@Article{HilkerGAMALWAFASPTCSWGORG:2017:VeChEs,
author = "Hilker, Thomas and Galv{\~a}o, L{\^e}nio Soares and Arag{\~a}o,
Luiz Eduardo Oliveira e Cruz de and Moura, Yhasmin Mendes de and
Amaral, Cibele H. do and Lyapustin, Alexei I. and Wu, Jin Wu and
Albert, Loren P. and Ferreira, Marciel Jos{\'e} and Anderson,
Liana O. and Santos, Victor A. H. F. dos and Prohaska, Neill and
Tribuzy, Edgard and Ceron, Jo{\~a}o Vitor Barbosa and Saleska,
Scott R. and Wang, Yujie and Gon{\c{c}}alves, Jos{\'e} Francisco
de Carvalho and Oliveira J{\'u}nior, Raimundo Cosme de and
Rodrigues, Jo{\~a}o Victor Figueiredo Cardoso and Garcia,
Maquelle Neves",
affiliation = "{University of Southampton} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais
(INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universidade Federal de Vi{\c{c}}osa (UFV)} and {NASA Goddard
Space Flight Center} and {Brookhaven National Lab} and {University
of Arizona} and {Universidade Federal do Amazonas (UFAM)} and
{Centro Nacional de Monitoramento e Alertas de Desastres Naturais
(CEMADEN)} and {Instituto Nacional de Pesquisas da Amaz{\^o}nia
(INPA)} and {University of Arizona} and {Instituto Nacional de
Pesquisas da Amaz{\^o}nia (INPA)} and {Instituto Nacional de
Pesquisas da Amaz{\^o}nia (INPA)} and {University of Arizona} and
{University of Maryland Baltimore County} and {Instituto Nacional
de Pesquisas da Amaz{\^o}nia (INPA)} and {Empresa Brasileira de
Pesquisa Agropecu{\'a}ria (EMBRAPA)} and {Universidade Federal do
Amazonas (UFAM)} and {Instituto Nacional de Pesquisas da
Amaz{\^o}nia (INPA)}",
title = "Vegetation chlorophyll estimates in the Amazon from multi-angle
MODIS observations and canopy reflectance model",
journal = "International Journal of Applied Earth Observation and
Geoinformation",
year = "2017",
volume = "58",
pages = "278--287",
month = "June",
keywords = "Chlorophyll, Phenology, Amazon, MODIS, Hyperspectral, ProSAIL,
Multi-angular.",
abstract = "As a preparatory study for future hyperspectral missions that can
measure canopy chemistry, we introduce a novel approach to
investigate whether multi-angle Moderate Resolution Imaging
Spectroradiometer (MODIS) data can be used to generate a
preliminary database with long-term estimates of chlorophyll.
MODIS monthly chlorophyll estimates between 2000 and 2015, derived
from a fully coupled canopy reflectance model (ProSAIL), were
inspected for consistency with eddy covariance fluxes, tower based
hyperspectral images and chlorophyll measurements. MODIS
chlorophyll estimates from the inverse model showed strong
seasonal variations across two flux-tower sites in central and
eastern Amazon. Marked increases in chlorophyll concentrations
were observed during the early dry season. Remotely sensed
chlorophyll concentrations were correlated to field measurements
(r(2) = 0.73 and r(2) = 0.98) but the data deviated from the 1:1
line with root mean square errors (RMSE) ranging from 0.355 g
cm(-2) (Tapajos tower) to 0.470 g cm(-2) (Manaus tower). The
chlorophyll estimates were consistent with flux tower measurements
of photosynthetically active radiation (PAR) and net ecosystem
productivity (NEP). We also applied ProSAIL to mono-angle
hyperspectral observations from a camera installed on a tower to
scale modeled chlorophyll pigments to MODIS observations (r(2) =
0.73). Chlorophyll pigment concentrations (Chl(A+B)) were
correlated to changes in the amount of young and mature leaf area
per month (0.59 <= r(2) <= 0.64). Increases in MODIS observed
Chl(A+B) were preceded by increased PAR during the dry season
(0.61 <r(2) < 0.62) and followed by changes in net carbon uptake.
We conclude that, at these two sites, changes in LAI, coupled with
changes in leaf chlorophyll, are comparable with seasonality of
plant productivity. Our results allowed the preliminary
development of a 15-year time series of chlorophyll estimates over
the Amazon to support canopy chemistry studies using future
hyperspectral sensors.",
doi = "10.1016/j.jag.2017.01.014",
url = "http://dx.doi.org/10.1016/j.jag.2017.01.014",
issn = "0303-2434",
language = "en",
targetfile = "hilker_vegetation.pdf",
urlaccessdate = "27 abr. 2024"
}