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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Relationship between leaf area index and endmember fractions from linear spectral mixture modelling, using ETM+/Landsat images

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Author(s):
Alexandre C. Xavier [1] ; Carlos A. Vettorazzi [2] ; Ronalton E. Machado [3]
Total Authors: 3
Affiliation:
[1] Instituto Nacional de Pesquisas Espaciais. Divisão de Sensoriamento Remoto
[2] USP. ESALQ. Departamento de Engenharia Rural
[3] USP. ESALQ. Departamento de Engenharia Rural
Total Affiliations: 3
Document type: Journal article
Source: Engenharia Agrícola; v. 24, n. 2, p. 421-430, 2004-08-00.
Abstract

The Leaf Area Index (LAI) is one of the most important biophysical variable of the vegetation for modeling, and it is directly related to evapotranspiration, vegetation yield and rain interception. The aim of this paper was to analyze the relationship between LAI and endmember fractions estimated by Linear Spectral Mixture Modelling (LSMM). The study area was a watershed, in Piracicaba, State of São Paulo, Brazil. LAI was measured with LAI-2000 equipment in 32 samples in the field with different vegetation cover. The LSMM was applied to a Landsat/ETM+ image, corrected for the atmospheric effects by 6S Model. Three endmembers were considered in the LSMM: vegetation, soil, and shade. The relationship between all LAIs and vegetation and soil fractions (FVG and FSO) were significant, although weak. The relationship between sugar-cane LAI with FVG and with FSO showed better fits. These results indicated that the vegetation type had influenced on the LSMM and that the stratification by vegetation physiognomy is suggested to improve the LAI estimation. Relationship between LAI and shadow fraction was not statistically significant. (AU)