Collaborative Research: Microstructure and Mixing Measurements During SPURS

合作研究：SPURS 期间的微观结构和混合测量

• 批准号: 1129646
• 负责人: Raymond Schmitt
• 金额: $ 192.6万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129646&HistoricalAwards=false
• 关键词: Collaborative; Research; Microstructure; Mixing; Measurements

Surface salinity variations in the global ocean are caused by freshwater exchange with the atmosphere and land, via evaporation, precipitation and runoff. The expectation that the water cycle will accelerate with global warming has motivated an increased interest in upper-ocean salinity; since the water cycle is predominantly over the ocean, the sea-surface salinity may well be the very best indicator of changes in the water cycle. In considering such ocean-atmosphere interactions, areas of surface salinity extrema are of special interest. A multi-agency field program, the Salinity Processes Upper-ocean Regional Studies (SPURS), to begin to understand the oceanic processes that control upper ocean salinity will be executed in 2012-13. SPURS is focused on the surface salinity maximum in the eastern North Atlantic. The salinity of the upper ocean is controlled by surface freshwater exchange with the atmosphere, mixing and entrainment from below, and mean and eddy advection by horizontal currents, including those due to geostrophic, Ekman and smaller scales of motion. Other elements of SPURS will evaluate many of these processes; here we propose to focus on upper-ocean mixing. Microstructure sensors on profiling and gliding platforms will be used to quantify the mixing processes operating within the salinity maximum region. In addition, model simulations will elucidate both model quality and the physical processes important to the mixing and upper ocean stability structure. Intellectual Merit: Understanding and prediction of the evolution of the upper-ocean salinity field depends on accurate description and parameterization of the sub grid-scale mixing processes that dissipate the salinity variance created by surface water fluxes. Microstructure measurements will quantify the diabatic flux terms relevant to the temperature and salinity budgets being constrained by the overall SPURS study. The role of surface convection, internal wave processes, and double-diffusive mixing on these fluxes will be assessed. Model simulations, fed by the air-sea interaction buoy data, will help identify the source of the turbulence. Mixing parameterizations for double diffusion will be assessed through alteration of the model implementation to utilize diffusivities as taken from the microstructure based estimates. The combined approach of microstructure measurements and modeling is the most efficient route to provide information that could lead to improved parameterizations. The impact will be multiplied by the synergistic effects of being incorporated into the overall SPURS program, where observations and models of basin, regional and the mesoscale will be undertaken. Broader Impacts: Improved understanding of ocean mixing processes are essential for advancing climate science, as the representation of sub grid-scale processes in large-scale models continues to be a major unresolved issue. The focus of this project on the salinity is especially relevant to documenting change in the global water cycle, which has tremendous implications for society. As part of this project the investigators will maintain web sites on SPURS and the mixing processes operant in the salinity maximum region. To enhance educational outreach, the investigators will collaborate with The Zephyr Education Foundation's innovative marine science literacy and education program, located in Woods Hole. The Zephyr Foundation is ideally suited for this purpose and attracts school groups from Massachusetts and Rhode Island, including underrepresented and disadvantaged students from inner-city programs in Boston and New Bedford. This project will also involve active roles for full-time graduate students at WHOI/MIT. In addition, a modeling and data analysis module suitable for distribution will be produced.

全球海洋表面盐度的变化是由蒸发、降水和径流与大气和陆地的淡水交换引起的。 人们对水循环将随着全球变暖而加速的预期激发了人们对上层海洋盐度的兴趣增加。由于水循环主要发生在海洋上，因此海面盐度很可能是水循环变化的最佳指标。 在考虑这种海洋-大气相互作用时，表面盐度极值区域特别令人感兴趣。 一项多机构实地计划，即盐度过程上层海洋区域研究 (SPURS)，旨在开始了解控制上层海洋盐度的海洋过程，将于 2012-13 年执行。 SPURS 重点关注北大西洋东部的表面盐度最大值。 上层海洋的盐度受表面淡水与大气交换、来自下方的混合和夹带以及水平流产生的平均和平流平流（包括地转流、埃克曼流和较小尺度运动引起的流）的控制。 SPURS 的其他要素将评估其中的许多流程；在这里，我们建议重点关注上层海洋的混合。 剖面和滑翔平台上的微结构传感器将用于量化在盐度最大区域内运行的混合过程。 此外，模型模拟将阐明模型质量和对混合和上层海洋稳定结构很重要的物理过程。 智力优点：对上层海洋盐度场演变的理解和预测取决于对次网格尺度混合过程的准确描述和参数化，这些过程消除了地表水通量产生的盐度变化。 微观结构测量将量化与受整体 SPURS 研究限制的温度和盐度预算相关的非绝热通量项。 将评估表面对流、内波过程和双扩散混合对这些通量的作用。 由海气相互作用浮标数据提供的模型模拟将有助于识别湍流的来源。 双扩散的混合参数化将通过改变模型实现来评估，以利用从基于微观结构的估计中获取的扩散率。 微观结构测量和建模的组合方法是提供可改进参数化信息的最有效途径。 纳入整个 SPURS 计划的协同效应将使其影响倍增，该计划将进行盆地、区域和中尺度的观测和模型。 更广泛的影响：提高对海洋混合过程的理解对于推进气候科学至关重要，因为大规模模型中次网格尺度过程的表示仍然是一个未解决的主要问题。 该项目的重点是盐度，这与记录全球水循环的变化尤其相关，这对社会产生巨大影响。 作为该项目的一部分，研究人员将维护 SPURS 网站以及在盐度最大区域运行的混合过程。 为了扩大教育范围，研究人员将与 Zephyr 教育基金会位于伍兹霍尔的创新海洋科学素养和教育项目合作。 Zephyr 基金会非常适合此目的，吸引了来自马萨诸塞州和罗德岛州的学校团体，其中包括来自波士顿和新贝德福德市中心项目的代表性不足和弱势的学生。 该项目还将让 WHOI/MIT 的全日制研究生发挥积极作用。 此外，还将制作适合分发的建模和数据分析模块。