Estimation of LAI and FAPAR by constraining the leaf and soil spectral characteristics in a radiative transfer model
Estimation of LAI and FAPAR by constraining the leaf and soil spectral characteristics in a radiative transfer model
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DOI：
10.1080/01431160902998367
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发表时间：
2010-01-01
影响因子：
3.4
通讯作者：
Yoshino, Kunihiko
中科院分区：
文献类型：
--
作者：
Kushida, Keiji;Yoshino, Kunihiko
利用PROSAIL模式，在叶片光谱和土壤光谱约束条件下，利用TOC光谱指数估算绿色植物冠层叶面积指数（LAI）和光合有效辐射吸收率（FAPAR）。对于叶面积指数的估算，当土壤光谱反射率变化较小或叶面积指数较大时，（B1-B3）/（B1+B3）和B1/B3比（B4-B3）/（B4+B3）或B4/B3的估算误差小。这里，B1、B3和B4分别表示Landsat ETM+的蓝色、红色和近红外波段。对于FAPAR估算，当土壤光谱反射率的变化较大时，比值（B5 -B7）/（B5+B7）和B5/B7提供的估算误差小于比值（NIR-R）/（NIR +R）或NIR/R，FAPAR值为0.3-0.7。这里，B5和B7分别表示波长为1.55-1.75和2.09-2.35 μ m的波段。这些都保持了太阳入射天顶角（θ（s）），叶角分布（LAD），冠层热点参数（s（1））和丛生指数（Ω）的各种条件。
We evaluated the estimation of the leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (FAPAR) of green plant canopies from top-of-the-canopy (TOC) spectral indices by using the PROSAIL model under the possible constraints of leaf and soil spectra. For the LAI estimation, the ratios (B1-B3)/(B1+B3) and B1/B3 provided fewer estimation errors than (B4-B3)/(B4+B3) or B4/B3 when the variation in the soil spectral reflectance was small or LAI was large. Here, B1, B3 and B4 denote the blue, red and near-infrared bands of Landsat ETM+, respectively. For the FAPAR estimation, the ratios (B5 -B7)/(B5+B7) and B5/B7 provided fewer estimation errors than (NIR-R)/(NIR +R) or NIR/R for a FAPAR value of 0.3-0.7 when the variation in the soil spectral reflectance was large. Here, B5 and B7 denote the bands with wavelengths 1.55-1.75 and 2.09-2.35 mu m, respectively. These were maintained for various conditions of the solar incident zenith angle (theta(s)), leaf angle distribution (LAD), canopy hotspot parameter (s(1)) and clumping index (Omega).