Detection of vegetation canopy stress dynamics using integrated near-ground, and airborne remote sensing data over coastal and boreal forests

监测植物光合作用是了解陆地碳循环的一个关键组成部分，需要详细了解植被覆盖的陆地表面。遥感是以空间连续方式观测植被特征的理想技术，然而，植被生长随时间和空间的变化需要关于土壤水分和养分状况以及气候的额外信息。这项研究计划将开发植被反射率（指示植被功能），植物光利用效率（芸香）和碳和水通量的同步测量之间的函数关系。我们的方法侧重于确定和监测芸香使用遥感衍生的光化学反射指数（PRI，（基于冠层反射率在531和570 nm）和其他光谱指数。在冠层尺度上对芸香进行建模并不简单，因为PRI是定向反射率和植物生理状态的函数。为了解决这些复杂性，我们设计并建造了一个创新的塔式传感器（AMSPEC），它每15秒扫描一次树冠顶部，记录叶片功能的变化。

Monitoring of plant photosynthesis is a critical component to understanding the terrestrial carbon cycle, and requires a detailed understanding of the vegetated land surface. Remote sensing is the ideal technology to observe vegetation characteristics in a spatially continuous mode, however variations in vegetation growth over space and time, requires additional information on soil water and nutrient status and climate. This research program will develop functional relationships between vegetation reflectance (indicative of vegetation functioning), plant light use efficiency (Rue) and coincident measurements of carbon and water fluxes. Our approach focuses on the determination and monitoring of Rue using the remote sensing derived photochemical reflectance index (PRI, (based on canopy reflectance at 531 and 570 nm) and other spectral indices. Modeling Rue at the canopy scale is not straightforward, as PRI is a function of both directional reflectance and plant physiological status. To address these complexities, we have designed and built an innovative, tower-mounted sensor (AMSPEC) which scans the top of the canopy to record changes, every 15 seconds, in leaf functioning.