Investigating ocean stratification changes with global warming by long-range internal tides

层结是海洋的一个重要性质，在几乎所有海洋过程中起着重要作用，包括物质输送、垂直混合和翻转环流。在全球范围内监测其季节循环、十年趋势和年际变化是一个高度优先事项。长期内潮是监测海洋层结变化的自然选择，它的存在归因于海洋层结。这一项目将使利用卫星测高精确观测低模式内潮的技术进一步成熟。它不仅将提高我们对内潮活动的认识，而且还将发展一种监测海洋分层的新技术，提供一个独立的长期、低成本、环境友好的观测系统。全球海洋经常发生变化，如热浪和热带气旋等极端天气。除了海洋变暖和海平面上升，众所周知，层化加剧可能会改变大规模的海洋环流;一个极端的场景在电影“后天”中展示。卫星产生的内潮模型将有助于海洋学界设计实地实验、模拟内潮、初级生产力、海洋声学、珊瑚礁漂白、海洋混合和内潮校正。有关海洋分层变化的新资料将免费提供给地球仪各地的研究人员。这个项目将在华盛顿大学培养一名研究生。海洋分层在许多动力学过程中起着重要的作用，包括物质输送、等密度线混合和纬向海洋环流。该项目将利用卫星测高、世界海洋地图集、Argo浮标和ECCO和HYCOM两个数值模型调查海洋分层变化。它的目标是：（1）利用长期内潮束建立一个全球网络，（2）根据内潮速度量化海洋分层的季节循环、年代际趋势和年际变化，（3）用现场测量验证卫星获得的海洋分层变化，以及（4）评估ECCO和HYCOM在再现海洋分层方面的表现。该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响评审标准。

Stratification is a key property of the ocean and plays an important role in almost all ocean processes including mass transport, vertical mixing and overturning circulation. It is of high priority to monitor its seasonal cycle, decadal trend and interannual variation on the global scale. Long-range internal tides, which attribute their existence to ocean stratification, are a natural choice for monitoring ocean stratification changes. This project will further mature a technique to accurately observe low-mode internal tides using satellite altimetry. It will not only improve our understanding of internal tide activities, but also develop a new technique for monitoring ocean stratification, providing an independent long-term, low-cost, environmentally-friendly observing system. The global ocean is subject to changes as evidenced by frequent extreme weathers such as heat waves and tropical cyclones. Besides ocean warming and sea level rise, it is well-known that stratification intensification may change large-scale ocean circulations; one extreme scenario is shown in the movie “The Day After Tomorrow.” The satellite-derived internal tide models will be useful to the oceanographic community in designing field experiments, modeling internal tides, primary productivity, ocean acoustics, coral reef bleaching, ocean mixing, and internal tide correction. The new information on ocean stratification changes will be made freely available to researchers around the globe. This project will train a graduate student at the University of Washington. The team will also make an animation to simply explain the techniques to young kids and the public.Ocean stratification plays an important role in many dynamics processes including mass transport, isopycnal mixing and meridional ocean circulation. This project will investigate ocean stratification changes using satellite altimetry, the World Ocean Atlas, Argo floats, and two numerical models ECCO and HYCOM. Its goals are to (1) construct a global network utilizing long-range internal tide beams, (2) quantify seasonal cycle, decadal trend, and interannual variation of ocean stratification in terms of internal tide speed, (3) validate the satellite-derived ocean stratification changes with in situ measurements, and (4) evaluate the performance of ECCO and HYCOM in reproducing ocean stratification.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.