nordic Centre of Excellence Ensemble-based data assimilation for environmental monitoring and prediction - EmblA coordinated by the Nansen Center organises...