Collaborative Research: Nonlinear Wake Observations at a Kuroshio Seamount (NOKS)

将分析2021-2022年期间在日本南部Tokara海峡平濑海山背风面收集的海洋学数据，以研究强非线性黑潮-海山相互作用和相关湍流。这些数据包括从船舶、系泊设备和剖面浮标阵列测量的温度、盐度、速度和湍流耗散的高分辨率观测。这些数据将用于确定动量和浮力方程中的主要非线性项，量化位涡异常，并确定造成海山下游20公里处高能湍流层的垂直和横向不稳定机制。阐明湍流生成机制，特别是在非线性尾流中，是改善现有湍流耗散和混合参数化的一项重要任务，因此对模拟和海洋中的能量级联、质量和营养物输送以及海洋地球化学收支具有广泛的意义。该项目将为早期职业科学家Anda Vladoiu博士提供支持。所有APL-UW PI都积极参与UW和当地科学中心以及西雅图K-12教室的外展活动。连战还积极支持西澳大学本科生的暑期项目。Kunze是西雅图太平洋科学中心的科学传播研究员，每年参与四次志愿者科学聚光灯活动，并参加一年一度的太平洋科学中心气候科学周末，介绍黑潮翻转环流和海洋湍流混合。黑潮和平濑海山之间的强烈相互作用产生了一个独特的非线性和湍流状态，可以在海洋之外进行研究。通常的线性内波和平衡动力学。将分析四维精细和微观结构调查，以研究Rossby数超过1和梯度Froude数为1/2（1）的强非线性黑潮-海山相互作用和相关湍流。𝑂船上ADCP、正在进行的CTD和正在进行的VMP辐射器调查，以及四个全深度EM-APEX浮箱阵列，提供了水平亚中尺度（~ 1 km）和垂直细尺度（~ 10 m）流动结构。两个ADCP/CTD系泊提供了6个月的背景流变率和剪切不稳定层的时间序列。这些数据将用于：㈠确定动量和浮力方程中的主要非线性项; ㈡量化位涡异常; ㈢确定造成海隆下游20公里处横扩散系数约为10−2 m2 s−1的高能湍流层的垂直和横向不稳定机制。𝐾 在海山背风面的六个月系泊时间序列将使亚惯性波动和内波波动分离，以解决可能的时空混淆问题。这将普遍提高对海洋中非线性流动-地形相互作用的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Oceanographic data collected in the lee of Hirase Seamount in Tokara Strait, south of Japan, during 2021-2022 will be analyzed to investigate strong nonlinear Kuroshio-seamount interactions and associated turbulence. The data include highly resolved observations of temperature, salinity, velocity, and turbulent dissipation measured from ship, moorings, and profiling float arrays. The data will be used to identify the dominant nonlinear terms in the momentum and buoyancy equations, quantify potential vorticity anomalies, and determine the vertical and lateral instability mechanisms responsible for energetic turbulence layers extending 20 km downstream of the seamount. Elucidating turbulence generation mechanisms, especially in nonlinear wakes, is an essential task to improve existing turbulent dissipation and mixing parameterizations, and therefore has broad implication for the energy cascade, mass and nutrient transports, and biogeochemical budgets in simulations and the ocean. This project will provide support for early-career scientist Dr. Anda Vladoiu. All APL-UW PIs are actively engaged in outreach at UW and local science centers and Seattle K-12 classrooms. Lien also actively supports the summer program for UW undergraduate students. Kunze is a Science Communication Fellow at the Pacific Science Center in Seattle, which involves four volunteer Science Spotlight activities per year, and participation in the annual Pacific Science Center-Climate Curiosity Weekend, to introduce the general public to the meridional overturning circulation and ocean turbulent mixing.Strong interactions between the Kuroshio and Hirase Seamount produce a uniquely nonlinear and turbulent regime that allows study outside the usual linear internal-wave and balanced dynamics. Four-dimensional fine- and microstructure surveys will be analyzed to investigate strong nonlinear Kuroshio-seamount interactions and associated turbulence where Rossby numbers exceed 1 and gradient Froude numbers are 𝑂(1). Shipboard ADCP, underway CTD and underway VMP radiator surveys, as well as four full-depth EM-APEX float box-arrays, provide horizontal submesoscale (~ 1 km) and vertical finescale (~ 10 m) flow structures. Two ADCP/CTD moorings provide 6-month time-series of the background flow variability and shear- unstable layers. These data will be used to (i) identify the dominant nonlinear terms in the momentum and buoyancy equations, (ii) quantify potential vorticity (PV) anomalies and (iii) determine the vertical and lateral instability mechanisms responsible for energetic turbulence layers with diapycnal diffusivities 𝐾 ∼ 10−2 m2 s−1 extending 20 km downstream of the seamount. The six-month long mooring time-series in the lee of the seamount will allow the separation of subinertial and internal-wave fluctuations to resolve possible time-space aliasing. These will generally improve understanding of nonlinear flow-topography interactions in the ocean.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.