OceanBound

海洋之旅

• 批准号: NE/X01455X/1
• 负责人: Christopher Hughes
• 金额: $ 67.34万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX01455X%2F1
• 关键词: OceanBound

The currents in the ocean are turbulent, and dominated by "eddy variability" on scales much smaller than the ocean basins. This complex, nonlinear variability makes it impossible to understand the ocean as a whole in all its detail - we can run very expensive computer models at high resolution and get realistic-looking answers, but how do we know whether their long-term predictions are also realistic? That relies on having a good understanding of the processes involved - we have to find a way to sidestep the complications of the eddies and find comprehensible aspects of the system to connect the models, via theory, to the real ocean circulation. Fortunately, when we look at the "sidewall" boundaries of the ocean, we find that the eddy effects are greatly simplified, and we get a picture of the whole ocean which can be connected to theoretical ideas.The aim of this project is to make the global ocean circulation comprehensible in terms of a small number of clearly defined processes, and hence to improve understanding of its influence on a range of important issues from sea level to heat transport.Amidst the eddying chaos, there are parts of the ocean circulation which operate on a global scale, carrying water between different ocean basins and carrying heat around the world. These modes are among the most important parts of the global climate system. One mode is the Atlantic Meridional Overturning Circulation, which transports heat to the north throughout the entire Atlantic Ocean and has a large effect on European climate. Others include the Indonesian Throughflow, which carries warm water from the Pacific to the Indian Ocean, and the Antarctic Circumpolar Current, which connects the Atlantic, Indian and Pacific oceans. The currents associated with these modes have an influence on coastal sea levels around the world, causing sea level to be higher along some coasts than others. We call the effect of these modes the "global plumbing" of the ocean.Although we have computer models which can simulate many aspects of the ocean circulation well, it is hard to model how this plumbing varies over time. Making good predictions of future climate and sea level requires us to understand the causes of variability, and to test our understanding we need good measures of how the plumbing changed in the past.The ocean's turbulence makes it very hard to measure such large scale modes. To measure the currents themselves would require an enormous number of instruments to be in the ocean at all times. But we now know that pressure on the sidewalls of the ocean encodes information about the large scale modes without the added confusion from turbulence and eddies. Processes occurring at just a few places control the pressures, and therefore the plumbing, over very large distances.In this project, we will use ocean modelling to learn how those local processes influence ocean boundary pressures, and hence the global ocean plumbing. The new understanding will then be used to determine which future changes we can have confidence in, and to direct improvements of the next generation of climate models.

海洋中的洋流是湍流的，并且在比海洋盆地小得多的尺度上由“涡流变率”主导。这种复杂的、非线性的变化使得我们不可能从整体上了解海洋的所有细节--我们可以运行非常昂贵的高分辨率计算机模型，得到看起来很现实的答案，但我们如何知道它们的长期预测是否也是现实的呢？这依赖于对所涉及的过程有很好的理解--我们必须找到一种方法来避开漩涡的复杂性，并找到系统的可理解方面，通过理论将模型与真实的海洋环流联系起来。幸运的是，当我们观察海洋的“侧壁”边界时，我们发现涡流效应被大大简化，我们得到了一幅可以与理论思想联系起来的整个海洋的图片。这个项目的目的是使全球海洋环流可以用少量明确定义的过程来理解，从而提高对它对从海平面到热量输送等一系列重要问题的影响的理解。在混乱的漩涡中，有一部分海洋环流在全球范围内运作，在不同的海洋盆地之间输送水，并在世界各地输送热量。这些模态是全球气候系统中最重要的部分。一种模式是大西洋经向翻转环流，它将热量输送到整个大西洋的北部，对欧洲的气候有很大的影响。其他包括印度尼西亚洋流，它将温暖的水从太平洋带到印度洋，以及南极绕极流，它连接大西洋，印度洋和太平洋。与这些模式相关的海流对世界各地的沿海海平面产生影响，导致沿着某些海岸的海平面高于其他海岸。我们把这些模式的影响称为海洋的“全球管道”，虽然我们有计算机模型可以很好地模拟海洋环流的许多方面，但很难模拟这种管道如何随时间变化。要对未来气候和海平面做出准确的预测，我们需要了解变化的原因，为了检验我们的理解，我们需要对管道系统在过去是如何变化的进行良好的测量。海洋的湍流使得测量如此大规模的模式变得非常困难。要测量洋流本身，就需要大量的仪器一直在海洋中。但是我们现在知道，海洋侧壁上的压力编码了关于大尺度模式的信息，而没有湍流和漩涡的额外混乱。发生在几个地方的过程控制着压力，因此管道，在非常大的距离。在这个项目中，我们将使用海洋建模来了解这些局部过程如何影响海洋边界压力，从而影响全球海洋管道。新的认识将用于确定我们可以相信的未来变化，并指导下一代气候模型的改进。