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24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Logo SAS Logo de l'Institut Agro Rennes-Angers

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FLECHARD Christophe


Scientist at INRAE / UMR SAS

Phone: (+33) 02 23 48 52 22 • Email :

Address: INRAE Centre Bretagne-Normandie, UMR SAS, 65 rue de St-Brieuc, CS 84215, 35042 Rennes Cedex, France

Expertise: land-atmosphere exchange, atmospheric pollution, greenhouse gas sources and sinks, nitrogen cycle, carbon cycle, soil-vegetation-atmosphere transfer (SVAT) modelling, ecosystem modelling

Keywords: turbulent fluxes, micrometeorology, dry deposition, emission, dispersion, reactive nitrogen, ammonia, secondary inorganic aerosols, nitrous oxide, carbon dioxide, carbon sequestration


I am currently principal investigator (PI) of the FR-Mej (Mejusseaume) flux tower site over intensively-managed grassland in NW France, as part of the European ICOS research infrastructure ( I am also:

Current research topics

My research focuses on atmospheric, vegetation and soil processes controlling emissions, surface interactions and dry deposition of atmospheric reactive nitrogen species (especially NH3), and the exchange and ecosystem-scale budgets of greenhouse gases (N2O, CO2, CH4), affected by land management and global environmental change. My aim is to further process understanding of land-atmosphere exchange relevant for nitrogen and carbon cycling in terrestrial ecosystems, including agro-ecosystems, through long-term in situ observations of concentrations, fluxes and pools. I have managed flux monitoring stations over peatland, forest, grassland and cropland, using various trace gas flux measurement techniques, including chamber methods, micrometeorological techniques, flux towers (aerodynamic flux-gradient, eddy covariance), as well as mobile (aircraft- and automobile-based) platforms for measuring turbulent fluxes and dispersion plumes.

My research activities on total atmospheric deposition also involve the monitoring of atmospheric pollutant concentrations using a range of optical, spectroscopic, wet chemistry methods, as well as low-cost passive diffusion samplers and denuder/filter systems, as part of local-scale (landscape) gradient studies and national and international observation networks.

I contribute to the development, testing and calibration of soil-vegetation-atmosphere transfer (SVAT) and inferential (dry deposition) models and parameterizations, with a focus on chemical interactions on vegetation surfaces and in the soil controlling the exchange of NH3 and other key reactive pollutants. I also invoke ecosystem modelling to investigate the interactions between the carbon and nitrogen cycles, in particular the impact of atmospheric nitrogen deposition on ecosystem carbon sequestration and net greenhouse gas budgets.

Current research projects

  • CCCfarming: EU project (Climate Care Cattle Farming Systems), 2020-2023, coord. Wageningen University and Research
  • EMIGRAZE: ADEME-CORTEA (FR) project (Feeding strategies associating grazed and conserved forages: strengths or constraints for nitrogen efficiency and gas emissions in dairy systems?), 2020-2023, coord. INRAE-UMR PEGASE
  • RECAPS: ADEME-PRIMEQUAL (FR) project (Interactions and Feedbacks between Climate Change and Air Pollution: Impact of Agricultural Practices aiming to Increase Soil Carbon Stocks at the French scale), 2020-2023, coord. INRAE-UMR ECOSYS
  • ALBEDO-prairies: CASDAR (FR) project, 2020-2022, coord. IDELE
  • DEPSAT: INSU SNO-Tourbières (FR) project (Nitrogen dry deposition to peatland), 2019-20, coord. C. Flechard

Participation in networks

  • ICOS (Integrated Carbon Observation System, EU research infrastructure). Measurement site principal investigator
  • SNO-Tourbières (French national observation network on peatlands). Member of steering committee
  • SOERE PRO (French observation, experimentation and research network on the environmental effects of organic residues)

Teaching experience

Annual Master’s degree course since 2014: “Greenhouse gas fluxes in agro-ecosystems: observations, processes, drivers, interactions with the carbon, nitrogen and water cycles”, Agrocampus Ouest, Rennes.

Consulting experience

Member of World Meteorological Organisation WMO’s Science Advisory Group on Total Atmospheric Deposition (SAG-TAD)


Eddy covariance CO2/H2O flux tower over peatland at the SNO-Tourbières Landemarais site (FR-LDM)

Automated closed chamber system for soil N2O flux measurements, SOERE PRO-EFELE site

Comparison of NH3 flux measurement systems over grazed grassland 


Flechard, C. R., Ibrom, A., Skiba, U. M., de Vries, W., van Oijen, M., Cameron, D. R., Dise, N. B., Korhonen, J. F. J., Buchmann, N., Legout, A., Simpson, D., Sanz, M. J., Aubinet, M., Loustau, D., Montagnani, L., Neirynck, J., Janssens, I. A., Pihlatie, M., Kiese, R., Siemens, J., Francez, A.-J., Augustin, J., Varlagin, A., Olejnik, J., Juszczak, R., Aurela, M., Berveiller, D., Chojnicki, B. H., Dämmgen, U., Delpierre, N., Djuricic, V., Drewer, J., Dufrêne, E., Eugster, W., Fauvel, Y., Fowler, D., Frumau, A., Granier, A., Gross, P., Hamon, Y., Helfter, C., Hensen, A., Horváth, L., Kitzler, B., Kruijt, B., Kutsch, W. L., Lobo-do-Vale, R., Lohila, A., Longdoz, B., Marek, M. V., Matteucci, G., Mitosinkova, M., Moreaux, V., Neftel, A., Ourcival, J.-M., Pilegaard, K., Pita, G., Sanz, F., Schjoerring, J. K., Sebastià, M.-T., Tang, Y. S., Uggerud, H., Urbaniak, M., van Dijk, N., Vesala, T., Vidic, S., Vincke, C., Weidinger, T., Zechmeister-Boltenstern, S., Butterbach-Bahl, K., Nemitz, E., and Sutton, M. A.: Carbon–nitrogen interactions in European forests and semi-natural vegetation – Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling, Biogeosciences, 17, 1583–1620,, 2020.

Flechard, C. R., van Oijen, M., Cameron, D. R., de Vries, W., Ibrom, A., Buchmann, N., Dise, N. B., Janssens, I. A., Neirynck, J., Montagnani, L., Varlagin, A., Loustau, D., Legout, A., Ziemblińska, K., Aubinet, M., Aurela, M., Chojnicki, B. H., Drewer, J., Eugster, W., Francez, A.-J., Juszczak, R., Kitzler, B., Kutsch, W. L., Lohila, A., Longdoz, B., Matteucci, G., Moreaux, V., Neftel, A., Olejnik, J., Sanz, M. J., Siemens, J., Vesala, T., Vincke, C., Nemitz, E., Zechmeister-Boltenstern, S., Butterbach-Bahl, K., Skiba, U. M., and Sutton, M. A.: Carbon–nitrogen interactions in European forests and semi-natural vegetation – Part 2: Untangling climatic, edaphic, management and nitrogen deposition effects on carbon sequestration potentials, Biogeosciences, 17, 1621–1654,, 2020.

Fowler, D., Steadman, C. E., Stevenson, D., Coyle, M., Rees, R. M., Skiba, U. M., Sutton, M. A., Cape, J. N., Dore, A. J., Vieno, M., Simpson, D., Zaehle, S., Stocker, B. D., Rinaldi, M., Facchini, M. C., Flechard, C., Nemitz, E., Twigg, M., Erisman, J. W., Butterbach-Bahl, K., Galloway, J. N. (2015). Effects of global change during the 21st century on the nitrogen cycle. Atmospheric Chemistry and Physics, 15 (24), 13849-13893,

[Van Damme, M., Clarisse, L., Dammers, E., Liu, X., Nowak, J. B., Clerbaux, C., Flechard , C. R., Galy-Lacaux, C., Xu, W., Neuman, J. A., Tang, Y. S., Sutton, M. A., Erisman, J. W., Coheur, P. F. (2015). Towards validation of ammonia (NH3) measurements from the IASI satellite. Atmospheric Measurement Techniques, 8 (3), 1575-1591,

Bell, M, C.R. Flechard, Y. Fauvel, C. Häni, J. Sintermann, M. Jocher, H. Menzi, A. Hensen, and A. Neftel (2017). Ammonia emissions from a grazed field estimated by miniDOAS measurements and inverse dispersion modelling. Atmos. Meas. Tech., 10, 1875–1892,

Bell M.W., Tang YS, Dragosits U., Flechard CR, Ward P, Braban CF (2016). Ammonia emissions from an anaerobic digestion plant estimated using atmospheric measurements and dispersion modelling. Waste Management 56: 113–124,

Buysse, P., Flechard, C.R., Hamon, Y., Viaud, V. (2016). Impacts of water regime and land-use on soil CO2 efflux in a small temperate agricultural catchment. Biogeochemistry 130, 3, 267-288,

Häni, C, C.R. Flechard , A. Neftel, J. Sintermann and T. Kupper (2018). Accounting for Field-Scale Dry Deposition in Backward Lagrangian Stochastic Dispersion Modelling of NH3 Emissions. Atmosphere 2018, 9, 146,

Bertolini, T.; Flechard, C.R.; Fattore, F.; Nicolini, G.; Stefani, P.; Materia, S.; Valentini, R.; Laurin, G.V.; Castaldi, S. (2016). Dry and bulk atmospheric nitrogen deposition to a West-African humid forest exposed to terrestrial and oceanic sources. Agricultural and Forest Meteorology. 218, 184-195,

Puche, N., Senapati, N., Flechard, C.R., Klumpp, K., Kirschbaum, M.U.F. and Chabbi, A. (2019). Modeling Carbon and Water Fluxes of Managed Grasslands: Comparing Flux Variability and Net Carbon Budgets between Grazed and Mowed Systems. Agronomy 2019, 9, 183;

See also

All productions by Christophe FLECHARD