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Modulation of Bubble-Mediated Gas Transfer due to Wave-Current Interactions

波流相互作用对气泡介导的气体传输的调节

基本信息

批准号：
2121646
负责人：
Leonel Romero
金额：
$ 29.31万
依托单位：
University of Connecticut
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-01 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2121646&HistoricalAwards=false
关键词：
Modulation Bubble Mediated Gas Transfer

项目摘要

This is project will study the spatial variability of gas transfer across the air-sea interface within a comprehensive modeling framework. Theoretical and modeling studies agree at relatively small scales, where the flow becomes less dominated by the rotation of the earth, motion, especially along the vertical direction becomes more energetic, with pronounced impacts on ocean biogeochemistry, and air-sea fluxes. However, no study has focused on wave breaking variability and related bubble mediate gas transfer due to wave-current interactions. Most parameterizations of gas transfer coefficients today depend on wind speed rather than more detailed representation of wave dynamics, resulting in large uncertainties. Recent parameterizations include wave effects through integral wave parameters such as significant wave height or wave age, neither which can explain the modulation due to wave-current interactions at sharp fronts. A recently developed model of wave breaking statistics provides a framework to explicitly account for breaking on air entrainment and bubble-mediated gas fluxes. The model is suitable for coupled earth system simulations providing a unique opportunity to study the effect of wave-current interactions on the variability of bubble-mediated gas transfer and fluxes. The results will have direct applications for climate studies. They can explain the uncertainty of the observed gas fluxes in coastal environments, helping to reduce the uncertainty of global CO2 budgets. Other impacts include training students. Specifically, an undergraduate student will participate in the research. The project will enhance the participation of underrepresented groups by contributing to the career of a Hispanic, early-career scientist, and by exposing the students at UCSB, a designated Hispanic-Serving Institution, to the research and its results. The overarching goal of the work is to investigate the modulation of bubble-mediated gas transfer due to wave-current interactions at submesoscales. The modeling is based on recent advances on surface wave breaking and related air-sea fluxes, which provide a physics-based framework to model bubble-mediated gas transfer coefficients. Realistic numerical simulations will be used to investigate the spatial variability of bubble-mediated gas transfer and their impact on gas fluxes (i.e., CO2). Preliminary model results show that wave breaking statistics forced by realistic winds and currents confirm previous findings from observations and theoretical analysis on the modulation of waves by currents, where wave breaking is enhanced in conditions with winds obliquely aligned with ocean fronts. The wave breaking modulation by currents is enhanced with increasing model resolution at submesoscales. Submesoscale frontal surface convergence and downwelling velocities overlap with areas with enhanced wave breaking with oblique wind forcing. It is hypothesized that under these conditions air-sea gas fluxes are enhanced. This will be tested with numerical simulations at an eastern boundary current during upwelling conditions. Upwelling areas have been shown to exhibit significant variability in CO2 concentrations that is not well understood. Dissolved CO2 will be modeled neglecting biological and chemical reactions starting from a background equilibrium level and then forced with realistic fluxes, including bubble-mediated transfer coefficients. The hypothesis will be tested by comparing model solutions at varying resolutions against a control run using standard transfer coefficient parameterizations that depend only on wind speed.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.

这个项目将在一个综合的模拟框架内研究气体在海气界面上传输的空间变化。理论和模拟研究在相对较小的尺度上一致，在这些尺度上，流动不再受地球自转的支配，运动，特别是沿着垂直方向的运动变得更加活跃，对海洋地球化学和海气通量产生明显影响。然而，还没有研究关注波流相互作用引起的波浪破碎变异性和相关的气泡介导的气体传输。目前，大多数气体传输系数的参数化依赖于风速，而不是更详细的波浪动力学表示，导致很大的不确定性。最近的参数化包括通过积分波参数（例如有效波高或波龄）的波浪效应，但这两种参数都无法解释由于尖锋处波流相互作用而产生的调制。最近开发的模型波破碎统计提供了一个框架，明确占破碎的空气夹带和气泡介导的气体通量。该模型是适合耦合地球系统模拟提供了一个独特的机会，研究波流相互作用的气泡介导的气体传输和通量的变化的影响。研究结果将直接应用于气候研究。它们可以解释在沿海环境中观测到的气体通量的不确定性，有助于减少全球二氧化碳预算的不确定性。其他影响包括培训学生。具体来说，一名本科生将参加这项研究。该项目将通过促进西班牙裔，早期职业科学家的职业生涯，并通过暴露在UCSB，一个指定的西班牙裔服务机构的学生，研究及其结果，提高代表性不足的群体的参与。这项工作的首要目标是调查的调制气泡介导的气体传输由于波流相互作用在亚中观尺度。该模型是基于最新进展的表面波破碎和相关的海气通量，提供了一个基于物理的框架来模拟气泡介导的气体传输系数。真实的数值模拟将用于研究气泡介导的气体传输的空间变化及其对气体通量的影响（即，CO2）。初步的模型结果表明，破波统计迫使现实的风和电流确认以前的调查结果，从观察和理论分析的调制波电流，其中破波增强的条件下，风斜对齐与海洋锋。在亚中尺度下，随着模型分辨率的增加，海流对波浪破碎的调制作用增强。次中尺度锋面辐合和下沉速度与斜风强迫下波浪破碎增强的区域重叠。据推测，在这些条件下，海气通量增强。这将在上升流条件下，在东部边界电流的数值模拟进行测试。上升流地区已被证明表现出显着的变化，在CO2浓度，这是不是很好地理解。溶解的CO2将被建模，从背景平衡水平开始忽略生物和化学反应，然后强制与现实的通量，包括气泡介导的传输系数。该假设将通过比较不同分辨率的模型解决方案与使用仅取决于风速的标准传递系数参数化的控制运行来测试。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评估被认为值得支持影响审查标准。