Turbulent Exchange: Aerosols, Bubbles And Gases

湍流交换：气溶胶、气泡和气体

• 批准号: NE/J022373/2
• 负责人: Helen Czerski
• 金额: $ 39.75万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ022373%2F2
• 关键词: Turbulent; Exchange; Aerosols; Bubbles; Gases

There is now a consensus that global climate is changing in response to increasing atmospheric concentrations of greenhouse gases. These gases have natural as well as man-made sources and sinks. For carbon dioxide the largest sink is the ocean, which absorbs between 30% and 50% of the CO2 generated by the burning of fossil fuel. The direction of the exchange of gases between atmosphere and ocean depends on the difference in gas concentration between the air and water, and on a number of physical processes that modify the rate of the exchange. The most important of these processes is turbulent mixing in both the air and water close to the surface. This increases with wind speed, but the relationship is complicated by other factors such as the waves state and the thermodynamic stability of the near-surface layers of both ocean and atmosphere. At high wind speeds wave breaking generates bubbles, mixing air down into the water column. The presence of bubbles increases the rate of gas exchange, but the detailed nature of the process is not fully understood and there is considerable disagreement about the exact form of the equations that describe the rate of gas transfer. This is largely a result of a lack of sufficiently detailed measurements.Wave breaking and bubbles are also closely linked to the formation of sea-spray aerosol particles - these are important as cloud condensation nuclei. Aerosols are generated by the bursting of bubbles at the sea surface. The rate of aerosolformation is often expressed as a function of whitecap fractions on the sea surface, but there is an uncertainty of about a factor of 10 in the production rate. This suggests that whitecap fraction alone does not control the production rate, but thatfactors such as the size and number of bubbles produced by breaking waves may vary with other factors such as size or steepness of the wave.This project is a UK contribution to a US research cruise that aims to examine the impact of wave breaking and bubble processes on air-sea gas exchange. We will measure whitecap fraction, wave state, wave breaking statistics, and bubbleproperties beneath breaking waves. Measurements will be made from an 11-m spar buoy equipped with wave wires to measure the local wave height at high spatial resolution, a bubble camera to measure large bubbles near the surface, and2 acoustical resonators to measure smaller bubbles deeper below the surface. A separate Waverider buoy will also be deployed to make longer term and independent measurements of the wave spectra. On the ship we will make direct measurements of aerosol fluxes via the eddy covariance technique, along with those of heat, water vapour, CO2, and momentum. Our partners from NOAA and the University of Hawi'i will measure fluxes of several different gases: CO2, CO, and DMS. The joint measurements of gas fluxes, and whitecap and bubble properties will allow the influence of bubbles on the flux to be evaluated directly against a variety of existing parameterizations.

现在已经达成共识，全球气候因增长的温室气体浓度而变化。这些气体具有天然和人造的来源和水槽。对于二氧化碳，最大的水槽是海洋，海洋吸收了化石燃料燃烧产生的二氧化碳的30％至50％。大气与海洋之间气体交换的方向取决于空气和水之间气体浓度的差异，以及许多修改交换速率的物理过程。这些过程中最重要的是在靠近表面的空气和水中混合湍流。这随风速的增加而增加，但是这种关系因海浪状态和海洋和大气的近地面层的热力学稳定性而变得复杂。在高风速下，波浪破裂会产生气泡，将空气向下混合到水柱中。气泡的存在增加了气体交换速率，但是该过程的详细性质尚未完全了解，并且在描述描述气体传递速率的方程式的确切形式上存​​在很大分歧。这在很大程度上是由于缺乏足够详细的测量结果。断裂和气泡也与Sea -Spray气溶胶颗粒的形成密切相关 - 这些很重要，因为云凝结核。气溶胶是通过海面的气泡破裂而产生的。气化速率通常表示是海面上白ecap分数的函数，但生产率的不确定性约为10倍。这表明，单独的白色分数不能控制生产率，但是诸如破坏波产生的气泡的大小和数量可能会随其他因素（例如大小或波浪的陡度）而变化。该项目是英国对美国研究巡游的贡献，目的是研究波浪破裂和气泡进程对空气气体气体交换的影响。我们将测量白核分数，波浪状态，波浪破裂统计和破裂波下方的泡泡性。测量结果将由配备波线的11米SPAR浮标进行测量，以在高空间分辨率下测量局部波高度，一个气泡摄像头，以测量表面附近的大气泡，和2个声学谐振器，以测量在表面下方更深入的较小气泡。还将部署一个单独的Waverider浮标，以进行长期和独立的波光谱测量。在船上，我们将通过涡流协方差技术以及热，水蒸气，二氧化碳和动量直接测量气溶胶通量。来自NOAA和HAWI'I大学的合作伙伴将测量几种不同气体的通量：CO2，CO和DMS。气通量的关节测量以及WhiteCap和气泡特性将使气泡对通量的影响直接评估用于各种现有参数化。

项目成果

Ocean bubbles under high wind conditions. Part 1: Bubble distribution and development

大风条件下的海洋气泡。

• DOI: 10.5194/os-2021-103
• 发表时间: 2021
• 作者: Czerski H

Ocean bubbles under high wind conditions. Part 2: Bubble size distributions and implications for models of bubble dynamics

大风条件下的海洋气泡。

• DOI: 10.5194/os-2021-104
• 发表时间: 2021
• 作者: Czerski H

Ocean bubbles under high wind conditions - Part 1: Bubble distribution and development

• DOI: 10.5194/os-18-565-2022
• 发表时间: 2022-05-03
• 期刊: OCEAN SCIENCE
• 影响因子: 3.2
• 作者: Czerski, Helen;Brooks, Ian M.;Blomquist, Byron
• 通讯作者: Blomquist, Byron

Toward omnidirectional and automated imaging system for measuring oceanic whitecap coverage.

用于测量海洋白浪覆盖范围的全向自动化成像系统。

• DOI: 10.1364/josaa.33.001589
• 发表时间: 2016
• 期刊: Journal of the Optical Society of America. A, Optics, image science, and vision
• 作者: Al-Lashi RS

Wind Speed and Sea State Dependencies of Air-Sea Gas Transfer: Results From the High Wind Speed Gas Exchange Study (HiWinGS)

• DOI: 10.1002/2017jc013181
• 发表时间: 2017-10-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
• 影响因子: 3.6
• 作者: Blomquist, B. W.;Brumer, S. E.;Pascal, R. W.
• 通讯作者: Pascal, R. W.