Spectral monitoring of moorland plant phenology to identify a temporal window for hyperspectral remote sensing of peatland
Spectral monitoring of moorland plant phenology to identify a temporal window for hyperspectral remote sensing of peatland
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DOI：
10.1016/j.isprsjprs.2014.01.010
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发表时间：
2014-04-01
影响因子：
12.7
通讯作者：
Evans, Martin
中科院分区：
文献类型：
--
作者：
Cole, Beth;McMorrow, Julia;Evans, Martin
在植被生态系统遥感中，认识到图像采集时间对光谱响应的重要性是至关重要的。本研究利用350-2500 nm的全波长野外光谱技术建立了高沼地关键物种的物候变化光谱库，并探讨了监测高地泥炭地系统的合适时间窗口。连续两个生长季节的光谱响应记录在单种地块的关键高沼地物种和物种播种恢复侵蚀泥炭。这是有关的物候变化，使用窄带植被指数（红边位置，光化学反射指数，植物衰老反射指数和纤维素吸收指数），捕捉绿化和衰老相关的变化，在可见光到近红外和短波红外吸收功能。通过确定整个光谱中捕获反射率的最大变化区域来确认指数的选择。这些指数显示了从4月到9月发生的物种之间的变化程度的变化，测量植物功能类型。指数和植物功能类型之间的判别函数分析确定每个指数能够区分每个月的植物功能组。它确定四月和七月是物种最容易分离的两个月。这里提出的不是一个单一的建议，业务监测的最佳时间窗口，但更全面地了解光谱响应如何变化的物候周期，包括建议什么指数是重要的全年。(C)2014年国际摄影测量与遥感学会（ISRS）由Elsevier B. V.发布保留所有权利。
Recognising the importance of the timing of image acquisition on the spectral response in remote sensing of vegetated ecosystems is essential. This study used full wavelength, 350-2500 nm, field spectroscopy to establish a spectral library of phenological change for key moorland species, and to investigate suitable temporal windows for monitoring upland peatland systems. Spectral responses over two consecutive growing seasons were recorded at single species plots for key moorland species and species sown to restore eroding peat. This was related to phenological change using narrowband vegetation indices (Red Edge Position, Photochemical Reflectance Index, Plant Senescence Reflection Index and Cellulose Absorption Index); that capture green-up and senescence related changes in absorption features in the visible to near infrared and the shortwave infrared. The selection of indices was confirmed by identifying the regions of maximum variation in the captured reflectance across the full spectrum. The indices show change in the degree of variation between species occurring from April to September, measured for plant functional types. A discriminant function analysis between indices and plant functional types determines how well each index was able to differentiate between the plant functional groups for each month. It identifies April and July as the two months where the species are most separable. What is presented here is not one single recommendation for the optimal temporal window for operational monitoring, but a fuller understanding of how the spectral response changes with the phenological cycle, including recommendations for what indices are important throughout the year. (C) 2014 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier B.V. All rights reserved.