@Article{MouraHLGSASA:2015:SeDrEf,
author = "Moura, Yhasmin Mendes de and Hilker, Thomas and Lyapustin, Alexei
I. and Galv{\~a}o, L{\^e}nio Soares and Santos, Jo{\~a}o
Roberto dos and Anderson, Liana O. and Sousa, C{\'e}lio Helder
Resende de and Arai, Egidio",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Oregon
State University} and {NASA Goddard Space Flight Center} and
{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {University of Oxford}
and {Oregon State University} and {Instituto Nacional de Pesquisas
Espaciais (INPE)}",
title = "Seasonality and drought effects of Amazonian forests observed from
multi-angle satellite data",
journal = "Remote Sensing of Environment",
year = "2015",
volume = "171",
pages = "278--290",
month = "Dec.",
keywords = "Amazon, Drought, Anisotropy, Greening, Browning, MAIAC, MODIS.",
abstract = "Seasonality and drought in Amazon rainforests have been
controversially discussed in the literature, partially due to a
limited ability of current remote sensing techniques to detect its
impacts on tropical vegetation. We use a multi-angle remote
sensing approach to determine changes in vegetation structure from
differences in directional scattering (anisotropy) observed by the
Moderate Resolution Imaging Spectroradiometer (MODIS) with data
atmospherically corrected by the Multi-Angle Implementation
Atmospheric Correction Algorithm (MAIAC). Our results show a
strong linear relationship between anisotropy and field (r2 =
0.70) and LiDAR (r2 = 0.88) based estimates of LAI even in dense
canopies (LAI \≤ 7 m2 m\− 2). This allowed us to
obtain improved estimates of vegetation structure from optical
remote sensing. We used anisotropy to analyze Amazon seasonality
based on spatially explicit estimates of onset and length of dry
season obtained from the Tropical Rainfall Measurement Mission
(TRMM). An increase in vegetation greening was observed during the
beginning of dry season (across ~ 7% of the basin), which was
followed by a decline (browning) later during the dry season
(across ~ 5% of the basin). Anomalies in vegetation browning were
particularly strong during the 2005 and 2010 drought years (~ 10%
of the basin). We show that the magnitude of seasonal changes can
be significantly affected by regional differences in onset and
duration of the dry season. Seasonal changes were much less
pronounced when assuming a fixed dry season from June through
September across the Amazon Basin. Our findings reconcile remote
sensing studies with field based observations and model results as
they provide a sounder basis for the argument that tropical
vegetation growth increases during the beginning of the dry
season, but declines after extended drought periods. The
multi-angle approach used in this work may help quantify drought
tolerance and seasonality in the Amazonian forests.",
doi = "10.1016/j.rse.2015.10.015",
url = "http://dx.doi.org/10.1016/j.rse.2015.10.015",
issn = "0034-4257",
language = "en",
urlaccessdate = "03 jun. 2024"
}