Spatiotemporal Dynamics of Bedload Sediment Flux in Large Rivers

摘要本研究项目将为全球尺度的大河泥沙通量预测和分析提供新的知识，并特别关注河床泥沙的输送。研究人员将开发一个全球分布的河床通量计算机模型，以分析河床与环境动力学之间的空间相互作用，以及悬浮输送的河床与泥沙之间的比例。该项目将为河流地貌的驱动因素和机制提供新的见解，从而改变有关这些关键地貌过程的基本分析能力。该项目将包括一个多方面的教育计划，通过研究、指导和涉及研究生、本科生、中学生以及公众的外展活动相结合，促进地理和地球科学的研究、教学和学生参与。项目成果将通过在阿拉巴马州自然历史博物馆举办的长期解释性展览，提高公众对水资源和教育的认识。河床输沙是河流系统物理、生物和化学动力学的重要驱动因素，它影响河流系统的水质和可用性、河流形态和生态功能以及海岸动态。研究者将在现有的全球尺度水文模型框架内开发一个新的河床通量模块。分析将侧重于大规模模拟中基于物理的床沙模型的普遍适用性，以及沿水系悬浮通量与床沙通量之比的空间趋势及其与流域特征的关系。为了促进这些分析并验证模型，将从现有的美国地质调查局数据库、学术文献、在线资源和研究者的合作网络中收集一个全球分布的观测数据库。这项研究的结果将提供第一个在空间和时间上明确的全球河床通量的一阶估计，并为研究全球大型河流的河床通量的参数、驱动因素和机制提供一个数值框架。河流中沉积物运输的量化将对研究碳和营养循环、河流、沿海和海洋生态、大坝可持续性以及水和粮食安全具有催化作用。

NATIONAL SCIENCE FOUNDATIONGEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAMABSTRACTThis research project will provide new knowledge regarding global-scale predictions and analysis of sediment fluxes in large rivers, with special attention given to sediment transported in riverbeds. The investigator will develop a globally distributed, bedload-flux computer model to analyze the spatial interactions between bedload and environmental dynamics as well as the ratio between bedload and sediment transported in suspension. The project will provide new insights into the drivers and mechanisms of fluvial geomorphology, thereby transforming fundamental analytical capabilities with regard to these key geomorphological processes. The project will incorporate a multifaceted educational plan that promotes research, teaching, and participation of students in geography and the geosciences through a combination of research, mentoring, and outreach activities involving graduate, undergraduate, and middle school students as well as the general public. Project results will enhance public awareness of water resources and education through a long-term interpretive exhibit at the Alabama Museum of Natural History. Bedload sediment transport is a significant driver of the physical, biological, and chemical dynamics in river systems, and it affects water quality and availability in river systems, river shape and ecological functioning, and coastal dynamics. The investigator will develop a new bedload flux module within an existing global-scale hydrological modeling framework. The analyses will focus on the universal applicability of the physically based bedload module for large-scale simulations and on the spatial trends of the ratio between suspended and bedload fluxes along river systems as well as its relationship to river basin characteristics. To facilitate these analyses and to validate the model, a globally distributed observational database will be collected from existing U.S. Geological Survey databases, scholarly literature, online resources, and the investigator's collaborative network. Outcomes from this research will provide one of the first spatially and temporally explicit first-order estimates of global bedload flux and a numerical framework for studying the parameters, drivers, and mechanisms of bedload flux in large global rivers. The quantification of sediment transport in rivers will be catalytic for examining carbon and nutrient cycles, river, coastal and marine ecology, dam sustainability, and water and food security.