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

植物光合作用监测是了解陆地碳循环的关键组成部分，需要对植被覆盖的陆地表面有详细的了解。遥感是以空间连续的方式观察植被特征的理想技术，然而，植被生长在空间和时间上的变化需要关于土壤水分、养分状况和气候的更多信息。这项研究计划将建立植被反射率(指示植被功能)、植物光能利用效率(RUE)以及碳和水通量的一致测量之间的函数关系。我们的方法侧重于使用遥感得出的光化学反射指数(PRI)(基于531和570 nm的冠层反射率)和其他光谱指数来确定和监测RUE。在冠层尺度上模拟RUE并非易事，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，我们设计并制造了一种创新的塔式传感器(AmSpec)，它可以扫描树冠顶部，每隔15秒记录树叶功能的变化。

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.