Exchange Between the Surfzone and Inner Shelf: The Contribution of Transient Rip Currents

表面带和内陆架之间的交换：瞬态离岸流的贡献

• 批准号: 1521653
• 金额: $ 17.4万
• 依托单位: Suanda Sutara H
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1521653&HistoricalAwards=false
• 关键词: Exchange; Between; Surfzone; Inner; Shelf

Rip currents - narrow jets of strong, offshore-directed flow - are a dangerous beach hazard. They account for the majority of the U.S. life guard rescue effort and potentially play a role in many coastal processes by exchanging material such as sediments, pollutants, and intertidal invertebrates across nearshore ocean systems. Because of their episodic nature, transient rip currents are particularly challenging to observe and our understanding of the processes that drive, sustain, and determine their offshore extent is limited. In this project, the fellow aims to quantify transient rip current exchange across nearshore systems. Results may provide valuable information for the safety of recreational beach goers and improve understanding on the transport of materials across and health of our coastal ecosystems. To broaden participation in marine science, the fellow will mentor a summer undergraduate intern on the use of numerical ocean models. The fellow will also work with a local high school to develop and deliver a marine science curriculum culminating with a career-oriented workshop, the Surf Science Teen Conference. The transition between the surfzone and the inner continental shelf involves a transition across dynamical regions. While wave breaking dominates the forcing of circulation within the surfzone, the inner shelf is subject to a combination of forces including wave shoaling, buoyancy, and the earth?s rotation. On alongshore-uniform beaches, transient rip currents are potentially the dominant mechanism driving the exchange of material across these regions. In this project, using a wave-resolving Boussinesq model, the fellow aims to develop a better understanding of transient rip current driven exchange. To accomplish this aim, the fellow will conduct a series of simulations over a wide parameter space including both normally and obliquely incident wave conditions and multiple beach slopes. Nearshore vortices will be tracked to analyze their dynamics and quantify the strength as well as offshore extent of transient rip currents. Predictive relationships will be determined between rip current characteristics, their bulk exchange, and the array of incident wave and beach conditions. These characteristics can then be compared to other coastal exchange processes such as wind, Stokes? drift, and internal wave-driven transports. Transient rip current exchange occurs over small scales generally unresolved by coastal circulation models. This work will also contribute towards the parameterization of transient rip current behavior in such models.

撕裂流--强烈的、指向离岸的狭窄射流--是一种危险的海滩危险。它们占美国救生员救援工作的大部分，并可能通过在近岸海洋系统中交换沉积物、污染物和潮间带无脊椎动物等物质，在许多沿海过程中发挥作用。由于其情节的性质，瞬态裂流是特别具有挑战性的观察和我们的理解，驱动，维持和确定其离岸范围的过程是有限的。在这个项目中，该研究员的目的是量化近岸系统的瞬时裂流交换。研究结果可能为休闲海滩游客的安全提供有价值的信息，并提高对材料运输和沿海生态系统健康的理解。为了扩大对海洋科学的参与，该研究员将指导一名暑期本科实习生使用数值海洋模型。该研究员还将与当地一所高中合作，开发和提供海洋科学课程，最终举办面向职业的研讨会，即冲浪科学青少年会议。冲浪带和内大陆架之间的过渡涉及到跨越动力区的过渡。虽然波浪破碎占主导地位的强迫内surfzone环流，内架是受一个组合的力量，包括波浪浅滩，浮力，和地球？s旋转。在沿岸均匀的海滩上，瞬时离岸流可能是推动这些地区物质交换的主要机制。在这个项目中，使用波解析Boussinesq模型，研究员的目的是发展一个更好的理解瞬态撕裂电流驱动的交换。为了实现这一目标，该研究员将进行一系列的模拟在一个广泛的参数空间，包括正常和斜入射波条件和多个海滩斜坡。近岸涡将被跟踪，以分析其动力学和量化的强度，以及瞬态裂流离岸范围。将确定裂流特征、其体积交换以及入射波和海滩条件的排列之间的预测关系。然后可以将这些特征与其他沿海交换过程进行比较，例如风、斯托克斯？漂移和内部波浪驱动的运输。瞬时裂流交换发生在小尺度上，通常无法由沿海环流模型解决。这项工作也将有助于对参数化的瞬态ripcurrent行为在这种模式。