Wave Breaking in High Winds and its Effects on the Air-Sea Exchange of Gases of Varying Solubility

海洋是储存和转移许多温室气体的主要角色。 了解这些气体通过海洋和大气之间界面的量，即海气通量，对于准确的地球化学和气候预测至关重要。 移动的气体通过界面的机制是太小了，大多数耦合的海洋大气模式解决，因此参数化的小尺度过程的影响。 海气通量主要由风速决定，但对许多其他环境因素如表面波和表面活性剂也很敏感。 现场观测表明，观测到的海气通量和参数化的海气通量之间存在很大的变异性，特别是在高风速条件下，这表明风速本身无法捕捉影响海气交换的所有因素。 该项目将分析在格陵兰岛南端附近的NSF资助的研究项目期间收集的数据集。 这个数据集是独特的，可以提供一些以前未测量的机制与控制海气通量，如破碎波和泡沫形成大风。 研究结果有助于完善气体转移参数化，而这反过来又有助于限制对气候敏感气体的区域和全球估计。 该项目将支持一名博士生的培训，并为K-12教师编写关于气体交换、风暴、碎浪和气候变化研究的激励性教材。全球海气通量估计基于气体传输速度k的参数化。对于一阶，k由风速（U）决定，并且通常被参数化为U的非线性函数。然而，有一个大的传播k预测的传统参数化，特别是在高风速。这是由于各种各样的环境强迫和过程，实际上影响k，这表明风速本身不能捕捉空气-水气体交换的变化。在高风速下，破碎波成为估算气体通量时要考虑的关键因素。波浪破碎导致额外的上层海洋湍流和气泡云的产生。在这里，我们建议分析在2013年的大风气体交换研究实验期间收集的各种数据集，以了解和量化破碎波对气体传输速度的控制。这将是第一个研究连接湍流动能耗散率导致的波浪破碎的气体传输速度。从观察中获得的见解将被纳入物理气体传输模型。白浪覆盖范围和破碎波统计数据将根据从研究船Knorr的飞桥的左舷和右舷获取的可见图像确定。将考虑溶解度极高（甲醇和丙酮）和溶解度较低（二氧化碳、二甲基硫醚）的气体，以对比波破碎介导的转移程度。海况条件将根据激光高度计和乘波浮标测量值计算。涡协方差通量和海水浓度的二氧化碳，二甲基硫，甲醇和丙酮允许直接计算的传输速度。

The ocean is a major player in the storage and transfer of many greenhouse gases. Understanding the amount of these gases going through the interface between ocean and atmosphere, known as the air-sea flux, is of upmost importance to accurate biogeochemical and climate predictions. The mechanisms which move the gases through the interface are too small to be resolved by most coupled ocean atmosphere models, and are therefore parameterized to account for the effect of the small scale processes. Air-sea fluxes are largely dictated by wind speed, but are sensitive to many other environmental factors such as surfaces waves and surfactants. In situ observations have shown large variability between observed and parameterized air-sea fluxes, especially under high wind speed conditions, suggesting wind speed alone cannot capture all of the factors that influence air-sea gas exchange. This project will analyze a dataset collected during a NSF-funded research project near the southern tip Greenland. This dataset is unique and may offer insight into some previously unmeasured mechanisms with control on air-sea gas flux such as breaking waves and bubble formation under high winds. The findings could help to refine gas transfer parameterizations which, in turn, would help to constrain regional and global estimates of climate sensitive gases. The project will support the training of a PhD student and the development of stimulating teaching materials about research into gas exchange, storms, breaking waves and climate change, available to K-12 teachers. Global air-sea gas flux estimates are based on parameterizations of the gas transfer velocity k. To first order, k is dictated by wind speed (U) and is typically parameterized as a non-linear function of U. There is, however, a large spread in k predicted by the traditional parameterizations, especially at high wind speed. This is due to a large variety of environmental forcings and processes that actually influence k, suggesting wind speed alone cannot capture the variability of air-water gas exchange. At high wind speed, breaking waves become a key factor to take into account when estimating gas fluxes. Wave breaking results in additional upper ocean turbulence and generation of bubble clouds. Here, we propose to analyze the diverse data set collected during the High Wind Gas exchange Study experiment in 2013 to understand and quantify the control of breaking waves on gas transfer velocities. This will be a first study linking turbulent kinetic energy dissipation rates resulting from wave breaking to gas transfer velocities. Insights gained from observation will be incorporated into physical gas transfer models. Whitecap coverage and breaking wave statistics will be determined from visible imagery acquired from the port and starboard side of the flying bridge of the Research Vessel Knorr. Both very soluble (Methanol and Acetone) and less soluble (Carbon Dioxide, Dimethyl Sulfide) gases will be considered, allowing to contrast the degree of wave breaking mediated transfer. Sea state conditions will be computed from laser altimeter and wave rider buoy measurements. Eddy covariance fluxes and sea water concentration of Carbon Dioxide, Dimethyl Sulfide, Methanol and Acetone allow for direct calculation of transfer velocities.