EAR-PF: The impact of varying sediment supply on Arctic delta-front transport processes

EAR-PF：不同沉积物供应对北极三角洲前缘输送过程的影响

• 批准号: 1952815
• 负责人: Brandee Carlson
• 金额: $ 17.4万
• 依托单位: Carlson, Brandee Nicole
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952815&HistoricalAwards=false
• 关键词: EAR; PF; impact; varying; sediment

An NSF EAR Postdoctoral Fellowship has been awarded to Dr. Brandee N. Carlson to carry out research and education activities under the mentorship of Dr. Irina Overeem at the University of Colorado, Boulder. The project seeks to assess how enhanced sediment supply from melting ice sheets and glaciers, and thawing permafrost impacts the growth of Arctic deltas. The sand delivered to Arctic deltas, particularly those in West Greenland, is recognized as a potential resource for coastal restoration efforts and for industrial use (primarily concrete production) worldwide. This project will investigate the processes that control sediment retention along Arctic coastlines using field observations and remote sensing. This work will inform policy and economic decisions for sand-use in Greenland. Furthermore, the information gained from this project will be used to develop a learning module geared toward introductory undergraduate students that allows the user to explore controls on delta growth. The model will be housed at SedEdu, which is a suite of educational tools related to geomorphology and sedimentology.Subaqueous delta-front sediment transport processes are an important control on coastal evolution. Rivers and subaqueous density flows are the largest mechanisms for sediment redistribution on Earth's surface. Subaerial coastal evolution is easily-observable through historical and satellite imagery, however quantifying subaqueous sediment movement is inherently difficult because it typically requires observation in the field. Delta-front sediment transport processes become especially important to consider for rapidly growing deltas with high sedimentation rates. Under warming climate conditions, Arctic deltas, particularly those in Greenland, are rapidly growing as they receive enhanced sediment supply from melting and retreating glaciers and thawing permafrost. While there is evidence for delta-front failures that transport substantial volumes of sediment, it is unclear to what degree they influence delta progradation rates and sediment retention along coastlines. This study links readily observable data (images of subaerial delta activity) to subaqueous sediment transport processes. The objectives of this study are to determine how subaerial delta activity links to sediment transport at the subaqueous delta front and how enhanced sediment supply impacts marine sediment transport processes on Arctic deltas. In turn, the influence of delta-front failures on delta topset dynamics will be evaluated. These questions will be addressed over different temporal and spatial scales. Dr. Carlson will evaluate individual delta-front transport events at one field location during variable discharge conditions, using repeat bathymetric data. During this field campaign, changes in the subaerial delta topset (e.g. wetted area) will be evaluated using satellite imagery. Correlations between delta topset activity and delta-front transport timing/location will be used to infer relationships under past conditions (evaluated using 34 years of Landsat data) and to consider delta-front sediment transport under future conditions (e.g. how do Arctic delta-front failures vary under higher water and sediment discharge conditions in a waring climate?). These findings may offer insight into the conditions and potential effects of shifting sediment delivery for other fjord deltas in Greenland. The Geomorphology and Land-use Dynamics program in the Earth science division is co-funding this fellowship.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.

NSF EAR博士后奖学金已授予Brandee N. Carlson博士，以在科罗拉多大学博尔德分校的Irina Overeem博士的指导下进行研究和教育活动。该项目旨在评估融化冰盖和冰川融化的沉积物供应如何增强，以及融化的多年冻土影响北极三角洲的生长。向北极三角洲，特别是西格陵兰的三角洲的沙子被认为是沿海恢复工作和工业用途（主要是混凝土生产）的潜在资源。该项目将使用现场观测和遥感来调查控制北极海岸线的沉积物保留的过程。这项工作将为格陵兰岛的沙使用政策和经济决策提供依据。此外，从该项目中获得的信息将用于开发一个针对入门本科生的学习模块，该模块允许用户探索对DELTA增长的控制。该模型将安置在Sededu，这是一套与地貌学和沉积学有关的教育工具。SubaqueousDelta-Front Sediment Transpertes是对沿海进化的重要控制。河流和水下密度流是地球表面沉积物重新分布的最大机制。通过历史图像和卫星图像，沿海沿海的进化很容易被观察，但是量化的亚水沉积物运动本质上是困难的，因为它通常需要在田间观察。对于迅速增长的较高沉积速率的三角洲，三角洲往前的沉积物运输过程尤为重要。在温暖的气候条件下，北极三角洲，尤其是格陵兰岛的三角洲，随着它们从融化和撤退冰川和融化的多年冻土而获得的沉积物供应增强，它们正在迅速生长。虽然有证据表明，三角洲前的失败会带来大量沉积物，但尚不清楚它们在多大程度上影响三角洲的前列率和沿海地线的沉积物保留。这项研究将易于观察到的数据（海底三角洲活性图像）与水下沉积物传输过程联系起来。这项研究的目的是确定小英次三角洲的活性如何与水下三角洲前沿的沉积物传输联系在一起，以及增强的沉积物供应如何影响北极三角洲的海洋沉积物传输过程。反过来，将评估三角洲 - 前失败对三角洲顶盘动力学的影响。这些问题将在不同的时间和空间尺度上解决。 Carlson博士将使用重复的测深数据在可变的排放条件下在一个野外地点评估单个三角洲的运输事件。在此现场活动期间，将使用卫星图像评估小英里底三角洲顶部（例如湿区）的变化。 Delta Topset活动与三角前运输时机/位置之间的相关性将用于推断过去条件下的关系（使用34年的Landsat数据评估），并考虑在未来条件下（例如，在战争气候下的水和沉积物排放条件下，在北极三角洲 - 弗里特在更高的水和沉积物条件下如何在北极三角洲发生下降？）。这些发现可能会深入了解格陵兰岛其他峡湾三角洲的沉积物递送的状况和潜在影响。地球科学部的地貌和土地利用动态计划正在共同资助这一奖学金。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准来通过评估来获得支持的。