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Suivi multi-échelle par télédétection et spectroscopie de l'état hydrique de la végétation méditerranéenne pour la prévention du risque de feu de forêt

Abstract : In south-eastern France, forest fire hazard is assessed using two methods: through meteorological fire indices, spatialized by Meteo-France on sub-regions of an average size of 700 km2 and through the measurement of fuel moisture content (FMC) carried out by ONF, the French forestry board, on plots below 500 m2. The latter protocol derives from the fact that FMC plays a major role in the fire ignition (inflammability) and fire spread (combustibility) hazards. Up to now the use of satellite images for the spatialization of fuel moisture content is difficult because of a lack of validation due the difference in scale between the square kilometer of satellite data and the small size of FMC plots. Our work aims at validating satellite data using multi-scale FMC measurements. We use different field schemes with varying scales, from decameter to kilometer, to assess the spatial and temporal variabilities of the Mediterranean vegetation moisture content. This leads to the proposition of sampling schemes adapted to FMC assessment, FMC to be compared to the radiometric signal reflected by vegetation. A first work is carried out at leaf level using NIRS spectrometry and demonstrates the interest of using the short wave infrared part of the electromagnetic spectrum for leaf FMC assessment. In a second phase, we change the observation scale and use remote sensing data to assess forest stand FMC. The results obtained at high resolution (using SPOT-HRVIR data) and low resolution (using AVHRR, VEGETATION et MODIS data) are heterogeneous because atmospheric and radiometric effects are only partially corrected. In a near future, progress are expected in the processing of these disturbing effects. Remote sensing will then become an efficient means for the spatialization of FMC content allowing a better mapping of forest fire hazard.
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https://pastel.archives-ouvertes.fr/pastel-00000803
Contributor : Ecole Agroparistech <>
Submitted on : Tuesday, January 11, 2005 - 8:00:00 AM
Last modification on : Tuesday, October 20, 2020 - 3:29:43 AM
Long-term archiving on: : Wednesday, March 29, 2017 - 6:30:18 PM

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  • HAL Id : pastel-00000803, version 1

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Fabien Dauriac. Suivi multi-échelle par télédétection et spectroscopie de l'état hydrique de la végétation méditerranéenne pour la prévention du risque de feu de forêt. Hydrologie. ENGREF (AgroParisTech), 2004. Français. ⟨NNT : 2004ENGR0009⟩. ⟨pastel-00000803⟩

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