Collaborative Research: The Role of Canyons in Boundary Mixing and Exchange with the Ocean Interior

合作研究：峡谷在与海洋内部边界混合和交换中的作用

• 批准号: 0728341
• 负责人: Erika McPhee-Shaw
• 金额: $ 18.61万
• 依托单位: San Jose State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0728341&HistoricalAwards=false
• 关键词: Collaborative; Research; Role; Canyons; Boundary

A field program is proposed to examine exchange of mixed boundary fluid with the stratified interior by measuring turbulence, internal waves and nepheloid layers in Monterey SubmarineCanyon and in several other canyons. Several questions will be addressed:1. What are the net effects of continental-slope internal-wave-driven boundary mixing on theinterior stratification of the ocean?2. Do finescale parameterizations for turbulent mixing fall short by a factor of 5 6 in canyons because of (i) a more coherent internal wave field than found in the open ocean or (ii) interactions with topography?Measurements will include full-depth velocity-temperature profile surveys with XCPs, time seriesof currents and water properties with transmissometer-equipped LADCP/CTD, time-series of turbulent mixing with a microstructure profiler, and a velocity and temperature profile time series of the bottom 120 m with a mooring equipped with ADCP and thermistor chain. These data will be used (i) to quantify the BBL energy budget by determining internal wave energy fluxes into and out of the boundary along with boundary-layer turbulent dissipation rates, and (ii) to characterize the distribution of nepheloid layers. Energy-flux divergence will be used to identify internal wave sources and sinks within the canyon while potential external sources will be identified from deep-water fluxes. In addition, new analysis techniques will be explored, including (i) the use of energy-flux co-spectra to diagnose internal wave reflection from the near-critical bottom slope, (ii) bi-coherence to evaluate relationships between high and low vertical wavenumbers, (iii) momentum-fluxes to evaluate bottom form drag, and (iv) stratification flux and sediment flux to determine the exchange of mixed boundary water with the stratified interior. This work is in collaboration with Eric Kunze at the University of Victoria, who will make the microstructure measurements and participate in analysis and interpretation of the whole data set. It will benefit from recent modeling efforts and measurements on the slope south of Monterey Bay during ONR's 2006 AESOP program.Intellectual Merit: We are motivated by fundamental questions concerning (i) the exchange of fluid mixed on the boundary with that in the stratified interior and its role in global mixing and the thermohaline circulation, and (ii) how to better parameterize internal-wave-driven turbulent mixing near topography. The survey plan combines spatial coverage and high-frequency timeseries to allow rigorous testing of significance. The core XCP pattern spanning a full cycle of the semidiurnal tide will provide better resolution of a coherent internal wavefield in space and time than hitherto achieved outside the laboratory in order to better understand the cascade of energy through the internal wave field near sloping topography. In addition, exploratory measurements in other continental slope canyons will aid in expanding applicability to a global scope.Broader Impacts: The multi-institutional collaboration will advance interdisciplinary understanding of mixing processes in Monterey Canyon and other continental slope canyons, an important facet for local budgets of nutrients, sediment, and chemical tracers. Through the refinement of finescale mixing parameterizations, it will also aid large-scale mixing budgets and,potentially, climate model predictions. Education will be advanced through the support of graduate students and participation in outreach activities.

提出了一个现场计划，以检查混合边界流体与分层内部的交换，通过测量蒙特雷潜艇和其他几个峡谷中的湍流，内波和肾上腺层的交换。将解决几个问题：1。大陆斜坡内波驱动的边界混合对海洋区域分层的净影响是什么？2。峡谷中的罚款参数是否比在公海中发现的更连贯的内部波场在峡谷中降低了5 6倍，或者（ii）与地形的相互作用更连贯？微观结构剖面，以及配备ADCP和Thermistor链的系泊的底部120 m的速度和温度剖面时间序列。这些数据将通过（i）与边界湍流耗散速率一起确定内部波能通量进入边界的内部波能通量来量化BBL能量预算，以及（ii）表征肾上腺层的分布。能量频率差异将用于识别峡谷内的内波源和下沉，而潜在的外部来源将从深水通量中识别出来。此外，还将探索新的分析技术，包括（i）使用能量通量的共光谱来诊断内部波的反射，从近乎危险的底部斜率中诊断出内波反射，（ii）双效性来评估高垂直波形和低垂直波形（III）动量之间的关系，以评估底层拖动和（iv）的液压效果，以确定效果的底层和（iv）的交换，以确定频道的交换。这项工作与维多利亚大学的埃里克·库兹（Eric Kunze）合作，后者将进行微观结构测量并参与整个数据集的分析和解释。它将受益于ONR 2006年AESOP计划期间蒙特雷湾以南的坡度的最新建模工作和测量。IntlectualFure：我们是出于有关（i）关于（i）在边界上将流体交换与分层内部混合的液体交换及其在全球混合和热 - 果碱循环中的作用的基本问题的动机。调查计划结合了空间覆盖范围和高频时间，以允许对重要性进行严格的测试。与迄今在实验室外实现的核心XCP模式涵盖了半潮汐潮汐的完整周期，将在空间和时间上更好地分辨出一个连贯的内部波场，以便更好地了解通过倾斜地形附近的内部波场的能量级联。此外，其他大陆斜坡峡谷中的探索性测量将有助于扩大对全球范围的适用性。Boader的影响：多机构的合作将促进对蒙特雷峡谷和其他大陆Slope Canyons混合过程的跨学科理解，这是营养，泥沙，沉积物和化学探针的本地预算的重要方面。通过罚款混合参数化的完善，它还将有助于大规模混合预算和可能的气候模型预测。教育将通过研究生的支持并参加外展活动进行教育。