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Hétérogénéité spatiale des surfaces terrestres en télédétection : caractérisation et influence sur l'estimation des variables biophysiques

Abstract : Biophysical variable estimates from remote sensing data characterize plant canopy structure and functioning. The monitoring of earth surface dynamic processes at global scale requires high temporal frequency remote sensing observations which are provided up to now thanks to coarse spatial resolution sensors. At these scales, both the spatial heterogeneity of the observed scenes and the non linearity of the relationships between the biophysical variable of interest and the radiometric data, generate a bias in the variable estimation. This work aims at reducing the biophysical variable estimation uncertainty due to scaling effects. Spatial heterogeneity is characterized by the variogram of high spatial resolution remote sensing data (NDVI, NIR, RED). The analysis is performed for different landscapes. Typical length scales as measured by the range of the variogram is between 50m and 800m. Then, a method is developed to reduce scaling effects in the estimates of the biophysical variable. It accounts for spatial heterogeneity within coarse resolution pixel and the degree of non linearity of the relationship between remote sensed data and biophysical variable. Results show good performance for coarse resolution sensors. Based on the characterization of heterogeneity over a large range of landscapes (18), the optimal resolution, i.e the resolution that would minimize the artefacts due to spatial heterogeneity, is estimated at 30m.
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https://tel.archives-ouvertes.fr/tel-00010425
Contributor : Sebastien Garrigues <>
Submitted on : Wednesday, October 5, 2005 - 9:53:29 PM
Last modification on : Sunday, June 7, 2020 - 2:13:36 AM
Long-term archiving on: : Friday, April 2, 2010 - 10:07:31 PM

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  • HAL Id : tel-00010425, version 1
  • PRODINRA : 318757

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Sébastien Garrigues. Hétérogénéité spatiale des surfaces terrestres en télédétection : caractérisation et influence sur l'estimation des variables biophysiques. Autre. Agrocampus - Ecole nationale supérieure d'agronomie de renneS, 2004. Français. ⟨tel-00010425⟩

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