A note on upscaling coniferous needle spectra to shoot spectral albedo
A note on upscaling coniferous needle spectra to shoot spectral albedo
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DOI：
10.1016/j.rse.2011.10.019
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发表时间：
2012-02-15
影响因子：
13.5
通讯作者：
Schaepman, Michael E.
中科院分区：
文献类型：
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作者：
Rautiainen, Miina;Mottus, Matti;Schaepman, Michael E.
针叶树新梢中针叶的相互遮蔽以及新梢内部和新梢之间针叶面积密度的小尺度变化，都违背了辐射传输模型中基本体积定义所采用的常规假设。在本文中，我们检验这样一个假设：是否有可能仅使用一个结构参数，即球形平均新梢轮廓与总面积之比（STAR），将针叶光谱反照率放大到新梢光谱反照率。为了检验该假设，我们测量了10个欧洲赤松（Pinus sylvestris）新梢及其针叶的结构和光谱特性。我们的结果表明，使用STAR可以将针叶光谱反照率放大到新梢光谱反照率。该放大模型在可见光（VIS）和短波红外（SWIR）区域以及对于具有高STAR值的新梢效果最佳。由于STAR与光子再碰撞概率呈线性相关，因此也有可能将该放大模型作为辐射传输模型的组成部分加以应用。（C）2011爱思唯尔公司。保留所有权利。
Mutual shading of needles in coniferous shoots and small-scale variations in needle area density both within and between shoots violate conventional assumptions used in the definition of the elementary volume in radiative transfer models. In this paper, we test the hypothesis if it is possible to scale needle spectral albedo up to shoot spectral albedo using only one structural parameter: the spherically averaged shoot silhouette to total area ratio (STAR). To test the hypothesis, we measured both structural and spectral properties of ten Scots pine (Pinus sylvestris) shoots and their needles. Our results indicate that it is possible to upscale from needle to shoot spectral albedo using STAR. The upscaling model performed best in the VIS and SWIR regions, and for shoots with high STAR values. As STAR is linearly related to photon recollision probability, it is also possible to apply the upscaling model as integral part of radiative transfer models. (C) 2011 Elsevier Inc. All rights reserved.