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Julien Brajard

48
Documents

Presentation

My work is in the field of remote sensing, inverse modelling, machine learning and data assimilation. The objective is to propose new methodologies in order to extract knowledge from data and physical systems, more specifically in oceanography. Those methodologies were apply to estimate and forecast key variables and their associated uncertainty in the ocean such as phytoplankton and surface currents. The methodologies developed were using remote sensing data (satellite sensors). Key words : Machine learning, statistical methods, remotesensing, oceanography, computer science

Publications

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Machine Learning-Based Improvement of Aerosol Optical Depth from CHIMERE Simulations Using MODIS Satellite Observations

Farouk Lemmouchi , Juan Cuesta , Mathieu Lachatre , Julien Brajard , Adriana Coman
Remote Sensing, 2023, 15 (1510), ⟨10.3390/rs15061510⟩
Journal articles hal-04274400v1
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Adaptation of a Neuro-Variational Algorithm from SeaWiFS to MODIS-Aqua Sensor for the Determination of Atmospheric and Oceanic Variables

Khassoum Correa , Eric Machu , Julien Brajard , Daouda Diouf , Saïdou Moustapha Sall
Remote Sensing, 2023, 15 (14), pp.3613. ⟨10.3390/rs15143613⟩
Journal articles hal-04262724v1
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Surface circulation properties in the eastern Mediterranean emphasized using machine learning methods

Georges Baaklini , Roy El Hourany , Milad Fakhri , Julien Brajard , Leila Issa
Ocean Science, 2022, 18 (5), pp.1491-1505. ⟨10.5194/os-18-1491-2022⟩
Journal articles hal-03868344v1
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54 years of microboring community history explored by machine learning in a massive coral from Mayotte (Indian Ocean)

Diego Alaguarda , Julien Brajard , G. Coulibaly , M. Canesi , Éric Douville
Frontiers in Marine Science, 2022, 9, ⟨10.3389/fmars.2022.899398⟩
Journal articles hal-03938202v1
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Blending drifters and altimetric data to estimate surface currents: Application in the Levantine Mediterranean and objective validation with different data types

Georges Baaklini , Leila Issa , Milad Fakhri , Julien Brajard , Gina Fifani
Ocean Modelling, 2021, 166, pp.101850. ⟨10.1016/j.ocemod.2021.101850⟩
Journal articles hal-03329128v1
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Bridging observations, theory and numerical simulation of the ocean using machine learning

Maike Sonnewald , Redouane Lguensat , Daniel C. Jones , Peter D. Dueben , Julien Brajard
Environmental Research Letters, 2021, 16 (7), pp.073008. ⟨10.1088/1748-9326/ac0eb0⟩
Journal articles hal-03311328v1
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Fusion of Rain Radar Images and Wind Forecasts in a Deep Learning Model Applied to Rain Nowcasting

Vincent Bouget , Dominique Béréziat , Julien Brajard , Anastase Alexandre Charantonis , Arthur Filoche
Remote Sensing, 2021, 13 (2), pp.246. ⟨10.3390/rs13020246⟩
Journal articles hal-03112093v1
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Partial differential equations for oceanic artificial intelligence

Jules Guillot , Guillaume Koenig , Kadi Minbashian , Emmanuel Frénod , Héléne Flourent
ESAIM: Proceedings and Surveys, 2021, 70, pp.137-146. ⟨10.1051/proc/202107009⟩
Journal articles hal-03265258v1
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Combining data assimilation and machine learning to emulate a dynamical model from sparse and noisy observations: A case study with the Lorenz 96 model

Julien Brajard , Alberto Carrassi , Marc Bocquet , Laurent Bertino
Journal of computational science, 2020, 44, pp.101171. ⟨10.1016/j.jocs.2020.101171⟩
Journal articles hal-03147335v1
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Estimation of phytoplankton pigments from ocean-color satellite observations in the Senegalo–Mauritanian region by using an advanced neural classifier

Khalil Yala , N'Dèye Niang , Julien Brajard , Carlos Mejia , Mory Ouattara
Ocean Science, 2020, 16 (2), pp.513-533. ⟨10.5194/os-16-513-2020⟩
Journal articles hal-02904148v1
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Data assimilation as a learning tool to infer ordinary differential equation representations of dynamical models

Marc Bocquet , Julien Brajard , Alberto Carrassi , Laurent Bertino
Nonlinear Processes in Geophysics, 2019, 26 (3), pp.143-162. ⟨10.5194/npg-26-143-2019⟩
Journal articles hal-02517929v1
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First Evidence of Anoxia and Nitrogen Loss in the Southern Canary Upwelling System

Éric Machu , Xavier Capet , Philippe Estrade , Siny Ndoye , Julien Brajard
Geophysical Research Letters, 2019, 46 (5), pp.2619-2627. ⟨10.1029/2018GL079622⟩
Journal articles hal-02067752v1
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Variational assimilation of land surface temperature within the ORCHIDEE Land Surface Model Version 1.2.6

Hector-Simon Benavidès Pinjosovsky , Sylvie Thiria , Catherine Ottlé , Julien Brajard , Fouad Badran
Geoscientific Model Development, 2017, 10 (1), pp.85-104. ⟨10.5194/gmd-10-85-2017⟩
Journal articles hal-01492602v1
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Silicon cycle in Indian estuaries and its control by biogeochemical and anthropogenic processes

K.R. Mangalaa , Damien Cardinal , Julien Brajard , D.B. Rao , N.S. Sarma
Continental Shelf Research, 2017, 148, pp.64-88. ⟨10.1016/j.csr.2017.08.011⟩
Journal articles hal-01651900v1
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Modelling surface currents in the Eastern Levantine Mediterranean using surface drifters and satellite altimetry

Leila Issa , Julien Brajard , Milad Fakhri , Daniel Hayes , Laurent Mortier
Ocean Modelling, 2016, 104, pp.1-14. ⟨10.1016/j.ocemod.2016.05.006⟩
Journal articles hal-01357669v1
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High Performance Numerical Validation using Stochastic Arithmetic

Pacôme Eberhart , Julien Brajard , Pierre Fortin , Fabienne Jézéquel
Reliable Computing, 2015, 21, pp.35-52
Journal articles hal-01254446v1
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Inferring the seasonal evolution of phytoplankton groups in the Senegalo-Mauritanian upwelling region from satellite ocean-color spectral measurements

Ousmane Farikou , Salam Sawadogo , Awa Niang , Daouda Diouf , Julien Brajard
Journal of Geophysical Research. Oceans, 2015, 120 (9), pp.6581--6601. ⟨10.1002/2015JC010738⟩
Journal articles hal-01507522v1

Multivariate analysis of the Senegalo-Mauritanien area by merging satellite remote sensing ocean color and SST observations

Ousmane Farikou , Salam Sawadogo , Niang Awa , Julien Brajard , Carlos Mejia
Journal of Research in Environmental and Earth Sciences, 2013, ⟨10.19026/RJEES.5.5733⟩
Journal articles hal-02079429v1

Retrieving aerosol characteristics and sea-surface chlorophyll from satellite ocean color multi-spectral sensors using a neural-variational method

Daouda Diouf , Awa Niang , Julien Brajard , Michel Crépon , Sylvie Thiria
Remote Sensing of Environment, 2013, 130, pp.74 - 86. ⟨10.1016/j.rse.2012.11.002⟩
Journal articles hal-01495282v1

Atmospheric correction of MERIS data for case-2 waters using a neuro-variational inversion

Julien Brajard , Richard Santer , Michel Crépon , Sylvie Thiria
Remote Sensing of Environment, 2012, 126, pp.51 - 61. ⟨10.1016/j.rse.2012.07.004⟩
Journal articles hal-01495015v1
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Atmospheric correction of SeaWiFS ocean color imagery in the presence of absorbing aerosols off the Indian coast using a neuro-variational method

Julien Brajard , Cyril Moulin , Sylvie Thiria
Geophysical Research Letters, 2008, 35, pp.20604. ⟨10.1029/2008GL035179⟩
Journal articles hal-00752788v1

Inversion of satellite ocean colour imagery and geoacoustic characterization of seabed properties: Variational data inversion using a semi-automatic adjoint approach

Fouad Badran , Mohamed Berrada , Julien Brajard , Michel Crépon , Charles Sorror
Journal of Marine Systems, 2008, 69 (1-2), pp.126--136. ⟨10.1016/j.jmarsys.2007.02.018⟩
Journal articles hal-01507523v1

Estimating aerosol parameters above the ocean from MERIS observations using topological maps

Julien Brajard , Awa Niang , Salam Sawadogo , Frank Fell , Richard Santer
International Journal of Remote Sensing, 2007, 28 (3-4), pp.781--795. ⟨10.1080/01431160600821101⟩
Journal articles hal-01507524v1

Use of a neuro-variational inversion for retrieving oceanic and atmospheric constituents from satellite ocean colour sensor: Application to absorbing aerosols

Julien Brajard , Cédric Jamet , Cyril Moulin , Sylvie Thiria
Neural Networks, 2006, 19, pp.178-185. ⟨10.1016/j.neunet.2006.01.015⟩
Journal articles hal-00122477v1

Validation of a neuro-variational inversion of ocean colour images

Julien Brajard , Cédric Jamet , Cyril Moulin , Sylvie Thiria
Advances in Space Research, 2006, 38 (10), pp.2169-2175. ⟨10.1016/j.asr.2006.03.039⟩
Journal articles hal-00750296v1
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Learning 4DVAR inversion directly from observations

Arthur Filoche , Julien Brajard , Anastase Charantonis , Dominique Béréziat
Workshop on Machine Learning and Data Assimilation for Dynamical Systems (MLDADS), International Conference on Computational Science (ICCS), Jul 2023, Prague, Czech Republic
Conference papers hal-03863390v2
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Variational assimilation of Geophysical images leveraging deep learning tools

Arthur Filoche , Dominique Béréziat , Julien Brajard , Anastase Alexandre Charantonis
ORASIS 2021, Centre National de la Recherche Scientifique [CNRS], Sep 2021, Saint Ferréol, France
Conference papers hal-03339674v1

Mesoscale Activity in the Eastern Mediterranean: Blending Altimetry with in situ observations

Georges Baaklini , Leila Issa , Julien Brajard , Milad Fakhri , Milena Menna
EGU General assembly 2020, May 2020, virtual, Zimbabwe. ⟨10.5194/egusphere-egu2020-20407⟩
Conference papers hal-03082863v1
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Completing physics-based models by learning hidden dynamics through data assimilation

Arthur Filoche , Julien Brajard , Anastase Alexandre Charantonis , Dominique Béréziat
NeurIPS 2020, workshop AI4Earth, Dec 2020, Vancouver (virtual), Canada
Conference papers hal-03004938v1

Can a neural network learn a numerical model ?

Julien Brajard , Anastase Alexandre Charantonis , Jérôme Sirven
EGU General Assembly, Apr 2018, Vienne, Austria
Conference papers hal-02067473v1

Improving CADNA Performance on GPUs

Pacôme Eberhart , Baptiste Landreau , Julien Brajard , Pierre Fortin , Fabienne Jézéquel
2018 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW), May 2018, Vancouver, Canada. pp.1016-1025, ⟨10.1109/IPDPSW.2018.00156⟩
Conference papers hal-01858537v1

Predicting Ocean Dynamics through Machine Learning: Application on Sea-Surface Suspended Particulate Mater

Julien Brajard , Anastase Alexandre Charantonis , Frédéric Jourdin
American Meteorological Society Annual Meeting 2017, American Meteorological Society, Jan 2017, Seattle, United States
Conference papers hal-01477182v1

Ensemble variational data assimilation with a shallow-water model: preliminary results

Julien Brajard , Jérôme Sirven , Olivier Talagrand
EGU General Assembly, Apr 2016, Vienne, Austria. pp.14836
Conference papers hal-01507519v1

Determination of phytoplankton groups from space: application to senegalo-mauritanean upwelling

Yala Khalil , Julien Brajard , Michel Crépon , Éric Machu , Ndèye Niang
EGU General Assembly, 2016, Vienne, Austria. pp.15098
Conference papers hal-01507521v1
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Estimation of Round-off Errors in OpenMP Codes

Pacôme Eberhart , Julien Brajard , Pierre Fortin , Fabienne Jézéquel
IWOMP 2016 - 12th International Workshop on OpenMP, Riken AICS, Oct 2016, Nara, Japan. pp.3-16, ⟨10.1007/978-3-319-45550-1_1⟩
Conference papers hal-01380131v1
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Determination of phytoplankton groups from ocean color spectral measurements in the Senegalo-Mauritanian upwelling

Ymane Taoufiq , Ousmane Farikou , Séverine Alvain , Julien Brajard , Michel Crépon
Ocean Optics, The Oceanography Society (TOS), Oct 2014, Portland, Maine, United States
Conference papers hal-01191676v1

Towards high performance stochastic arithmetic

Pacôme Eberhart , Julien Brajard , Pierre Fortin , Fabienne Jézéquel
16th international symposium on Scientific Computing, Computer Arithmetic and Validated Numerics (SCAN 2014), Sep 2014, Würzburg, Germany. pp.47-48
Conference papers hal-01217244v1

Numerical Validation of Data Assimilation Codes Generated by the YAO Software

Julien Brajard , Pei Li , Fabienne Jézéquel , Hector-Simon Benavidès Pinjosovsky , Sylvie Thiria
SIAM Annual Meeting, Jul 2013, San Diego, California, United States
Conference papers hal-01216453v1

Neuro-Variational Inversion Applied to Ocean Color Remote Sensing

Julien Brajard , Daouda Diouf , Hector-Simon Benavidès Pinjosovsky , Michel Crépon , Richard Santer
American Meteorological Society Annual Meeting, 2012, La Nouvelle Orléans, United States
Conference papers hal-00750316v1

Variational data assimilation in NEMO using YAO

Mohamed Berrada , Julien Brajard , Charles Deltel , Michel Crépon , Fouad Badran
Congrès European Geophysical Union, 2011, Vienne, Austria
Conference papers hal-00750253v1

Inverse method for the retrieval of ocean vertical profiles using self-organizing maps and hidden Markov models - Application on Ocean Colour Satellite Image Inversion

Anastase Alexandre Charantonis , Julien Brajard , Cyril Moulin , Fouad Badran , Sylvie Thiria
NCTA 2011 : NCTA- International Conference on Neural Computation Theory and Applications, 2011, Paris, France
Conference papers hal-00750300v1

Retrieving aerosol characteristics from satellite ocean color multi-spectral sensors using a neural-variational method

Daouda Diouf , Sylvie Thiria , Awa Niang , Julien Brajard , Michel Crépon
NCTA 2011 : NCTA- International Conference on Neural Computation Theory and Applications, 2011, Paris, France
Conference papers hal-00750307v1

Inversion of sea surface data to retrieve the vertical distribution of phytoplankton using a statistical methodology

Anastase Alexandre Charantonis , Sylvie Thiria , Cyril Moulin , Julien Brajard
Congrès European Geophysical Union, 2011, Vienne, Austria
Conference papers hal-00750248v1

Atmospheric correction and chlorophyll-a restitution in presence of Saharan dusts

Daouda Diouf , Julien Brajard , Awa Niang , Salam Sawadogo , Michel Crépon
Congrès European Geophysical Union, 2011, Vienne, Austria
Conference papers hal-00750241v1
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Modeling Surface Currents in the Eastern Levantine Mediterranean

Leila Issa , Julien Brajard , Milad Fakhri , Laurent Mortier , Pierre-Marie Poulain
EGU General Assembly Conference, Apr 2015, Vienna, Austria. 17, pp.8888
Conference poster hal-01191755v1