Hyperspectral indices based on first derivative spectra closely trace canopy transpiration in a desert plant
Hyperspectral indices based on first derivative spectra closely trace canopy transpiration in a desert plant
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基于一阶导数光谱的高光谱指数密切追踪沙漠植物的冠层蒸腾作用
DOI：
10.1016/j.ecoinf.2016.06.004
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发表时间：
2016-09-01
影响因子：
5.1
通讯作者：
Wang, Quan
中科院分区：
文献类型：
--
作者：
Jin, Jia;Wang, Quan
清楚地了解干旱生态系统的蒸腾作用及其潜在机制对于准确预测此类生态系统的长期水和能量通量至关重要，人们逐渐认识到干旱生态系统在全球范围内发挥着重要作用。与通常耗时、昂贵且往往不可行的传统蒸腾测量不同，高光谱指数等遥感技术被广泛用作大规模获取此类信息的唯一方法。然而，与其他生化和生物物理参数相比，很少有关于高光谱指数的研究被应用于估计冠层蒸腾作用。在这项研究中，我们重点关注中亚干旱地区的原生优势植物梭梭，探索其特征光谱并开发适当的高光谱指数来估计蒸腾作用。这是基于原始冠层反射光谱及其一阶导数的同步数据集，其中蒸腾作用是根据液流估计的。结果表明，与基于原始反射率的指数相比，基于导数光谱的指数对于追踪冠层蒸腾作用更有效。基于一阶导数光谱确定的估算冠层蒸腾作用的最佳指数是 dSR(660,1040)，其决定系数 (R-2) 为 0.54。该指数在光谱分辨率方面也相对稳定。本研究获得的结果应有助于为利用遥感数据估算蒸腾量奠定基础。 (C) 2016 Elsevier B.V. 保留所有权利。
A clear understanding of transpiration of arid ecosystems and its underlying mechanisms is critical for accurate prediction of long-term water and energy fluxes in such ecosystems, which have gradually been recognized to play major roles on a global scale. Unlike traditional measurements of transpiration that are generally time-consuming, expensive, and often unfeasible, remote sensing techniques such as hyperspectral indices are widely utilized as the only approach to obtain such information on a large scale. However, compared with other biochemical and biophysical parameters, few studies on hyperspectral indices have been applied to estimate canopy transpiration. In this study, we focused on a native dominant plant in the arid land of central Asia, Haloxylon ammodendron, to explore the featured spectra and to develop proper hyperspectral indices for estimating transpiration. This was based on a simultaneous dataset of original canopy-reflectance spectra as well as its first derivatives with transpiration estimated from sap flow. The results indicated that the derivative spectra-based indices are more effective for tracing canopy transpiration, compared with its counterpart that was based on the original reflectance. The identified best index for estimating canopy transpiration was dSR(660,1040) based on the first-derivative spectra, which had a coefficient of determination (R-2) of 0.54. The index is also relatively stable concerning spectral resolutions. Results obtained in this study should help lay the basis for using remote sensing data to estimate transpiration. (C) 2016 Elsevier B.V. All rights reserved.