Preliminary Results from the FARCE 2015 Campaign: Multidisciplinary Study of the Forest–gas–aerosol–cloud System on the Tropical Island of La Réunion


Valentin Duflot, Université de la Réunion
Pierre Tulet, Université de la Réunion
Olivier Flores, Peuplements Végétaux et Bioagresseurs en Milieu Tropical
Christelle Barthe, Université de la Réunion
Aurélie Colomb, Université Clermont Auvergne
Laurent Deguillaume, Université Clermont Auvergne
Mickael Vaïtilingom, Université des Antilles
Anne Perring, National Oceanic and Atmospheric Administration,Cooperative Institute for Research in Environmental Science
J. Alex Huffman, University of DenverFollow
Mark T. Hernandez, University of Colorado Boulder
Karine Sellegri, Université Clermont Auvergne
Ellis Robinson, National Oceanic and Atmospheric Administration,Cooperative Institute for Research in Environmental Science
David J. O'Connor, Technological University Dublin
Odessa M. Gomez, University of Colorado Boulder
Frédéric Burnet, Centre National de la Recherche Météorologique
Thierry Bourrianne, Centre National de la Recherche Météorologique
Dominique Strasberg, Peuplements Végétaux et Bioagresseurs en Milieu Tropical
Manon Rocco, Université Clermont Auvergne
Allan K. Bertram, University of British Columbia
Patrick Chazette, Université de Versailles Saint-Quentin-en-Yvelines
Julien Totems, Université de Versailles Saint-Quentin-en-Yvelines
Jacques Fournel, Peuplements Végétaux et Bioagresseurs en Milieu Tropical
Pierre Stamenoff, Observatoire des Sciences de l'Univers de La Réunion
Jean-Marc Metzger, Observatoire des Sciences de l'Univers de La Réunion
Mathilde Chabasset, Université de la Réunion
Clothilde Rousseau, Université de la Réunion
Eric Bourrianne, Université de la Réunion
Martine Sancelme, Université Clermont Auvergne
Anne-Marie Delort, Université Clermont Auvergne
Rachel E. Wegener, University of Denver
Cedric Chou, University of British Columbia
Pablo Elizondo, University of British Columbia

Publication Date


Document Type


Organizational Units

Chemistry and Biochemistry


Soil air, Mountain soils, Air masses, Volatile organic compounds, Boundary layer, Wind shear, Shear zones


The Forests gAses aeRosols Clouds Exploratory (FARCE) campaign was conducted in March–April 2015 on the tropical island of La Réunion. For the first time, several scientific teams from different disciplines collaborated to provide reference measurements and characterization of La Réunion vegetation, volatile organic compounds (VOCs), biogenic VOCs (BVOCs), (bio)aerosols and composition of clouds, with a strong focus on the Maïdo mountain slope area. The main observations obtained during this 2-month intensive field campaign are summarized. They include characterizations of forest structure, concentrations of VOCs and precursors emitted by forests, aerosol loading and optical properties in the planetary boundary layer (PBL), formation of new particles by nucleation of gas-phase precursors, ice-nucleating particles concentrations, and biological loading in both cloud-free and cloudy conditions. Simulations and measurements confirm that the Maïdo Observatory lies within the PBL from late morning to late evening and that, when in the PBL, the main primary sources impacting the Maïdo Observatory are of marine origin via the Indian Ocean and of biogenic origin through the dense forest cover. They also show that (i) the marine source prevails less and less while reaching the observatory; (ii) when in the PBL, depending on the localization of a horizontal wind shear, the Maïdo Observatory can be affected by air masses coming directly from the ocean and passing over the Maïdo mountain slope, or coming from inland; (iii) bio-aerosols can be observed in both cloud-free and cloudy conditions at the Maïdo Observatory; (iv) BVOC emissions by the forest covering the Maïdo mountain slope can be transported upslope within clouds and are a potential cause of secondary organic aerosol formation in the aqueous phase at the Maïdo Observatory; and (v) the simulation of dynamics parameters, emitted BVOCs and cloud life cycle in the Meso-NH model are realistic, and more advanced Meso-NH simulations should use an increased horizontal resolution (100 m) to better take into account the orography and improve the simulation of the wind shear front zone within which lies the Maïdo Observatory. Using various observations and simulations, this work draws up an inventory of the in situ studies that could be performed in La Réunion and at the Maïdo Observatory. It also aims to develop scientific collaborations and to support future scientific projects in order to better understand the forest–gas–aerosol–cloud system in an insular tropical environment.

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