Sebastien Massart

Senior Scientist
Research Department, Earth System Assimilation Section, Data Assimilation Methodology Group

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Sebastien joined ECMWF in March 2012 as a scientist on the assimilation of the greenhouse gases for the MACC (Monitoring Atmospheric Composition and Climate) projects. He then continued this activity as part of the Copernicus Atmosphere Monitoring Service (CAMS).

Sebastien moved to the data assimilation methodology team in December 2016. His main focus is the sustenance of ECMWF assimilation system. He also participate to the development of the OOPS project and helps on its scientific validation.

Professional interests: 
  • Data assimilation methodology
  • Ensemble methods
  • Atmospheric chemistry
Career background: 
  • Education:

    • Master Degree in Engineering, ENSEEIHT, Toulouse 1999

    • PhD on Earth Science, Environment and data assimilation, INP Toulouse, France, 2003

  • Job History

    • December 2002 to March 2012: CERFACS
    • March 2012 to December 2016: ECMWF CAMS
    • From December 2016: ECMWF DAM
  • Summary of experience:

    I have been working with data assimilation methods for more than sixteen years. My experience includes the implementation and use of data assimilation for various models (mostly geosciences models) and with various methods.

    Between 2003 and 2012, I have been developing in Fortran the Valentina chemical data assimilation system. Valentina is a flexible and modular variational assimilation suite allowing global and regional chemical transport models to assimilate data with a 3D-Var, a 3D-FGAT or a 4D-Var method (see publications list). I further develop this activity within the framework of the series of the Monitoring Atmospheric Composition and Climate (MACC) European projects. These projects helped me to build a team of three people around Valentina, team I managed during several years.

    Together we coupled Valentina with the global and the regional versions of the Meteo-France/CNRM Mocage chemistry transport model. The regional version of this coupled system is currently used operationally in the Copernicus Atmosphere Monitoring Service (CAMS) to produce regional air quality analyses.

    Although I have mainly focused on variational assimilation methods for the development of Valentina, I am also very familiar with Kalman filter methods and ensemble methods. Part of my studies are based on hybrid methods and aimed to diagnose and formulate the covariance matrix of the background error, both for a global system assimilating satellite data (Pannekoucke and Massart, 2008, Massart et al., 2011) and a regional system assimilating in situ data (Jaumouille et al., 2011). My experience also covers some more methodological aspects of data assimilation like highlighting some issues of the 3D-FGAT method for transport models (Massart et al., 2010).

    Apart from atmospheric chemistry, my work concerned several other components of the Earth system. I used to work with Nemo-Var, the assimilation system which is used for the ocean reanalysis ORAS5. I also participated to the development of an assimilation system for the French National Hydrometeorological and Flood Forecasting Center (SCHAPI) to further improve their operational flood forecast over France.

    I joined ECMWF in 2012 to further develop the assimilation of the greenhouse gas satellite data as part of the MACC projects and then CAMS. In parallel, I explored and expanded hybrid assimilation methods similar to the ones used in the Research Department. I first adapted ECMWF Ensemble of Data Assimilations (EDA) to the CAMS greenhouse gases in collaboration with the Data Assimilation Methodology Team of the Earth System Assimilation Section (Massart and Bonavita, 2016). I also explored the use of ECMWF Ensemble Kalman Filter (EnKF) for the greenhouse gases in collaboration with the Numerical Methods team of the Earth System Modelling Section.
    Since end of 2016 I moved to the data assimilation methodology team to work mainly on hydrib 4D-Var.




Peer-reviewed publications as a first author

  1.  Massart, S., A. Agustí-Panareda, J. Heymann, M. Buchwitz, F. Chevallier, M. Reuter, M. Hilker, J. P. Burrows, N. M. Deutscher, D. G. Feist, F. Hase, R. Sussmann, F. Desmet, M. K. Dubey, D. W. T. Griffith, R. Kivi, C. Petri, M. Schneider, and V. A. Velazco (2016): Ability of the 4D-Var analysis of the GOSAT BESD XCO 2 retrievals to characterize atmospheric CO 2 at large and synoptic scales, Atmos. Chem. Phys., 16, 1653-1671.
  2. Massart, S. , A. AgustÍ-Panareda, I. Aben, A. Butz, F. Chevallier, C. Crevosier, R. Engelen, C. Frankenberg and O. Hasekamp (2014): Assimilation of atmospheric methane products into the MACC-II system: from SCIAMACHY to TANSO and IASI, Atmos. Chem. Phys., 12, 6139—6158.
  3. Massart, S., A. Piacentini and O. Pannekoucke (2012): Importance of using an ensemble estimated background error covariances for the quality of atmospheric ozone analyses, Q. J. R. Meteorol., 138, 889—905.
  4. Massart, S., B. Pajot, A. Piacentini and O. Pannekoucke (2010): On the merits of using a 3D-FGAT assimilation scheme with an outer loop for atmospheric situations governed by transport, Mon. Wea. Rev., doi: 10.1175/2010MWR3237.1.
  5. Massart, S., C. Clerbaux, D. Cariolle, A. Piacentini, S. Turquety and J. Hadji-Lazaro (2009): First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system, Atmos. Chem. and Phys., 9, 5073—5091.
  6. Massart S., S. Buis, P. Erhard and G. Gacon (2007): Use of 3D-VAR and Kalman filter approaches for neutronic state and parameter estimation in nuclear reactors, Nucl. Sci. Eng., 155, 409—424.
  7. Massart, S., A. Piacentini, D. Cariolle, L. El Amraoui and N. Semane (2007): Assessment of the quality of the ozone measurements from the Odin/SMR instrument using data , Can. J. Phys, 85, 1209—1223.
  8. Massart, S., D. Cariolle, and V.-H. Peuch (2005): Towards an improvement of the atmospheric ozone distribution and variability by assimilation of satellite data, C.R. Geoscience, 337 1305—1310.


Other peer-reviewed publications (by alphabetical order)

  1. Agustí-Panareda A., S. Massart, F. Chevallier, G. Balsamo, S. Boussetta, E. Dutra, and A. Beljaars (2016): A biogenic CO 2 flux adjustment scheme for the mitigation of large-scale biases in global atmospheric CO 2 analyses and forecasts, Atmos. Chem. Phys., 16, 10399—10418.
  2. AgustÍ-Panareda, A., S. Massart, F. Chevallier, S. Boussetta, G. Balsamo, A. Beljaars, P. Ciais, N M. Deutscher, R. Engelen, L. Jones, R. Kivi, J. –D. Paris, V. –H. Peuch, V. Sherlock, A. T. Vermeulen, P.O. Wennberg and D. Wunch (2014): Forecasting global atmospheric CO 2 , Atmos. Chem. Phys., 21, 11959—11983.
  3. Barret, B., P. Ricaud, C. Mari, J.-L. Attié, N. Bousserez, B. Josse, E. Le Flochmoën, N. J. Livesey, S. Massart, V.-H. Peuch, A. Piacentini, B. Sauvage, V. Thouret and J.-P. Cammas (2008): Transport pathways of CO in the African upper troposphere during the monsoon season: a study based upon the assimilation of spaceborne observations, Atmos. Chem. Phys., 8, 3231—3246.
  4. Bencherif, H., L. El Amraoui, N. Semane, S. Massart, D. Vidyaranya Charyulu, A. Hauchecorne and V.-H. Peuch, (2007): Examination of the 2002 major warming in the southern hemisphere using ground-based and Odin/SMR assimilated data: stratospheric ozone distributions and tropic/mid-latitude exchange, Can. J. Phys., 85, 1287—1300.
  5. Bouriquet, B., J.-P. Argaud, P. Erhard, S. Massart, A. Ponçot, S. Ricci and O. Thual (2011): Differential influence of instruments in nuclear core activity evaluation by data assimilation. Nucl. Instrum. Methods Phys. Res. A, 626-627, 97—104.
  6. Bouriquet, B., J.-P. Argaud, P. Erhard, S. Massart, A. Ponçot, S. Ricci and O. Thual (2011): Robustness of nuclear core activity reconstruction by data assimilation, Nucl. Instrum. Methods Phys. Res. A, 629, 282—287.
  7. Claeyman, M., J.-L. Attié, V.-H. Peuch, L. El Amraoui, W. A. Lahoz, B. Josse, M. Joly, J. Barré, P. Ricaud, S. Massart, A. Piacentini, T. von Clarmann, M. Höpfner, J. Orphal, J.-M. Flaud and D. P. Edwards (2011): A thermal infrared instrument onboard a geostationary platform for CO and O3 measurements in the lowermost troposphere: observing system simulation experiments. Atmos. Meas. Tech., 4, 1637—1661.
  8. Claeyman, M., J.-L. Attié, L. El Amraoui, D. Cariolle, V.-H. Peuch, H. Teyssèdre, B. Josse, P. Ricaud, S. Massart, A. Piacentini, J.-P. Cammas, N. L. Livesey, H. C. Pumphrey and D. P. Edwards (2010): A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation, Atmos. Chem. and Phys., 10, 6097—6115.
  9. El Amraoui, L., J.-L. Attié, N. Semane, M. Claeyman, V.-H. Peuch, J. Warner, P. Ricaud, J.-P. Cammas, A. Piacentini, B. Josse, D. Cariolle, S. Massart and H. Bencherif (2010): Midlatitude stratosphere-troposphere exchange as diagnosed by MLS O3 and MOPITT CO assimilated fields, Atmos. Chem. and Phys., 10, 2175—2194.
  10. El Amraoui, L., V.-H. Peuch, P. Richaud, S. Massart, J. Urban, N. Semane, H. Teyssedre, D. Cariolle and F. Karcher, (2008): Ozone loss in the 2002/03 Artic vortex deduced from the assimilation of O3 and N2O measurements: N2O as a dynamical tracer, Q. J. R. Meteorol. Soc., 134, 217-228.
  11. Emili, E., B. Barret, S. Massart, A. Piacentini, O. Pannekoucke and D. Cariolle (2014): Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model, Atmos. Chem. Phys., 14, 177—198.
  12. Geer, A. J., W. A. Lahoz, S. Bekki, N. Bormann, Q. Errera, H. J. Eskes, D. Fonteyn, D. R. Jackson, M. N. Juckes, S. Massart, V.-H. Peuch, S. Rharmili and A. Segers (2006): The ASSET intercomparison of ozone analyses: method and first results. Atmos. Chem. and Phys., 6, 5445—5474.
  13. Heymann, J. M. Reuter, M. Buchwitz, O. Schneising, H. Bovensmann, J. P. Burrows, S. Massart, J. W. Kaiser, D. Crisp (2017): CO2 emission of Indonesian fires in 2015 estimated from satellite-derived atmospheric CO 2 concentrations, Geophysical Research Letters, 44, 3, 1537—1544.
  14. Jaumouillé, E., S. Massart, A. Piacentini, D. Cariolle, and V.-H. Peuch (2012): Impact of a time-dependent background error covariance matrix on air quality analysis, Geosci. model dev., 5,1075—1090·
  15. Lahoz, W. A., A. J. Geer, S. Bekki, N. Bormann, S. Ceccherini, H. Elbern, Q. Errera, H. J. Eskes, D. Fonteyn, D. R. Jackson, B. Khattatov, S. Massart, V.-H. Peuch, S. Rharmili, M. Ridolfi, A. Segers, O. Talagrand, H. E. Thornton, A. F. Vik and T. von Clarmann (2007): The Assimilation of Envisat data (ASSET) project, Atmos. Chem. and Phys., 7, 1773—1796.
  16. Leutbecher, M., S.-J. Lock, P. Ollinaho, S. Lang, G. Balsamo, P. Bechtold, M. Bonavita, H. M. Christensen, M, Diamantakis, E. Dutra, S. English, M. Fisher, R. M. Forbes, J. Goddard,T. Haiden, R. J. Hogan, S. Juricke, H. Lawrence, D. MacLeod, L. Magnusson, S., Malardel, S. Massart, I. Sandu, P. K. Smolarkiewicz, A., Subramanian, F. Vitart, N. Wedi, and A. Weisheimer (2017): Stochastic representations of model uncertainties at ECMWF: state of the art and future vision. Q.J.R. Meteorol. Soc, 143: 2315–2339.
  17. Pajot, B., S. Massart, D. Cariolle, A. Piacentini, O. Pannekoucke, W. A. Lahoz, C. Clerbaux, P. F Coheur and D. Hurtmans (2011): High resolution assimilation of IASI ozone data with a global CTM, Atmos. Chem. and Phys. Discuss., 11, 29357—29406.
  18. Pannekoucke, O. and S. Massart (2008): Estimation of the local diffusion tensor and normalization for heterogeneous correlation modelling using a diffusion equation, Q. J. R. Meteorol. Soc., 134, 1425-1438.
  19. Ricaud, P., R. Zbinden, V. Catoire, V. Brocchi, F. Dulac, E. Hamonou, J. Canonici, L. El Amraoui, S. Massart, B. Piguet, U. Dayan, P. Nabat, J. Sciare, M. Ramonet, M. Delmotte, A. di Sarra, D. Sferlazzo, T. di Iorio, S. Piacentino, P. Cristofanelli, N. Mihalopoulos, G.  Kouvarakis, M. Pikridas, C. Savvides, R. Mamouri, A. Nisantzi, D. Hadjimitsis, J. Attié, H. Ferré, Y. Kangah, N. Jaidan, J. Guth, P. Jacquet, S. Chevrier, C. Robert, A. Bourdon, J. Bourdinot, J. Etienne, G. Krysztofiak, and P. Theron, 0 (2017): The GLAM airborne campaign across the Mediterranean Basin. Bull. Amer. Meteor. Soc.
  20. Rochoux, M. C., B. Cuenot, S. Ricci, A. Trouvé, B. Delmotte, S. Massart, R. Paoli and R. Paugam (2013): Data assimilation applied to combustion, Comptes Rendus Mecanique, 341, 266—276.
  21. Semane, N., V.-H. Peuch, S. Pradier, G. Desroziers, L. El Amraoui, P. Brousseau, S. Massart, B. Chapnik and A. Peuch (2009): On the extraction of wind information from the assimilation of ozone profiles in Météo-France 4D-Var operational NWP suite, Atmos. Chem. Phys., 9, 4855—4867.
  22. Semane, N., V.-H. Peuch, L. El Amraoui, H. Bencherif, S. Massart, D. Cariolle, J.-L. Attié and R. Abida (2007): An observed and analysed stratospheric ozone intrusion over the high Canadian Arctic UTLS region during the summer of 2003, Q. J. R. Meteorol. Soc., 113, 171—178.
  23. Thirel, G., E. Martin, J.-F. Mahfouf, S. Massart, S. Ricci and F. Habets (2010): A past discharges assimilation system for ensemble streamflow forecasts over France – Part 1: Description and validation of the assimilation system, Hydrol. Earth Syst. Sci., 14, 1623—1637.
  24. Thirel, G., E. Martin, J.-F. Mahfouf, S. Massart, S. Ricci, F. Regimbeau and F. Habets (2010): A past discharge assimilation system for ensemble streamflow forecasts over France – Part 2: Impact on the ensemble streamflow forecasts, Hydrol. Earth Syst. Sci., 14, 1639—1653.
  25. Verma, S., J. Marshall, M. Parrington, A. Agustí-Panareda, S. Massart, M. P. Chipperfield, C. Wilson, and C. Gerbig (2017): Extending methane profiles from aircraft into the stratosphere for satellite total column validation using the ECMWF C-IFS and TOMCAT/SLIMCAT 3-D model, Atmos. Chem. Phys., 17, 6663—6678.

Recent technical publications

  1.  AgustÍ-Panareda, A., S. Massart, S. Boussetta, G., Balsamo, A. Beljaars, F. Chevallier, R. Engelen V.-H. Peuch, and M. Razinger (2013): The new MACC-II CO 2 forecast, ECMWF Newsletter, 135, 8—13.
  2. A. Agusti-Panareda, S. Massart, Harjinder Sembhi (2015): Report on the quality of the CO2 analysis and forecast 4D fields, MACC-III deliverable D 42.4, 18 pages
  3. Cariolle, D. and S. Massart (2014): Linearized chemistry schemes: Formulation and code, MACC-II deliverable D 57.6, 19 pages.
  4. Cariolle, D. and S. Massart (2015): Documentation of L-IFS, Formulation and code, MACC-III deliverable D 24.5, 17 pages.
  5. Massart, S. (2014): Revised prior errors, MACC-II deliverable D 42.3, 16 pages.
  6. Massart, S., A. Agusti-Panareda and R. Engelen (2014): Quality of the analysed CH 4 4D fields from the MACC-II delayed-mode system, MACC-II deliverable D 42.5, 17 pages.
  7. Massart, S., A. Agusti-Panareda and R. Engelen (2014): Quality of the analysed CO 2 4D fields from the MACC-II delayed-mode system, MACC-II deliverable D 42.6, 16 pages.
  8. Massart, S., A. Agusti-Panareda and R. Engelen (2014): Data assimilation system ready for OCO-2, MACC-II deliverable D 44.1, 5 pages.
  9. Massart, S., A. Agusti-Panareda and R. Engelen (2014): Data assimilation system ready for Sentinel-5p, MACC-II deliverable D 44.2, 5 pages.
  10. Massart, S., A. Agusti-Panareda (2014): Report on the benefit of a weak constraint 4D-Var for GHG, MACC-II deliverable D 44.5, 17 pages.
  11. Massart, S. (2014): Data assimilation system ready for GHG-cci datasets, MACC-II deliverable D44.8, 6 pages.
  12. Massart, S. and A. Agusti-Panareda (2015): Monitoring of OCO-2: achievements and plans, MACC-III deliverable D 44.1, 7 pages.
  13. Massart, S., J. Flemming, D. Cariolle and L. Jones (2015): High resolution CO tracer forecasts, MACC-III deliverable D 22.4, 14 pages.
  14. Massart, S. and M. Bonavita (2016): Ensemble of Data Assimilations applied to the CAMS'greenhouse gases analysis, ECMWF Technical Memorandum, 780, 25 pages.
  15. Massart, S., A. Agusti-Panareda and J. Flemming (2017): Evidence of a stratospheric methane bias in the IFS against MIPAS data, ECMWF Technical Memorandum, 814, 21 pages.



thumbnail photo of Sebastien Massart