• Application of a hybrid EnKF-OI to ocean forecasting 

      Counillon, François; Sakov, Pavel; Bertino, Laurent (Journal article, 2009-10-01)
      Data assimilation methods often use an ensemble to represent the background error covariance. Two approaches are commonly used; a simple one with a static ensemble, or a more advanced one with a dynamic ensemble. The latter ...
    • Arctic Sea level Budget Assessment During the GRACE/Argo Time Period 

      Raj, Roshin Pappukutty; Andersen, Ole Baltazar; Johannessen, Johnny Andre; Benjamin, Gutknech; Chatterjee, Sourav; Rose, Stine; Bonaduce, Antonio; Horwath, Martin; Ranndal, Heidi; Richter, Kristin; Palanisamy, Hindumathi; Ludwigsen, Carsten; Bertino, Laurent; Nilsen, Jan Even Øie; Knudsen, Per; Hogg, Anna E.; Cazenave, Anny; Benveniste, Jérôme (Journal article; Peer reviewed, 2020)
      Sea level change is an important indicator of climate change. Our study focuses on the sea level budget assessment of the Arctic Ocean using: (1) the newly reprocessed satellite altimeter data with major changes in the ...
    • Combined influence of oceanic and atmospheric circulations on Greenland sea ice concentration 

      Chatterjee, Sourav; Raj, Roshin Pappukutty; Bertino, Laurent; Mernild, Jacob Sebastian Haugaard; Subeesh, Meethale P.; Murukesh, Nuncio; Ravichandran, Muthalagu (Journal article; Peer reviewed, 2021)
      The amount and spatial extent of Greenland Sea (GS) ice are primarily controlled by the sea ice export across the Fram Strait (FS) and by local seasonal sea ice formation, melting, and sea ice dynamics. In this study, using ...
    • A comparison of Langmuir turbulence parameterizations and key wave effects in a numerical model of the North Atlantic and Arctic Oceans 

      Ali, Alfatih; Christensen, Kai Håkon; Breivik, Øyvind; Bertino, Laurent; Malila, Mika Petteri; Raj, Roshin Pappukutty; Chassignet, Eric P.; Bakhoday Paskyabi, Mostafa (Peer reviewed; Journal article, 2019)
      Five different parameterizations of Langmuir turbulence (LT) effect are investigated in a realistic model of the North Atlantic and Arctic using realistic wave forcing from a global wave hindcast. The parameterizations ...
    • Data assimilation as a learning tool to infer ordinary differential equation representations of dynamical models 

      Bocquet, Marc; Brajard, Julien; Carrassi, Alberto; Bertino, Laurent (Peer reviewed; Journal article, 2019)
      Recent progress in machine learning has shown how to forecast and, to some extent, learn the dynamics of a model from its output, resorting in particular to neural networks and deep learning techniques. We will show how ...
    • Evaluating two numerical advection schemes in HYCOM for eddy-resolving modelling of the Agulhas Current 

      Backeberg, Bjørn C.; Bertino, Laurent; Johannessen, Johnny A. (Ocean Science, Journal article, 2009-06-02)
      A 4th order advection scheme is applied in a nested eddy-resolving Hybrid Coordinate Ocean Model (HYCOM) of the greater Agulhas Current system for the purpose of testing advanced numerics as a means for improving the model ...
    • An Evaluation of the EnKF vs. EnOI and the Assimilation of SMAP, SMOS and ESA CCI Soil Moisture Data over the Contiguous US 

      Blyverket, Jostein; Hamer, Paul David; Bertino, Laurent; Albergel, Clement; Fairbairn, David; Lahoz, William A. (Peer reviewed; Journal article, 2019-02-26)
      A number of studies have shown that assimilation of satellite derived soil moisture using the ensemble Kalman Filter (EnKF) can improve soil moisture estimates, particularly for the surface zone. However, the EnKF is ...
    • The greater Agulhas Current system: an integrated study of its mesoscale variability 

      Backeberg, Bjørn C.; Johannessen, Johnny A.; Bertino, Laurent; Reason, Chris J.C. (Journal of Operational Oceanography, Journal article, 2008-02)
      For the purpose of developing an operational oceanography system for the greater Agulhas Current regime, a high resolution Hybrid Coordinate Ocean Model (HYCOM) has been set in a nested configuration. The intense and complex ...
    • The impact of ensemble filter definition on the assimilation of temperature profiles in the tropical Pacific 

      Leeuwenburgh, O.; Evensen, Geir; Bertino, Laurent (Journal article; Peer reviewed, 2005-10)
      The traditional analysis scheme in the Ensemble Kalman Filter (EnKF) uses a stochastic perturbation or randomization of the measurements which ensures a correct variance in the updated ensemble. An alternative so called ...
    • Observing system evaluation based on ocean data assimilation and prediction systems: On-going challenges and future vision for designing/supporting ocean observational networks 

      Fujii, Yosuke; Rémy, Elisabeth; Hao, Zuo; Oke, Peter; Halliwell, George; Gasparin, Florent; Benkiran, Mounir; Loose, Nora; Cummings, James; Xie, Jiping; Xue, Yan; Masuda, Shuhei; Smith, Gregory C.; Balmaseda, Magdalena; Germineaud, Cyril; Lea, Daniel J.; Larnicol, Gilles; Bertino, Laurent; Bonaduce, Antonio; Brasseur, Pierre; Donion, Craig; Heimbach, Patrick; Kim, YoungHo; Kourafalou, Villy; Le Traon, Pierre-Yves; Martin, Matthew; Paturi, Shastri; Tranchant, Benoit; Usui, Norihisa (Peer reviewed; Journal article, 2019-07-29)
      This paper summarizes recent efforts on Observing System Evaluation (OS-Eval) by the Ocean Data Assimilation and Prediction (ODAP) communities such as GODAE OceanView and CLIVAR-GSOP. It provides some examples of existing ...
    • Ocean data assimilation systems for GODAE 

      Cummings, James; Bertino, Laurent; Brasseur, Pierre; Fukumori, Ichiro; Kamachi, Masafumi; Martin, Matthew J.; Mogensen, Kristian; Oke, Peter; Testut, Charles Emmanuel; Verron, Jaques; Weaver, Anthony (Oceanography, GODAE Special issue feature, Journal article, 2009-09)
      Ocean data assimilation has matured to the point that observations are now routinely combined with model forecasts to produce a variety of ocean products. Approaches to ocean data assimilation vary widely both in terms of ...
    • The relationship between the eddy-driven jet stream and northern European sea level variability 

      Mangini, Fabio; Chafik, Léon; Madonna, Erica; Li, Camille; Bertino, Laurent; Nilsen, Jan Even Øie (Journal article; Peer reviewed, 2021)
      Wintertime sea level variability over the northern European continental shelf is largely wind-driven. Using daily gridded sea level anomaly from altimetry, we examine both the spatial and the temporal relationship between ...
    • Seasonal-to-decadal predictions with the ensemble kalman filter and the Norwegian earth System Model: A twin experiment 

      Counillon, Francois; Bethke, Ingo; Keenlyside, Noel; Bentsen, Mats; Bertino, Laurent; Zheng, Fei (Peer reviewed; Journal article, 2014-03-10)
      Here, we firstly demonstrate the potential of an advanced flow dependent data assimilation method for performing seasonal-to-decadal prediction and secondly, reassess the use of sea surface temperature (SST) for initialisation ...
    • Validation and intercomparison studies within GODAE 

      Hernandez, F.; Bertino, Laurent; Brassington, Gary; Chassignet, E.; Cummings, James; Davidson, Fraser; Drévillon, M.; Garric, Gilles; Kamachi, Masafumi; Lellouche, J.-M.; Mahdon, R.; Martin, Matthew J.; Ratsimandresy, A.; Regnier, C. (Journal article, 2009-09)
      During the Global Ocean Data Assimilation Experiment (GODAE), seven international operational centers participated in a dedicated modeling system intercomparison exercise from February to April 2008. The objectives were: ...