@Article{BreunigGaSaGiMoTeGa:2015:SpAnSu,
author = "Breunig, F{\'a}bio Marcelo and Galv{\~a}o, L{\^e}nio Soares and
Santos, Jo{\~a}o Roberto dos and Gitelson, Anatoly A. and Moura,
Yhasmin Mendes de and Teles, Thiago Sousa and Gaida, William",
affiliation = "{Universidade Federal de Santa Maria (UFSM)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {University of Nebraska} and
{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Federal
de Santa Maria (UFSM)}",
title = "Spectral anisotropy of subtropical deciduous forest using MISR and
MODIS data acquired under large seasonal variation in solar zenith
angle",
journal = "International Journal of Applied Earth Observation and
Geoinformation",
year = "2015",
volume = "35",
number = "part B",
pages = "294--304",
month = "Mar.",
keywords = "MISR, MODIS, View-illumination geometry, NDVI, EVI, PROSAIL.",
abstract = "Recent studies in Amazonian tropical evergreen forests using the
Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate
Resolution Imaging Spectroradiometer (MODIS) have highlighted the
importance of considering the view-illumination geometry in
satellite data analysis. However, contrary to the observed for
evergreen forests, bidirectional effects have not been evaluated
in Brazilian subtropical deciduous forests. In this study, we used
MISR data to characterize the reflectance and vegetation index
anisotropies in subtropical deciduous forest from south Brazil
under large seasonal solar zenith angle (SZA) variation and
decreasing leaf area index (LAI) from the summer to winter. MODIS
data were used to observe seasonal changes in the normalized
difference vegetation index (NDVI) and enhanced vegetation index
(EVI). Topographic effects on their determination were inspected
by dividing data from the summer to winter and projecting results
over a digital elevation model (DEM). By using the PROSAIL, we
investigated the relative contribution of LAI and SZA to
vegetation indices (VI) of deciduous forest. We also simulated and
compared the MISR NDVI and EVI response of subtropical deciduous
and tropical evergreen forests as a function of the large seasonal
SZA amplitude of 33°. Results showed that the MODIS-MISR NDVI and
EVI presented higher values in the summer and lower ones in the
winter with decreasing LAI and increasing SZA or greater amounts
of canopy shadows viewed by the sensors. In the winter, NDVI
reduced local topographic effects due to the red-near infrared
(NIR) band normalization. However, the contrary was observed for
the three-band EVI that enhanced local variations in shaded and
sunlit surfaces due to its strong dependence on the NIR band
response. The reflectance anisotropy of the MISR bands increased
from the summer to winter and was stronger in the backscattering
direction at large view zenith angles (VZA). EVI was much more
anisotropic than NDVI and the anisotropy increased from the summer
to winter. It also increased from the forward scatter to the
backscattering direction with the predominance of sunlit canopy
components viewed by MISR, especially at large VZA. Modeling
PROSAIL results confirmed the stronger anisotropy of EVI than NDVI
for the subtropical deciduous and tropical evergreen forests.
PROSAIL showed that LAI and SZA are coupled factors to decrease
seasonally the VIs of deciduous forest with the first one having
greater importance than the latter. However, PROSAIL seasonal
variations in VIs were much smaller than those observed with MODIS
data probably because the effects of shadows in heterogeneous
canopy structures or/and cast by emergent trees and from local
topography were not modeled.",
doi = "10.1016/j.jag.2014.09.017",
url = "http://dx.doi.org/10.1016/j.jag.2014.09.017",
issn = "0303-2434",
language = "en",
targetfile = "Breunig_spectral.pdf",
urlaccessdate = "28 abr. 2024"
}