Capturing Oceanic Submesoscales, Stirring, and Mixing with Sound and Simulations

全球海洋就像一块海绵，吸收了大量由于人类活动而增加到大气中的多余热量和碳。因此，我们的海洋在减缓气候变化方面发挥着关键作用。然而，海洋海绵未来的储存能力是不确定的，此外，营养物质和氧气的分布也是不确定的，而营养和氧气是健康海洋生态系统的关键成分。为了解决这些不确定性，我们需要更好地了解海洋是如何在表层以下深处流动的——特别是跨越数十米到数百公里尺度的洋流，也就是所谓的亚中尺度。亚中尺度洋流很重要，因为它们提供了一条途径来利用风和潮汐的能量，并利用它来搅拌和混合全球不同的水团，以及它们携带的热量、碳和营养物质。尽管它们很重要，但由于它们的中等大小和间歇性，人们对海洋亚中尺度知之甚少。这意味着它们都很难在自然界中被捕获或用计算机建模。在这个项目中，我的团队将进行一个开创性的实验，首次捕捉到存在于海洋表层之下的全部洋流，以及它们产生的混合和搅拌。一项目标明确的航海计划将使用主动声学技术，以前所未有的分辨率（比其他技术好两个数量级）对海洋进行采样，并充分捕捉亚中尺度洋流。与蝙蝠的回声定位类似，水面上的船只向水中释放声脉冲，并记录水层的反射。声学测量将首次与尖端机器人技术、船舶安装和系泊仪器相结合。同时，利用我们新的海洋观测数据，最先进的模式模拟将得到验证和改进。结果将是迄今为止地表下海洋最真实的代表。模拟将用于量化亚中尺度的启动、普遍性和相互作用，并评估它们在推动全球海洋能源和财产交换中的作用。这项实验将在全球海洋活动热点：阿根廷海岸外的巴西-马尔维纳斯汇合处进行。在这里，来自大西洋的亚热带水域与来自南大洋的极地水域相撞。这种汇合处的水团交换很可能是由亚中尺度洋流驱动的，在全球海洋中热、盐、碳和维持生命的营养物质和氧气的分布中起着关键作用。通过在巴西-马尔维纳斯汇合处以无与伦比的细节揭示海洋内部动力学，COSSMoSS将揭示科学海洋之谜中缺失的重要部分，帮助我们更好地了解我们未来的生物圈和气候。

The global oceans act as a sponge, soaking up significant amounts of the excess heat and carbon that have been added to the atmosphere due to human activity. Our oceans therefore play a key role in buffering the magnitude of climate change. However, the future storage capacity of the ocean sponge is uncertain, alongside the distribution of nutrients and oxygen, key ingredients for a healthy marine ecosystem. To address these uncertainties, we need to better understand how the oceans flow deep below the surface layers - in particular current flows that span scales of tens of metres to hundreds of kilometers, otherwise known as submesoscales. Submesoscale currents matter because they provide a pathway to harness energy from the winds and tides and use it to stir and mix different water masses around the globe, along with the heat, carbon and nutrients that they carry. Despite their importance, little is known about ocean submesoscales because of their intermediate size and intermittent nature. This means they are both difficult to capture in nature or model with computers. In this project, my team will conduct a pioneering experiment that will capture for the first time the full range of current flows that exist beneath the surface ocean layers, alongside the mixing and stirring that they generate. A targeted sea-going programme using active acoustics will sample the ocean at unprecedented resolutions (two orders of magnitude better than other techniques) and fully capture submesoscale currents. Similar to how bats echo-locate, a ship at the surface releases sound pulses into the water and records reflections from water layers. Acoustic measurements will be combined for the first time with cutting-edge robotics, vessel-mounted and moored instrumentation. In parallel, state-of-the-art model simulations will be both validated and improved using our new ocean observation data. The result will be the most realistic representation of the sub-surface ocean to date. The simulations will be used to quantify submesoscale initiation, ubiquity and interactions, and assess their role in driving energy and property exchanges in the global ocean. The experiment will take place at a global hotspot of ocean activity: the Brazil-Malvinas Confluence off the coast of Argentina. Here sub-tropical waters from the Atlantic collide with polar waters from the Southern Ocean. Water mass exchanges at this confluence, which are likely driven by submesoscale currents, play a key role in the distribution of heat, salt, carbon and life sustaining nutrients and oxygen throughout the global oceans. By revealing interior ocean dynamics in unparalleled detail at the Brazil-Malvinas Confluence, COSSMoSS will shed light on a significant missing piece of the scientific ocean puzzle helping us to better understand our future biosphere and climate.