Volatile organic compounds sources and sinks in a wheat canopy. Analysis based on combined eddy-covariance fluxes, in-canopy profiles and chamber measurements with a PTR-TOF-Qi-MS
Résumé
Volatile organic compounds (VOC) are essential drivers of atmospheric
chemistry. Many VOCs are emitted from and deposited to ecosystems. While
forests and grasslands have already been substantially studied,
exchanges of VOCs with crops are less known, although these ecosystems
represent more than 50% of the surface in France. In this study, we
analyze sources and sinks of VOCs in a wheat field (at the ICOS FR-GRI
site near Paris) at anthesis based on measurements of fluxes,
concentration profiles and branch chambers. The VOCs were measured using
a PTR-TOF-Qi-MS (where Qi stands for Quad Ion guide). Air was
successively sampled through lines located at different heights within
and above the canopy, of which one was used for Eddy Covariance and
located near a sonic anemometer. Additional measurements included the
standard ICOS meteorological data as well as leaf area index profiles
and photosynthesis curves at several heights in the canopy. We report
fluxes and profiles for more than 500 VOCs. The deposition velocities of
depositing compounds are compared to the maximum exchange velocity and
the ozone deposition velocity. The sources and sinks location and
magnitude are evaluated by inverse Lagrangian modelling assuming no
reaction and simple reaction schemes in the canopy. The sources and
sinks of VOC in the canopy are interpreted in terms crop phenology and
the potential for reaction with ozone and NOx is evaluated. This study
takes place in the ADEME CORTEA COV3ER French project
(http://www6.inra.fr/cov3er).
Auteurs, date et publication :
Auteurs Benjamin Loubet , Lais Gonzaga , Pauline Buysse , Raluca Ciuraru , Florence Lafouge , Céline Decuq , Olivier Zurfluh , Alain Fortineau , Olivier Fanucci , Roland Sarda-Esteve , Nora Zannoni , Francois Truong , Christophe Boissard , Valérie Gros
Date : 2017
Volume : 19
Pages : 15566