Numerical Investigations of Currents, Eddy Kinetic Energy, and Internal-waves in the Southern Ocean

南大洋洋流、涡动能和内波的数值研究

• 批准号: 0525758
• 负责人: Jennifer MacKinnon
• 金额: --
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0525758&HistoricalAwards=false
• 关键词: Numerical; Investigations; Currents; Eddy; Kinetic

ABSTRACTOCE-0525758Intellectual Merit:Diapyncal mixing in the Southern Ocean (SO) plays a vital role in controlling the global over- turning circulation that redistributes heat, freshwater, and dissolved greenhouse gases throughout the world's oceans. The rate at which water masses are imported, transformed, and exported to the rest of the world are controlled by the Southern Ocean Meridional Overturning Circulation and several interior dynamics. However, the ACC represents the only oceanic instance of a zonally unbounded flow, and is therefore not subject to Sverdrup dynamics. Instead, all meridional transport of heat, freshwater, dissolved gases, and nutrients is accomplished through meridional flows. Many previous models of ACC dynamics have assumed that all water modification has occured at the surface while the surface water below has flowed northward or southward along isopycnal surfaces. However, a series of recent studies in the Southern Ocean has suggested that the diabatic fluxes from propagating internal-waves are too large to be ignored. In this study, a researcher at the University of California-San Diego Scripps Institution of Oceanography will investigate the relative importance of breaking energetic internal waves on the net meridional circulation in a zonally unbounded flow such as the ACC through a series of idealized numerical experiments. The experiments will impose an upward propagating field of internal waves, consistent with various models of wave generation, onto a realistic mean zonal flow and geostrophic eddy field. Based on previous and preliminary work, the waves will break due to a combination of intrinsic nonlinear dynamics, absorption into critical layers, and interaction with eddy vorticity. The rate of energy loss from propagating internal waves will determine the vertical structure of wave-breaking and the depth of associated meridional stresses and water mass modification. Broader Impacts:The results from this work will not only lead to a better understanding of the Meridional Overturning Circulation of the Southern Ocean but also improve the communities conceptual understanding and the accuracy of operational climate models. The circulation of the Southern Ocean plays an extremely important role in the earth's climate by regulating the global movement and storage of heat, freshwater, dissolved greenhouse gases, and biologically essential nutrients. Current global scale models may suffer from not appropriately including the diabatic forcing from breaking internal-waves in Southern Ocean dynamics. A dynamical understanding of the resultant geography of mixing is required for accurate understanding and modeling of the large-scale circulation in past, present and future climates. The immediate goal of this project is to develop a dynamical understanding that will allow appropriate parameterization of these effects to improve our conceptual understanding and the accuracy of operational climate models.

摘要-0525758学术成就：南大洋（SO）的层间混合在控制全球翻转环流中起着至关重要的作用，全球翻转环流将热量、淡水和溶解的温室气体重新分配到整个世界的海洋中。水团输入、转化和输出到世界其他地方的速率受南大洋经向翻转环流和几种内部动力学控制。 然而，ACC代表了唯一的海洋实例的纬向无界流，因此不受Sverdrup动力学。相反，所有热量、淡水、溶解气体和营养物质的纬向输送都是通过纬向流完成的。许多以前的ACC动力学模型都假设所有的水改性都发生在地表，而下面的地表水沿着沿着等密度面向北或向南流动。然而，最近在南大洋的一系列研究表明，传播的内波的非绝热通量太大，不能忽略。在这项研究中，加利福尼亚大学圣地亚哥斯克里普斯海洋研究所的研究人员将通过一系列理想化的数值实验，研究在纬向无界流（如ACC）中，在净纬向环流中破碎高能内波的相对重要性。实验将施加一个向上传播的内波场，符合波生成的各种模型，到一个现实的平均纬向流和地转涡场。根据以前的初步工作，波将打破，由于组合的内在非线性动力学，吸收到临界层，并与涡涡的相互作用。传播的内波的能量损失率将决定波浪破碎的垂直结构和相关的波浪应力和水体改变的深度。更广泛的影响：这项工作的结果不仅将导致更好地了解南大洋的经向翻转环流，而且还将提高社区对概念的理解和业务气候模型的准确性。南大洋的环流在地球气候中起着极其重要的作用，它调节着热量、淡水、溶解的温室气体和生物必需营养素的全球运动和储存。目前的全球尺度模式可能会遭受不适当的包括非绝热强迫打破南大洋动力学的内波。为了准确地理解和模拟过去、现在和未来气候中的大尺度环流，需要对混合的地理过程进行动态的了解。该项目的近期目标是发展一种动态的理解，以便对这些影响进行适当的参数化，从而提高我们对概念的理解和业务气候模型的准确性。