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

激流是一种危险的海滩危险因素。激流是一种狭窄的、朝向近海的强流。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之间交换沉积物、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。由于它们的间歇性，瞬时撕裂流特别难以观察，我们对驱动、维持和确定其近海范围的过程的了解也是有限的。在这个项目中，这位研究员的目标是量化近岸系统之间的瞬时撕裂流交换。结果可能为休闲海滩游人的安全提供有价值的信息，并增进对沿海生态系统材料运输和健康的了解。为了扩大对海洋科学的参与，这位研究员将指导一名暑期本科生实习生使用数值海洋模型。这位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，最终将举办一个以职业为导向的研讨会，即冲浪科学青少年会议。冲浪区和内大陆架之间的过渡涉及到跨动力区域的过渡。虽然波浪破碎主导了冲浪区内的环流强迫，但内陆架受到包括波浪浅滩、浮力和地球-S自转在内的多种力的综合作用。在近岸均匀的海滩上，瞬时激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，使用波分辨Boussinesq模型，该研究员的目的是更好地理解瞬时撕裂电流驱动的交换。为了实现这一目标，该研究员将在一个广泛的参数空间内进行一系列模拟，包括正常和倾斜入射海浪条件以及多个海滩斜坡。将跟踪近岸涡旋，以分析其动力学，并量化瞬时撕裂流的强度和离岸范围。将确定激流特征、其散体交换以及入射海浪和海滩条件阵列之间的预测关系。这些特征可以与其他沿海交换过程进行比较，如风、斯托克斯？漂移和内部波浪驱动的传输。瞬时激流交换发生在小尺度上，海岸环流模型通常无法解决这一问题。这项工作也将有助于在这样的模型中实现瞬时撕裂电流行为的参数化。

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.