Remote Sensing of Nitrogen and Carbon Isotope Compositions in Terrestrial Ecosystems
Remote Sensing of Nitrogen and Carbon Isotope Compositions in Terrestrial Ecosystems
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陆地生态系统中氮和碳同位素组成的遥感
DOI：
10.1007/978-90-481-3354-3_3
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发表时间：
2010
影响因子：
2.6
通讯作者：
S. Macko
中科院分区：
文献类型：
--
作者：
Lixin Wang;G. Okin;S. Macko
稳定同位素经常被用来指示土壤、植物和大气中从单个生物到整个生态系统的过程。另一方面，遥感是一种强有力的工具，用于在更大的尺度上确定生态系统的模式和过程。这两种方法的结合将有望对同位素组成进行空间连续的估计，从而为地球生态系统内的模式和过程提供前所未有的信息。然而，迄今为止，同位素与遥感技术的结合仍处于探索阶段。在这里，两个例子，一个利用高光谱分辨率遥感和其他采用高空间分辨率遥感，稳定同位素和遥感技术的集成建议作为可能的途径。首先，利用高分辨率的光谱数据来估计植被δ 15 N从叶片到冠层水平的可行性进行了测试。实验结果表明，在某些可见光和近红外波段，叶片δ 15 N与光谱反射率（R）之间存在很强的相关性。逐步回归分析表明，log 1/R的一阶差分解释了叶片δ 15 N变化的76-92%，在600和700 nm附近波段提供了最可靠的相关性。其次，如果植被-土壤δ 13 C关系可以在地面上量化，土壤δ 13 C分布可以通过高分辨率卫星估算。尽管存在局限性，但由于其非破坏性和连续性，遥感是扩大对陆地δ 15 N和δ 13 C空间格局和动态测量的一种有前途的工具。
Stable isotopes have been frequently used to indicate processes occurring in soils, plants, and the atmosphere at scales from individual organisms to an entire ecosystem. Remote sensing, on the other hand, is a powerful tool used to identify ecosystem patterns and processes at larger scales. A union of these two approaches would hold promise for spatially continuous estimates of isotope compositions, thus providing unprecedented information into the patterns and processes within the Earth’s ecosystems. To date, however, the combination of isotope and remote sensing techniques is still in the exploratory stage. Here, two examples, one utilizing high spectral resolution remote sensing and the other employing high spatial resolution remote sensing, are suggested as possible approaches for the integration of stable isotope and remote sensing techniques. First, the feasibility of using high-resolution spectral data to estimate the vegetation δ15N from leaf to canopy levels is tested. Experimental results have shown that there is a strong correlation between foliar δ15N and spectral reflectance (R) in certain visible and near-infrared wavelengths. Stepwise regression indicates that the first-difference of the log 1/R explains 76–92% of the variation in foliar δ15N, providing the most reliable correlations in bands near 600 and 700 nm. Second, if the vegetation-soil δ13C relationship can be quantified on ground, soil δ13C distribution can be estimated by high-resolution satellite. Although limitations exist, because of the non-destructive and continuous nature, remote sensing is a promising tool to expand measurements of terrestrial δ15N and δ13C spatial patterns and dynamics.