2024-03-28T16:18:21Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/102772016-10-10T06:52:58Zcom_10261_74com_10261_6col_10261_327
Zarco-Tejada, Pablo J.
Rueda, C. A.
Ustin, S. L.
2009-02-04T11:47:10Z
2009-02-04T11:47:10Z
2003
Remote Sensing of Environment, 85(1), 109-124
0034-4257
http://hdl.handle.net/10261/10277
10.1016/S0034-4257(02)00197-9
Statistical and radiative-transfer physically based studies have previously demonstrated the relationship between leaf water content and
leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling
the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of water content, such as
normalized difference water index (NDWI), simple ratio water index (SRWI) and plant water index (PWI). This study conducts a radiative
transfer simulation, linking leaf and canopy models, to study the effects of leaf structure, dry matter content, leaf area index (LAI), and the
viewing geometry, on the estimation of leaf equivalent water thickness from canopy-level reflectance. The applicability of radiative transfer
model inversion methods to MODIS is studied, investigating its spectral capability for water content estimation. A modeling study is
conducted, simulating leaf and canopy MODIS-equivalent synthetic spectra with random input variables to test different inversion
assumptions. A field sampling campaign to assess the investigated simulation methods was undertaken for analysis of leaf water content from
leaf samples in 10 study sites of chaparral vegetation in California, USA, between March and September 2000. MODIS reflectance data were
processed from the same period for equivalent water thickness estimation by model inversion linking the PROSPECT leaf model and SAILH
canopy reflectance model. MODIS reflectance data, viewing geometry values, and LAI were used as inputs in the model inversion for
estimation of leaf equivalent water thickness, dry matter, and leaf structure. Results showed good correlation between the time series of
MODIS-estimated equivalent water thickness and ground measured leaf fuel moisture (LFM) content (r2 = 0.7), demonstrating that these
inversion methods could potentially be used for global monitoring of leaf water content in vegetation.
eng
closedAccess
Radiative transfer
Water content
Leaf fuel moisture
Equivalent water thickness
MODIS
Reflectance
Model inversion
Water content estimation in vegetation with MODIS reflectance data and model inversion methods
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