EAR-Climate: Global Survey of Multiscale River Mobility and its Response to Climate Change and Human Interference

河流天生就是流动的。流动性有各种形式和大小，从最小的沙洲向下游进军，到大洪水后大规模改道河道。目前尚不清楚这些河流流动的多个尺度如何应对持续的气候变化和人类活动(例如，大坝、砍伐森林)，这些活动正在极大地扰乱向世界各地河流供应的水和泥沙。这组调查人员将通过使用最先进的图像处理技术，在卫星档案中调查近半个世纪的全球图像中的多尺度河流流动性，来解决这一知识差距。该项目将为本科生、一名研究生和一名博士后研究员提供跨学科培训的机会。它还将与现有项目合作，向代表不足的群体提供K-12外展服务，并提供有价值的公共数据集，为我们不断变化的世界中河流沿线的未来研究和管理提供信息。为了调查多尺度河流的流动性，调查人员将利用两种最先进的图像处理技术。首先，使用粒子图像测速技术捕捉单个堤坝的较小尺度运动。其次，将使用基于REACH尺度的像素方法来捕捉河道改道、滩地改造和其他过程的更大尺度的运动。然后，研究人员将把河流流动结果与全球观测和泥沙和供水模型结合起来，以检验两个具体的假设：1)大规模河流流动的速度是由水和泥沙的长期供应决定的；以及2)小规模河岸运动的速度已经改变，以应对最近气候和人为造成的水和泥沙供应中断，一定程度的自然变异性取决于河流类型(例如，曲折和辫状)。这项工作将促进我们对全球河流流动性的比较分析的理解和能力。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Rivers are inherently mobile. Mobility comes in all shapes and sizes, from the downstream march of the smallest sandbar to the wholesale diversion of river channels after a major flood. It remains unclear how these multiple scales of river mobility are responding to ongoing climate change and human activities (e.g., dams, deforestation), which are drastically disrupting the water and sediment supplied to rivers worldwide. This team of investigators will tackle this knowledge gap by surveying multiscale river mobility in the satellite archive—nearly a half-century of global imagery—using state-of-the-art image processing. The project will provide opportunities for interdisciplinary training to undergraduate students, one graduate student, and one postdoctoral researcher. It will also provide K-12 outreach to underrepresented groups in partnership with existing programs, and deliver a valuable public dataset to inform future studies and management along rivers in our changing world.To survey multiscale river mobility, investigators will leverage two state-of-the-art image-processing techniques. First, the smaller-scale motion of individual banks and bars will be captured using particle image velocimetry. Second, the larger-scale motion of channel diversions, floodplain reworking, and other processes will be captured using reach-scale pixel-based methods. Then, investigators will couple river mobility results with global observations and models of sediment and water supply to test two specific hypotheses: 1) the pace of large-scale river mobility is set by the long-term supply of water and sediment; and 2) the pace of small-scale bank movements has changed in response to recent climate- and human-induced disruption in water and sediment supply, with some degree of natural variability that depends on river type (e.g., meandering, braided). This work will advance our understanding and ability to comparatively analyze river mobility across the globe.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.