Collaborative Research: Lagrangian transport and patchiness of buoyant material in estuarine systems

合作研究：河口系统中浮力物质的拉格朗日输送和斑块性

基本信息

批准号：
2148370
负责人：
Tobias Kukulka
金额：
$ 57.46万
依托单位：
University of Delaware
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2025-02-28
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2148370&HistoricalAwards=false
关键词：
Collaborative Research Lagrangian transport patchiness

项目摘要

Understanding processes that transport material in estuarine systems is central to fundamental studies of estuarine physics as well as to management practices in these socioeconomically important and highly anthropogenically impacted systems. Buoyant material, such as floating debris, marine organisms, oil and microplastics may be aggregated and trapped within estuaries or dispersed and discharged to the coastal ocean by these transport processes. Strong convergent surface flows across the estuary organize buoyant material into laterally narrow near-surface patches that may extend up to a few kilometers along the estuary. Local currents that move these patches may substantially differ from tidally and laterally averaged currents, which are often used to estimate estuarine transport characteristics. A major objective of this project is to contrast the transport of material in a frame work that follows the flow, known as the Lagrangian framework, with one based on a fixed point reference frame, or the Eulerian framework. Often the Lagrangian trajectories of material differ from those inferred from the Eulerian mean flows. The classic example stems from surface waves where the average velocity at a point (Eulerian) will be zero but a particle oscillating with the wave included flow will have an average velocity in the direction of wave propagation, due to the Stokes drift or Stokes velocity. This project will investigate the importance of Stokes transport in estuaries. The project research hypotheses are: (1) Stokes transport associated with amplitude and phase structure of tidal flows contribute significantly to the transport of buoyant material in both the along-channel and cross- channel directions. (2) Buoyant material organizes in surface patches due to the lateral estuarine circulations. (3) Patches of buoyant material are fundamentally transported by spatiotemporally localized currents that vary substantially across the estuary. (4) The observed spatiotemporal distributions of marine debris in Delaware Bay are a characteristic signature of Lagrangian estuarine transport. The project will use both modeling and observations to address transport of buoyant material in estuaries. This research will help solve practical real world problems related to marine pollution, gas exchange and fisheries. The PIs have close working relationships with resource managers and policy makers with whom they will communicate relevant new understanding. The project will train graduate and undergraduate students, and both PIs and students will participate in public outreach events. This project will examine transport of buoyant material in estuaries, specifically the Delaware Estuary, including its aggregation within estuaries, and the effects of resulting patchiness of buoyant material on its transport through the estuary. The hypotheses will be addressed through an integrated research program that employs original concept models as well as observations and simulations. Research objectives include: (1) Assess and advance idealized linear and weakly-nonlinear models of the three-dimensional estuarine circulations to determine key factors that control secondary circulations, such as bathymetry, tides, Coriolis force, and baroclinicity. (2) Develop and evaluate a Lagrangian framework for the estuarine circulation based on the integration of the idealized models with existing field observations and an asymptotic Stokes drift analysis to contrast fundamental differences between the Eulerian and Lagrangian approaches. (3) Conduct and integrate hydrodynamic simulations and field observations of the Delaware Estuary to understand tidal neap-spring and high-low river discharge variability. (4) Apply the Lagrangian framework to simulation and observation results, as well as recent marine debris observations, to reveal principal Lagrangian transport characteristics and improved estuarine transport estimates. By exploring and developing a Lagrangian framework this project would fundamentally advance our understanding of the physics of estuarine transport processes. This work will transform the current paradigm of estuarine material transport to include new lateral transport processes, thereby advancing the current conceptual understanding of buoyant tracer dynamics in an estuary, and will contribute to solving practical real world problems.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.

了解河口系统中运输材料的过程对于河口物理学的基本研究以及这些社会经济重要且对人为高度影响的系统的管理实践至关重要。浮动物质，例如浮动碎屑，海洋生物，石油和微塑料，可能会聚集并捕获在河口中，或通过这些运输过程分散并分散并排放到沿海海洋中。强烈的收敛表面流过河口，将浮力材料组织到侧面狭窄的近表面斑块中，沿河口延伸至几公里。移动这些斑块的局部电流可能与潮汐和侧向平均电流有很大不同，这些电流通常用于估计河口传输特征。该项目的一个主要目的是将材料在遵循流动的框架工作中的运输（称为拉格朗日框架）与基于固定点参考框架或欧拉框架的框架进行对比。通常，材料的拉格朗日轨迹与欧拉均值流的推论的轨迹不同。经典的例子源自表面波，其中一个点（欧拉尔）的平均速度为零，但由于stokes漂移或stokes速度，随着波浪流动的粒子振荡将在波传播方向上具有平均速度。该项目将调查Stokes运输在河口中的重要性。项目研究假设是：（1）与潮流的幅度和相结构相关的Stokes转运，在沿渠道和跨通道方向上均有助于浮力物质的运输。（2）由于河口外侧循环，浮力物质在表面斑块中组织。（3）浮力材料的斑块从根本上是由河口在河口大大差异的时空定位电流运输的。（4）特拉华湾海洋碎片的时空时空分布是拉格朗日河口运输的特征标志。该项目将同时使用建模和观察结果来解决河口中浮力材料的运输。这项研究将有助于解决与海洋污染，天然气交换和渔业有关的实际现实世界问题。 PI与资源经理和政策制定者有着密切的工作关系，他们将与他们传达相关的新理解。该项目将培训毕业生和本科生，PIS和学生都将参加公共外展活动。该项目将检查河口中浮力物质的运输，特别是特拉华州的河口，包括其在河口中的聚集，以及产生浮力材料在其通过河口的运输过程中产生的影响。假设将通过采用原始概念模型以及观察和模拟的综合研究计划来解决。研究目标包括：（1）评估和推进三维雌激素循环的理想化的线性和弱非线性模型，以确定控制二次循环的关键因素，例如测深，潮汐，潮汐，科里奥利力和横向线性性。（2）基于理想化模型与现有现场观测值的整合以及渐近的Stokes漂移分析，开发和评估河口循环的拉格朗日框架，以对比欧拉和拉格朗日方法之间的基本差异。（3）进行和整合特拉华河口的流体动力模拟和现场观察，以了解潮汐neap-spring和高低河流排放的变异性。（4）将拉格朗日框架应用于模拟和观察结果以及最近的海洋碎片观测，以揭示主要的拉格朗日运输特征和改善的河口运输估计。通过探索和开发拉格朗日框架，该项目从根本上可以提高我们对河口运输过程物理学的理解。这项工作将改变河口材料运输的当前范式，包括新的横向运输过程，从而在河口中进步对浮力示踪动力的当前概念理解，并将为解决实用的现实世界问题做出贡献。该奖项反映了NSF的立法使命，并通过使用基金会的智力效果和广泛的评估来评估支持NSF的立法任务。