Air-sea exchanges at the ocean mesoscale: a driver of the ocean circulation?

海洋中尺度的海气交换：海洋环流的驱动因素？

• 批准号: 1790162
• 金额: --
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1790162
• 关键词: Air; sea; exchanges; ocean; mesoscale

Exchanges of heat, water and momentum at the air-sea interface are key to understanding, both oceanic and atmospheric circulations, and their representation in models is crucial to a range of issues: from short-range weather prediction (through an effect on the Atmospheric Boundary Layer (ABL)) up to the climate scale (e.g. intense localized air-sea fluxes in the North Atlantic couple the Gulf Stream and Meridional Overturning Circulation to the atmosphere).Air-sea interactions on the ocean-basin scale (1000s of km) have been extensively investigated. With the increasing quality of satellite observations of winds and Sea Surface Temperature (SST), it has become apparent that vigorous air-sea interactions also occur on the scale of ocean mesoscale eddies (50-100 km). Ocean eddies populate the global ocean, with thousands of them found at anytime. Observations show that the ABL adjusts to the large SST anomalies associated with ocean eddies. Although details of the adjustment mechanism are still debated, it appears that mesoscale SST anomalies modulate the intensity of the turbulent mixing and modify the strength of the surface winds (i.e. air-sea fluxes of momentum). For example, warm core eddies are associated with a more intense turbulent mixing and stronger surface winds. Through this mechanism, the ocean imprints its turbulent structure onto the global marine ABL and drives a rich atmospheric variability on scales of 100's km.Air-sea interactions at the ocean mesoscale are a new frontier in our understanding of the coupled system. Up to now, most studies of the Eddy-ABL interaction have focused on the quasi-linear relationship between SST and wind(-stress) anomalies and impacts on the atmospheric circulation. Impacts on oceans have received much less attention. The goal of the proposed work is to understand and to quantify the impact of the Eddy-ABL interaction on the ocean state: is it a fundamental mechanism that needs to be accounted for in the analysis and design of climate models?The new high-resolution coupled simulation (ORCA012/N512) developed at the Met Office offers a fantastic opportunity to investigate this topic. Preliminary analysis showed that the model captures the SST-wind relationship with the observed intensity, providing a solid basis to explore new ground.In this PhD project, the student will 1) Quantify the effect of oceanic eddies on air-sea fluxes of heat and moisture, 2) Clarify the mechanisms and quantify the impact on the ocean circulation, and 3) develop and test a parameterization of the Eddy-ABL interaction for models where it is absent.

在空气接口处的热量，水和动量交换是理解海洋和大气循环的关键，并且它们在模型中的代表对一系列问题至关重要：从短期天气预测（通过对大气边界层（ABL）的影响（ABL）的影响到气候量表到气候范围（例如，在北端的沿北部循环中，以及对北部的循环循环，都有在北端的循环中，并且是对北部的循环流动。大气）。已经广泛研究了海洋巴蛋白量表（1000 km）上的空气 - 海洋相互作用。随着风和海面温度（SST）的卫星观测质量的提高，很明显，海洋中尺度涡流（50-100 km）也发生了剧烈的空气相互作用。海洋涡流遍布全球海洋，随时发现了数千个。观察结果表明，ABL适应与海洋涡流相关的大型SST异常。尽管调整机制的细节仍在辩论中，但似乎中尺度的SST异常调节湍流混合的强度并改变了表面风的强度（即动量的空气海量磁通量）。例如，温暖的核心涡流与更强烈的湍流混合和更强的表面风有关。通过这种机制，海洋将其湍流结构烙印到全球海洋ABL上，并在海洋中尺度上的100 km.air-sea相互作用的尺度上驱动了丰富的大气变异性，这是我们对耦合系统的理解的新边界。到目前为止，大多数对涡流相互作用的研究都集中在SST和风（压力）异常之间的准线性关系以及对大气循环的影响。对海洋的影响较少。拟议工作的目的是了解和量化涡流互动对海洋状态的影响：这是在气候模型的分析和设计中需要考虑的基本机制吗？在气候模型的分析和设计中，新的高分辨率耦合模拟（ORCA012/N512）在MET办公室开发了一个绝佳的机会来研究这个主题。初步分析表明，该模型捕获了与观察到的强度的SST风关系，为探索新的基础提供了良好的基础。在该博士学位项目中，学生将量化海洋涡流对热量和水分的海洋通量的影响，2）澄清和量化对海洋循环的机制，并量化了对海洋循环的影响，并在其中进行了3）的影响。