Synthetic aperture radar (L band) and optical vegetation indices for discriminating the brazilian savanna physiognomies: a comparative analysis
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Data
2005
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Resumo
The all-weather capability, signal independence to the solar
illumination angle, and response to 3D vegetation structures are the highlights
of active radar systems for natural vegetation mapping and monitoring. However,
they may present significant soil background effects. This study addresses
a comparative analysis of the performance of L-band synthetic aperture radar
(SAR) data and optical vegetation indices (VIs) for discriminating the Brazilian
cerrado physiognomies. The study area was the Brasilia National Park, Brazil, one of the test sites of the Large-Scale Biosphere–Atmosphere (LBA) experiment
in Amazonia. Seasonal Japanese Earth Resources Satellite-1 (JERS-1)
SAR backscatter coefficients ( °) were compared with two vegetation indices
[normalized difference vegetation index (NDVI) and enhanced vegetation index
(EVI)] over the five most dominant cerrados’ physiognomies plus gallery
forest. In contrast to the VIs, ° from dry and wet seasons did not change
significantly, indicating primary response to vegetation structures. Discriminant
analysis and analysis of variance (ANOVA) showed an overall higher
performance of radar data. However, when both SAR and VIs are combined,
the discrimination capability increased significantly, indicating that the fusion
of the optical and radar backscatter observations provides overall improved
classifications of the cerrado types. In addition, VIs showed good performance
for monitoring the cerrado dynamics.
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Palavras-chave
Cerrado monitoring, Vegetation index, SAR
Citação
SANO, Edson E.; FERREIRA, Laerte .G.; HUETE, Alfredo R. Synthetic aperture radar (L band) and optical vegetation indices for discriminating the brazilian savanna physiognomies: a comparative analysis. Earth Interactions, New York, v. 9, n. 15, p. 1-15, 2005.