Collaborative Research: Global Observational Constraints on Oceanic Response to Wind Forcing

负责在整个海洋表面边界层分布动量的物理过程是海洋学界积极关注的主题。这种兴趣在很大程度上是由于正确地将耦合气候模式中的上层海洋过程参数化的核心重要性。与此同时，海洋学中有一种传统，即通过研究风应力与观测到的表面流之间关系的性质来寻找物理信息。这项研究将有助于更好地理解在全球气候模式中准确地将海洋表面边界层参数化所需的混合过程，这是一项重要的社会效益。在考虑到风力强迫的情况下，估计表面流能力的任何改进，预计都将对溢油反应和其他实际应用感兴趣。该社区的一个关键输出将是对当地风力驱动的海流的改进估计，该估计将作为补充数据产品从全球漂流计划的网站上分发。该项目还将支持一名职业生涯初期的科学家。该项目的目标是通过第一次对风/流传递函数的全球研究，更好地了解海洋表面边界层的动力学。这将通过详细分析全球表面漂移器阵列对风强迫的响应来实现，这些漂移器对15米浮筒深度附近的洋流进行采样。全球分析的依据是：(1)来自上大洋区域研究区域的盐度过程的原型研究，该研究位于一个仪器齐全的海气通量系泊处附近；(2)对最近改进的湍流闭合模型产生的合成数据进行分析，该模型明确包括朗缪尔湍流。风、波浪和层结状态实质上改变近地表混合的假设将通过检查传递函数对各种环境参数的依赖性来检验，例如朗缪尔数。然后，将通过推导出表征不同混合过程的预期传递函数的新的理论近似来解释和仔细检查观察到的模式。

The physical processes responsible for distributing momentum throughout the ocean surface boundary layer are the subject of active concern in the oceanographic community. This interest is motivated to a large degree by the central importance of correctly parameterizing upper-ocean processes in coupled climate models. At the same time, there is a tradition in oceanography of seeking physical information by examining the nature of the relationship between wind stress and observed surface currents. This study will contribute to a better understanding of the mixing processes that are needed to accurately parameterize the ocean surface boundary layer in global climate models, an important societal benefit. Any improvement in the ability to estimate surface currents given the wind forcing is expected to be of interest for oil spill response and other practical applications. A key output for the community will be an improved estimate of the locally wind-driven currents, which will be distributed from the Global Drifter Program's website as a supplementary data product. This project will also support an early-career scientist.The goal of this project is to better understand the dynamics of the ocean surface boundary layer through the first global study of the wind/current transfer function. This is to be accomplished by analyzing in detail the response to wind forcing in the global array of surface drifters, which sample the ocean currents in the vicinity of their 15 m drogue depth. The global analysis is to be informed and tested by (i) a prototype study from the Salinity Processes in the Upper Ocean Regional Study region, near a well-instrumented air-sea flux mooring, and (ii) analysis of synthetic data generated with a recently improved turbulence closure model that explicitly includes Langmuir turbulence. The hypotheses that wind, wave, and stratification state substantially modify near-surface mixing will be tested by examining dependencies of the transfer function on various environmental parameters, such as Langmuir number. Observed patterns will then be interpreted and scrutinized by deriving new theoretical approximations to the expected transfer functions characterizing different mixing processes.