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。从最小的沙洲向下游移动，到大洪水后河道的大规模改道，流动的形式和规模各不相同。目前尚不清楚这些多尺度的河流流动是如何对持续的气候变化和人类活动（如水坝、森林砍伐）做出反应的，这些活动正在严重破坏全球河流的水和沉积物供应。这组研究人员将利用最先进的图像处理技术，在卫星档案（近半个世纪的全球图像）中调查多尺度河流的流动性，以解决这一知识鸿沟。本项目将提供本科生、研究生1名、博士后1名的跨学科培训机会。它还将与现有项目合作，向代表性不足的群体提供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未来的河流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，将使用粒子图像测速法捕获单个河岸和酒吧的较小尺度运动。其次，河道改道、洪泛区改造和其他过程的大尺度运动将使用基于达尺度像素的方法来捕获。然后，研究人员将河流流动性结果与全球观测结果以及泥沙和水供应模型相结合，以验证两个具体假设：1)大尺度河流流动性的速度是由长期的水和沙供应决定的；2)小规模河岸移动的速度已经发生了变化，以响应最近气候和人为引起的水和沉积物供应中断，并有一定程度的自然变化，这取决于河流类型（如蜿蜒，辫状）。这项工作将提高我们对全球河流流动性的理解和比较分析能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.