Title: Detection of large ragweed populations using remote sensing data
Abstract: Ragweed, Ambrosia artemisiifolia L., is an annual plant producing allergenic pollen. In 2005, about 20% of people living in the Rhône department (France) were affected by ragweed allergy. Six departments of the Rhône-Alpes Region are infested by this plant (Ain, Ardèche, Drôme, Isère, Loire and Rhône). Our goal is to validate a method for a yearly ragweed infestation mapping that could be used for alerting the population. During 2001–2005, experiments were carried out at the Rhône-Alpes Region. We have established the spectral reflectance of Ambrosia artemisiifolia L., which was different from other neighbouring species. Detection using remote sensing showed that large parcels were infested with ragweed. In 2001 and 2003, ground truth experiments, aim to delineate training sites of pure crop and very infested zones, were realized in small areas around Lyon (Saint-Priest, Rhône department, France). Terra Aster images (from June 23 and from August 13 2001) and Spot 4 image (from July 14 2003) were segregated using maximum likelihood classification. On these small areas, the method worked well: 90 % of pixels were correctly classified. In 2005, the last experiment was achieved in Estrablin, a village in Isère department, France, which covers a larger area. Up to 30% of cultivated land showed an indication of ragweed infestation. Using a Spot 5 multispectral satellite image acquired on August 16 2005, a maximum likelihood classification was based on classes crossing the type of crop with the infestation importance. The accuracy of the proposed method was demonstrated through the clearness of visual representations. [Yves Auda, Chantal Déchamp, Henriette Méon, David Duisit, Jean-Luc Pontier, Solofoarisoa Rakotoniaina (2011). Detection of large ragweed populations using remote sensing data. In: Clot B, Comtois P, Escamilla-Garcia B (Eds.). 2011. Aerobiological Monographs, Towards a comprehensive vision. MeteoSwiss (CH) and University of Montreal (CA), Montreal, Canada, 1:3 5.]
Keywords: Ambrosia artemisiifolia L., common ragweed, France, remote sensing