Seasonal landscape and spectral vegetation index dynamics in the brazilian Cerrado: an analysis within the large-scale biosphere–atmosphere experiment in Amazônia (LBA)
Carregando...
Data
2003-11
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
The Brazilian Cerrado biome comprises a vertically structured mosaic of grassland, shrubland, and woodland physiognomies with distinct
phenology patterns. In this study, we investigated the utility of spectral vegetation indices in differentiating these physiognomies and in
monitoring their seasonal dynamics. We obtained high spectral resolution reflectances, during the 2000 wet and dry seasons, over the major
Cerrado types at Brasilia National Park (BNP) using the light aircraft-based Modland Quick Airborne Looks (MQUALS) package, consisting
of a spectroradiometer and digital camera. Site-intensive biophysical and canopy structural measurements were made simultaneously at each
of the Cerrado types including Cerrado grassland, shrub Cerrado, wooded Cerrado, Cerrado woodland, and gallery forest. We analyzed the
spectral reflectance signatures, their first derivative analogs, and convolved spectral vegetation indices (VI) over all the Cerrado
physiognomies. The high spectral resolution data were convolved to the MODIS, AVHRR, and ETM+ bandpasses and converted to the
normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) to simulate their respective sensors. Dry and wet
season comparisons of the measured biophysical attributes were made with the reflectance and VI data for the different Cerrado
physiognomies. We found that three major domains of Cerrado could be distinguished with the dry and wet season spectral signatures and
vegetation indices. The EVI showed a higher sensitivity to seasonality than the NDVI; however, both indices displayed seasonal variations
that were approximately one-half that found with the measured landscape green cover dynamics. Inter-sensor comparisons of seasonal
dynamics, based on spectral bandpass properties, revealed the ETM+-simulated VIs had the best seasonal discrimination capability, followed
by MODIS and AVHRR. Differences between sensor bandpass-derived VI values, however, varied with Cerrado type and between dry and
wet seasons, indicating the need for inter-sensor VI translation equations for effective multi-sensor applications.
Descrição
Palavras-chave
Citação
FERREIRA, L.G.; H., Yoshioka; HUETE, A. R.; SANO, E. E. Seasonal landscape and spectral vegetation index dynamics in the brazilian Cerrado: an analysis within the large-scale biosphere–atmosphere experiment in Amazônia (LBA). Remote Sensing of Environment, Amsterdam, v. 87, n. 4, p. 534-550, Nov. 2003.