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：
1924686
负责人：
Leonel Romero
金额：
$ 29.31万
依托单位：
University of California-Santa Barbara
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2021-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924686&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.

这个项目将在全面的建模框架内研究气体传输的空间变异性。理论和建模研究在相对较小的尺度上一致，在相对较小的尺度上，由于地球的旋转，运动，尤其是沿垂直方向的运动越来越统治，尤其是沿垂直方向变得越来越大，对海洋生物地球化学和空气磁通的影响明显。但是，没有研究集中在波动变异性和相关气泡中介导波电流相互作用引起的气体转移。当今气体传输系数的大多数参数化取决于风速，而不是波动动力学的更详细的表示，从而导致大量不确定性。最近的参数化包括通过积分波参数（例如明显的波高或波动年龄）的波浪效应，这都无法解释由于尖锐前沿处的波流相互作用而引起的调制。最近开发的波浪破坏统计模型提供了一个框架，可以明确说明空气夹带和气泡介导的气体通量。该模型适用于耦合的接地系统模拟，提供了一个独特的机会，可以研究波流相互作用对气泡介导的气体转移和通量变异性的影响。结果将在气候研究中直接应用。他们可以解释沿海环境中观察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，本科生将参加研究。该项目将通过为西班牙裔，早期职业科学家的职业做出贡献，并通过向指定的西班牙裔服务机构UCSB揭露学生的职业，从而增强代表性不足的群体的参与。这项工作的总体目标是研究由于子镜下的波电流相互作用而引起的气泡介导的气体转移的调节。该建模基于表面波破裂和相关空气通量的最新进展，该进展为基于物理的框架提供了模型的气泡介导的气体传递系数。现实的数值模拟将用于研究气泡介导的气体转移的空间变异性及其对气体通量的影响（即CO2）。初步模型结果表明，逼真的风和电流强迫的波浪破坏统计数据证实了先前的观察结果和对波电流调节的理论分析，其中，在倾向与海洋阵线对齐的风中，在条件下，波浪破裂的增强。通过在子镜下增加模型分辨率的增加，通过电流的波动调制得到了增强。子尺度的额叶表面收敛和下降速度与区域重叠，并随着倾斜的风力强迫而增强的波浪破裂。假设在这些条件下，空气气体通量会增强。在上升条件下，将通过在东部边界电流处使用数值模拟对此进行测试。上升区域已显示出二氧化碳浓度的显着差异，但尚不清楚。溶解的二氧化碳将被建模，以忽略从背景平衡水平开始的生物和化学反应，然后用逼真的通量强迫，包括气泡介导的转移系数。该假设将通过将不同决议的模型解决方案与使用仅取决于风速的标准传输系数参数化的控制运行进行比较。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛影响的审查标准通过评估来进行评估的。