Doctoral Dissertation Research: Roles of Tributaries, Floodplains, and the Anabranching Channels on Suspended Sediment Transport Patterns

摘要大河在侵蚀物质的运输、生物地球化学循环、复杂生态系统的维持、环境的生物多样性以及为人类提供各种社会经济服务等方面发挥着重要作用。尽管它们具有自然和经济上的重要性，但由于这些过程的物理和机械复杂性，对大型河流过程进行更全面的了解一直很困难。本博士论文研究项目将采用创新的方法，包括将遥感数据与水文地貌数据相结合，以推进对大型河流相关复杂河流环境中沉积物分布模式的基本认识。该项目将通过表征沉积物运移的时空格局和识别河道洪泛平原系统中的水沉积相互作用，为大型河流的形态动力学提供新的见解。项目成果将有助于解决广泛的水资源管理问题、湿地保护生态问题和地方决策问题。该项目还将加强美国和巴西大学和科学中心之间的机构联系，并将向美国当地学校提供教育推广，以支持代表性不足的K-12科学学生。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。由于沉积物在任何河道-洪泛平原系统的水物理、生态和生物地球化学功能中起着重要作用，因此，在多时间尺度上对沉积物运输的评估和沉积环境的测绘一直是河流科学家关注的重点领域。获得本奖项的博士学位论文研究将围绕以下两个核心问题展开：(1)主河道支流主要汇合处泥沙运移的时空格局是什么？(2)洪泛平原的输沙、沉积模式和泥沙收支是什么？学生将通过在亚马逊河沿岸的几个地点进行实地调查、地貌测绘和现场样本收集来回答这些问题。他将把这些野外数据与遥感衍生产品结合起来，模拟和表征河流河道-洪泛平原系统的宏观泥沙输送机制。该研究项目的成果将有助于全球对河流分支模式的理解，并为世界各地大型河流系统的形态动力学和环境机制提供新的线索。

NATIONAL SCIENCE FOUNDATIONGEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAMABSTRACTLarge rivers play an important role in the transport of eroded materials, biogeochemical cycles, sustenance of complex ecosystems, biodiversity of their environments, and providing a variety of socio-economic services for humans. Despite their natural and economic importance, developing a fuller understanding of large river processes has been difficult because of the physical and mechanistic complexities of such processes. This doctoral dissertation research project will use innovative methods that include the integration of remotely sensed data with hydrogeomorphologic data to advance basic understanding of sediment distribution patterns in the complex fluvial environments associated with large rivers. The project will provide new insights into the morphodynamics of large rivers by characterizing the spatiotemporal patterns of sediment transport and identifying the hydrosedimentary interactions in channel floodplain systems. Project results will be useful for addressing a broad range of water resources management issues, wetlands preservation ecology problems, and local policy-making questions. The project also will strengthen institutional ties between U.S. and Brazilian universities and scientific centers, and it will incorporate educational outreach to local U.S. schools for support of underrepresented K-12 students in the science. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.Because sediment plays a major role in the hydrophysical, ecological, and biogeochemical functions of any channel-floodplain system, the assessment of sediment transport and mapping of sedimentary environments over multi-temporal scales have been areas of focus for river scientists across multiple disciplines. The doctoral student whose dissertation research will be supported by this award will focus on two core questions: (1) What are the spatiotemporal patterns of sediment transport at major confluences along an anabranching main river channel? (2) What are the sediment transport, deposition patterns, and sediment budgets in the floodplains? The student will answer these questions by conducting field surveys, geomorphic mapping, and in-situ sample collection at several sites along the Amazon River. He will integrate these field data with remote sensing-derived products to model and characterize the macroscale sediment transport mechanisms in the channel-floodplain systems of the river. Outcomes from this research project would be useful to a global understanding of riverine anabranching patterns as well as shedding new light on the morphodynamics and environmental mechanisms of large river systems around the world.