RAPID: Mapping drought stress and hydraulic refugia with repeat hyperspectral data

日益严重的干旱伴随着与气候变化有关的热浪正在危害全球生态系统和经济。该项目利用美国航天局制作的独特的遥感图像时间序列和加州南部正在发生的干旱，开发绘制和监测植物干旱胁迫的新技术。对植物干旱胁迫、植物用水和植物水源（例如表层土壤或地下水）的详细测量将与对植物含水量的遥感测量相联系，以制定对干旱胁迫进行遥感监测的方法。这些方法将用于确定在持续干旱期间地貌上具有抗旱能力和易受干旱影响的地区，并将利用不久的将来发射的卫星为农业、林业和水资源管理促进全球干旱监测。该项目还将培训研究生和本科生，并为圣巴巴拉的加州大学新的实地本科课程奠定基础。该项目旨在以前所未有的空间和时间粒度来了解干旱胁迫的空间变化。该项目利用了2022年3月至6月美国宇航局表面生物学和地质学高频时间序列探路者使命的独特重复机载高光谱图像，恰逢加州南部持续的长期干旱。拟议的研究框架将解决一些关键的悬而未决的问题，围绕干旱引起的树木死亡率，地下水的访问，并在一个物种内的抗压力的变化。详细的生理测量两个物种的橡树在地形和土壤梯度的水的可用性将被链接到植物冠层含水量和叶含水量的遥感指标，以遵循干旱胁迫的发展在整个景观的数千棵树在春季干旱。这将增加对水压力如何在空间上发展的理解，并确定地形-土壤脆弱地点和可能接触岩石水的水力避难所等景观特征。将地面生理压力测量与高时间分辨率的高光谱航空图像严格联系起来，将为了解地形、地貌和生态水文对植物干旱胁迫的控制提供工具，该奖项反映了NSF的法定使命，并通过使用基金会的知识产权进行评估，被认为值得支持。优点和更广泛的影响审查标准。

Increasing droughts accompanied by heat waves that are associated with climate change are harming ecosystems and economies worldwide. This project takes advantage of a unique time series of remote sensing images being produced by NASA and an ongoing drought in southern California to develop new techniques for mapping and monitoring plant drought stress. Detailed measurements of plant drought stress, plant water use and plant water source (e.g. surface soil or groundwater) will be linked to remotely sensed measurements of plant water content to develop methods for remotely monitoring drought stress. These methods will be used to identify areas of drought resilience and drought vulnerability on the landscape during the ongoing drought, and will facilitate global drought monitoring for agriculture, forestry and water resource management using satellites being launched in the near future. This project will also train graduate and undergraduate students and provide the foundation for new field-based undergraduate courses at the University of California, Santa Barbara. This project seeks to understand spatial variation in drought stress with unprecedented spatial and temporal granularity. The project takes advantage of unique repeat airborne hyperspectral imagery from the NASA Surface Biology and Geology High Frequency Timeseries Pathfinder mission March-June of 2022 that coincides with an ongoing prolonged drought in southern California. The proposed research framework will tackle some of the key outstanding questions surrounding drought-induced tree mortality, subsurface water access, and variations in stress resistance within a species. Detailed physiological measurements on two species of oak trees across topographic and edaphic gradients in water availability will be linked to remotely sensed metrics of plant canopy water content and leaf water content to follow the development of drought stress in thousands of trees across the landscape during the spring dry down. This will increase understanding of how water stress develops spatially and identify landscape features such as topo-edaphically vulnerable sites and hydraulic refugia that likely have access to rock water. Rigorously linking ground-based measurements of physiological stress to hyperspectral airborne imagery at high temporal resolutions will provide the tools to understand topographic, geomorphic, and ecohydrological controls on plant drought stress, and develop methods for global drought monitoring using upcoming hyperspectral satellite missions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.