Postdoctoral Fellowship: EAR-PF: Linking the past to the future: Using PETM fluvial records to understand the effects of climate change on rivers

Bolton Howes博士被授予NSF地球科学博士后奖学金，在华盛顿大学的Akshay Mehra博士和西部华盛顿大学的Brady Foreman博士的指导下开展研究和专业发展活动。从为农业提供灌溉和营养，到充当连接内陆地区与沿海、河流和泛滥平原的运输路线，对人类和我们的星球的运转至关重要。河流和洪泛平原对气候、植被覆盖和土地利用的变化也非常敏感。由于河流可能通过洪水和河道的移动对城市、农业和基础设施构成风险，因此了解河流系统将如何应对持续的气候变化至关重要。为了寻找河流未来的线索，地质学家可以求助于沉积记录。古新世-始新世最高温度(PETM)代表了地球过去快速变暖的重要时期，类似于目前的气候变化。科学家们知道，PETM引发的环境变化影响了沉积物模式和河流行为。例如，研究表明，在PETM期间，几个位置的通道运动增加。现代河流流动性的增加可能会导致基础设施遭到破坏，水资源供应发生变化，航道发生变化。该项目有两个目标：(1)确定PETM期间河道运动的增加是某些流域特有的还是普遍现象，以及(2)利用卫星和调查的历史数据来确定人为气候变化是否导致现代河流的迁移率增加。该项目的发现将为人类如何更好地为下个世纪河流系统的预期变化做好准备提供宝贵的见解。该项目还将最终开发和传播用于三维建模的开放源码软件。本科生将成为研究的积极贡献者，学习野外地质学和地学定量方法的技能。最后，该项目将通过在实地博物馆的讲座促进公众参与。该项目采用双管齐下的方法来探索气候变化对河流景观行为的影响。首先，该项目将利用传统的地层学技术，结合无人机获取的数字高程模型和照片正射影像，测量Piceance、Hanna和Bighorn盆地PETM之前、期间和之后河流砂岩的形态和大小。由无人机图像创建的三维模型将有助于更准确地测量古代河流的几何形状，并改进对不确定性和横向变异性的估计。这些测量将使该项目能够准确地描述PETM期间温度升高和季节性增加所引起的河流动力学变化。其次，该项目将使用来自卫星图像、地图和调查的现代河流的历史记录，以确定人为气候变化和土地利用的变化是否影响了现代河流的行为。这项对现代河流的分析将确定现代河流是否已经适应了不断变化的气候，或者是否(以及需要多少)基础设施计划来适应河流景观行为的未来变化。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。

Dr. Bolton Howes has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities under the mentorship of Dr. Akshay Mehra at the University of Washington and Dr. Brady Foreman at Western Washington University. From providing irrigation and nourishment for agriculture to acting as transport routes that connect inland areas to the coasts, rivers and floodplains are critical to the functioning of humanity and our planet. Rivers and floodplains also are highly sensitive to changes in climate, vegetation cover, and land use. Since rivers can pose risks to cities, agriculture, and infrastructure through flooding and the movement of channels, it is crucial to understand how river systems will respond to ongoing climate change. For clues about the future of rivers, geologists can turn to the sedimentary record. The Paleocene-Eocene Thermal Maximum (PETM) represents a significant period of rapid warming in our planet's past, analogous to the current climatic changes. Scientists know that the environmental changes triggered by the PETM affected sediment patterns and river behavior. For instance, research indicates an increase in channel movement at several locations during the PETM. Increased mobility in modern rivers could lead to infrastructure damage, alterations in water availability, and shifts in navigational routes. This project has two objectives: (1) to determine if the increased channel movement during the PETM was specific to certain basins or a widespread phenomenon, and (2) to use historical data from satellites and surveys to ascertain if anthropogenic climate change has led to increased migration rates of modern rivers. The findings of this project will provide valuable insights into how humanity can better prepare for anticipated changes in river systems over the coming century. This project will also culminate in the development and dissemination of open-source software for 3D modeling. Undergraduate students will be active contributors to the research, learning skills in field geology and quantitative methods for the geosciences. Finally, the project will foster public engagement through lectures at museums within the field area.This project employs a two-pronged approach to explore the impacts of climate change on the behavior of fluvial landscapes. First, the project will utilize traditional stratigraphic techniques in conjunction with drone-derived digital elevation models and photo-orthomosaics to measure the morphology and size of fluvial sandstones before, during and after the PETM in the Piceance, Hanna, and Bighorn Basins. Three-dimensional models, created from drone imagery, will facilitate more accurate measurements of ancient rivers geometry and improve the estimation of uncertainty and lateral variability. These measurements will enable the project to accurately characterize the changing fluvial dynamics induced by the heightened temperatures and increased seasonality during the PETM. Secondly, the project will employ historical records of modern rivers, sourced from satellite imagery, maps, and surveys, to ascertain if anthropogenic climate change and alterations in land use have influenced modern river behavior. This analysis of modern rivers will determine if modern rivers have already adjusted to the changing climate, or if (and how much) infrastructure plans need to accommodate future change in fluvial landscape behavior.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.