Collaborative Research: Autonomous sampling of upper ocean mixing in the Southern Ocean due to wind forcing and double-diffusion

南大洋吸收了大约一半的人为碳，而进入海洋的大气热量中更大的一部分则来自南大洋。南大洋是全球海洋中唯一一个通过经向翻转环流（MOC）连接三大大洋盆地的区域。尽管该地区很重要，但由于其偏远的位置和恶劣的条件，该地区的采样不足。南大洋观测资料的缺乏不仅限于海洋测量。气象测量，如风速和热通量是稀缺的，往往从传感器安装在稀疏的船舶交通。随着自主平台的成熟，现在有机会在南大洋的各种条件下收集高分辨率的空间和时间测量数据。虽然气候模式取得了长足的进步，但未解决的混合过程的代表性不足仍然是一个重要的误差来源。这可能在海洋近地表边界层中最为严重，在南大洋，Langmuir物理、锋面过程和双重扩散都很活跃，但由于缺乏观测，在发展参数化方面进展缓慢。这项新颖的观测研究将允许在空间和时间尺度上对该地区的上层海洋物理进行采样，采样时间比以前的实验要短得多，从而可以对风和辐射强迫的惯性和日过程进行分辨率，并在空间尺度上深入了解影响上层海洋的湍流级联。该项目的结果将导致在海洋环流、海洋-大气耦合系统和气候模式的数值模式中对亚网格尺度过程进行更现实的参数化。拟议中的项目将通过耶鲁大学女性科学协会（WISAY）招募两名本科生暑期研究员，为她们提供使用自主平台进行海洋采样的实践经验。这个项目的动机是需要了解全球海洋的翻转环流，这一地区既有丰富的小规模物理过程，也有严重的采样不足。这种循环控制着巨大的海洋水库中热量和二氧化碳的运输和储存，因此在调节地球气候方面起着重要作用。该项目的具体目标是：1)与表面波光谱数据和气象测量相结合，获得1000 m以上湍流耗散率、温度、盐度和荧光的测量值。自主平台的使用将提供具有空前的南大洋混合空间和时间分辨率的数据集；2)研究上层海洋对南大洋极端表面强迫（风应力、辐射通量）的湍流响应。该数据集将消除船载测量的天气偏差，并将为该地区亚中尺度和边界层动力学的理论和模型研究提供动力。这项研究将在德雷克海峡和阿根廷盆地之间的太平洋行政协调会锋面区域进行。波浪滑翔机和漂流器星座将测量风、波、空气温度和辐射量，以及海面温度和盐度。装有微结构传感器的滑翔机将测量涡旋场活跃、水团相互作用的水柱上方1000米的温度、盐度、精细结构和湍流，以及海洋与大气相互作用的近地表边界层。在部署结束时，滑翔机阵列将在阿根廷盆地的海洋观测倡议地点周围采样，以验证波浪滑翔机的气象测量结果。该数据集将为研究该地区混合率的物理基础提供机会，同时为建模社区提供有价值的见解。

The Southern Ocean is responsible for about half the uptake of anthropogenic carbon and an even larger fraction of the atmosphere's flux of heat into the sea. The Southern Ocean is the only sector of the global ocean that connects all three major ocean basins through the Meridional Overturning Circulation (MOC). Despite its importance, the region is under sampled largely due to its remote location and severe conditions. The dearth of observations in the Southern Ocean is not limited to ocean measurements. Meteorological measurements such as wind speed and heat fluxes are scarce and often from sensors mounted on sparse ship traffic. With the maturing of autonomous platforms, there is now an opportunity to collect high-resolution spatial and temporal measurements in the full range of conditions characteristic of the Southern Ocean. While climate models have advanced substantially, the inadequate representation of unresolved mixing processes is still a significant source of error. This is perhaps the most severe in the near-surface boundary layer of the ocean where Langmuir physics, frontal processes, and double-diffusion are active in the Southern Ocean, yet the lack of observations have slowed progress in developing parameterizations. This novel observational study will allow sampling of the upper-ocean physics of this region on spatial and timescales much shorter than those sampled during previous experiments, allowing the resolution of inertial and diurnal processes forced by winds and radiation, and on spatial scales that give insight into the turbulent cascade influencing the upper ocean. The results from this project will lead to more realistic parameterizations of subgrid-scale processes in numerical models of ocean circulation, of the coupled ocean-atmosphere system and of climate models. The proposed project will recruit two undergraduate summer fellow through the Women in Science At Yale (WISAY) to provide them hands-on experience in using autonomous platforms to sample the ocean.This project is motivated by the need to understand the overturning circulation of the global ocean in a region that is both rich in small-scale physical processes and severely under-sampled. This circulation governs the transport and storage of heat and carbon dioxide within the huge oceanic reservoir, and thus plays a major role in regulating the Earth's climate. The specific goals of this project are to 1) obtain measurements of turbulent dissipation rates, temperature, salinity and fluorescence in the upper 1000 m collocated with surface wave spectral data and meteorological measurements. The use of autonomous platforms will provide a dataset with unprecedented spatial and temporal resolution of mixing in the Southern Ocean and 2) investigate the turbulent response of the upper ocean to the extreme surface forcing (wind stress, radiative fluxes) in the Southern Ocean. The dataset will eliminate the fair-weather bias of shipboard measurements and will provide motivation for theoretical and model studies of submesoscale and boundary layer dynamics in the region. The study will be conducted in the region of the ACC fronts between Drake Passage and the Argentine Basin. A Wave Glider and drifter constellation will measure wind, waves, air temperature and radiation quantities, and sea surface temperature and salinity. Gliders with microstructure sensors will measure temperature and salinity fine structure and turbulence in the upper 1000 m of the water column where the eddy field is active and water masses interact, and in the near-surface boundary layer where the ocean interacts with the atmosphere. At the end of the deployment the glider array will sample around the Ocean Observatory Initiative site in the Argentine basin to validate the meteorological measurements from the wave glider. This dataset will provide an opportunity to study the physics underpinning mixing rates in this region, while simultaneously contributing valuable insights to the modeling community.