Collaborative Research: The Heated Wind- and Wave-Driven Ocean Surface Boundary Layer: Synergistic Analyses of Observations and Simulations

合作研究：受热的风和波浪驱动的海洋表面边界层：观测和模拟的协同分析

• 批准号: 2316818
• 负责人: Seth Zippel
• 金额: $ 30.74万
• 依托单位: Oregon State University
• 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: 2022-10-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2316818&HistoricalAwards=false
• 关键词: Collaborative; Research; Heated; Wind; Wave; Collaborative; Research; Heated; Wind; Wave

The ocean's surface layer in contact with the atmosphere (or surface boundary layer -- OSBL) controls climate, weather, and Earth system dynamics by coupling the ocean and atmosphere through air-sea fluxes. Turbulence in the OSBL distributes biogeochemical and ecologically relevant tracers that are floatable (buoyant), such as plankton, bubbles, nutrients, oil, and microplastics. Wind and waves drive OSBL turbulence in several critical ways: Wind-generated ocean currents; wave-current interactions result in wind-aligned vortices, called Langmuir turbulence (LT); and breaking waves inject turbulent kinetic energy to the subsurface . The present conceptual and theoretical framework of wave-driven OSBL dynamics is largely based on conditions for which surface heat fluxes are assumed to be either neutral or conducive to overturn the surface water column. However, diurnal heating or rain events prevent overturning and are omnipresent over the world oceans. This project would use numerical simulations and analysis of existing data sets to explore the effects of surface waves on the stratified OSBL in surface heating conditions. The objectives of this study are to: (1) identify limitations of traditional surface boundary assumptions due to wave effects; (2) reveal the dynamics of wave effects on the heated OSBL, based on a systematic analysis of momentum, buoyancy, and turbulent kinetic energy; (3) integrate data and simulations to establish a turbulence regime diagram that reveals the conditions in which Langmuir turbulence (LT) and breaking wave effects affect OSBL dynamics; (4) perform an analysis of turbulence statistics to assess and proposes improved ocean mixing parameterizations. These new parameterizations will be applied to demonstrate the importance of wave effects on the transport of buoyant tracers during diurnal OSBL heating. The work will be relevant across many oceanographic and atmospheric sub-disciplines; support an early career researcher; train graduate students; and engage in outreach. The proposed research will test specific hypotheses: (1) wave effects on heated OSBL dynamics are significant and quantifiable through observations and simulations; (2) LT is essential for OSBL mixing but sufficiently strong heating generates favorable conditions for shear-driven turbulence due to jets; (3) breaking waves prevent flow laminarization in strong heating conditions; and (4) wave-driven mixing in heated OSBLs can be accurately represented in improved turbulent mixing parameterizations to capture accelerated jet transport and the deep submergence of buoyant tracers. The team has access to several extensive observational data-sets, from which they will be able to determine the presence of LT during surface heating and assess the impact of LT on OSBL dynamics. Numerical experiments will be conducted using Large Eddy Simulations (LES) which produce LT through vortex forcing and include effects from breaking waves. Based on results from a combined data, LES modeling analysis, physics-motivated and practical mixing parameterizations for the heated OSBL will be developed, assessed, and applied to transport of buoyant tracers, such as microplastics, plankton or oil.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.

海洋的表面层与大气（或表面边界层 - OSBL）接触，通过通过空气通量耦合海洋和大气来控制气候，天气和地球系统动力学。 OSBL中的湍流分布了可漂浮（浮力）的生物地球化学和生态相关的示踪剂，例如浮游生物，气泡，营养素，油和微塑料。风和海浪以几种关键的方式驱动OSBL湍流：风产生的洋流；波流相互作用导致风对准涡流，称为langmuir湍流（LT）；并破坏波向地下注入湍流动能。波动驱动的OSBL动力学的当前概念和理论框架主要基于认为表面热通量被认为是中性或有助于推翻地表水柱的条件。但是，昼夜供暖或降雨事件可防止推翻，并且在世界海洋上无所不在。该项目将使用数值模拟和现有数据集的分析，以探索表面加热条件下的地表波对分层OSBL的影响。这项研究的目标是：（1）确定由于波浪效应引起的传统表面边界假设的局限性； （2）基于对动量，浮力和湍流动能的系统分析，揭示了波浪对加热OSBL的动力学； （3）整合数据和模拟以建立湍流制度图，该图揭示了Langmuir湍流（LT）和破坏波效应影响OSBL动力学的条件； （4）对湍流统计数据进行分析，以评估并提出改进的海洋混合参数化。这些新的参数化将用于证明在昼夜OSBL加热过程中波浪影响对浮力示踪剂的运输的重要性。这项工作将与许多海洋学和大气子学科有关；支持早期职业研究员；培训研究生；并进行外展。 拟议的研究将检验特定的假设：（1）通过观察和模拟对加热OSBL动力学的波浪影响是显着且可量化的； （2）LT对于OSBL混合是必不可少的，但足够强的加热会产生有利的条件，以使剪切驱动的湍流是由于喷气机引起的； （3）断裂波阻止在强加热条件下流动层流； （4）在加热OSBL中的波驱动混合可以在改进的湍流混合参数化中准确表示，以捕获加速的喷气运输和浮力示踪剂的深层浸没。该团队可以访问几个广泛的观察数据集，他们将能够从中确定表面加热期间LT的存在并评估LT对OSBL动力学的影响。数值实验将使用大型涡流模拟（LES）进行，这些模拟（LES）通过涡流强迫产生LT，并包括断裂波的效果。根据合并数据的结果，LES建模分析，将针对加热OSBL的物理动机和实用的混合参数进行开发，评估和应用于浮动示踪剂的运输，例如微塑料，Plankton或Oil。这一奖项奖励NSF的法定任务，反映了NSF的法定范围，并已通过评估构成群体的范围和众所周知的构成师的支持。