Type I - Collaborative Research: Topographic Control of the Gulf Stream

这项工作的学术价值包括澄清海洋边界附近的独特动力学及其对基本海洋过程的影响，如边界应力、中尺度耗散和绝热等日混合以及绝热等日弥散。物理海洋学中尚未解决的主要动力学问题涉及西部边界流的“耗散”闭合，这是该项目的主要焦点。正在解决墨西哥湾流地形控制及其分离的具体应用问题。这个项目是建立在这样一个假设之上的，即边界对大洋环流，特别是墨西哥湾流施加基本控制。这些过程在当前的气候模型中没有得到很好的表现，或者根本不存在。拟研究的重点是惯性重力波的亚惯性激发和边界过程对次中尺度的激活，以期了解它们的潜在涡度和侧向应力影响。驱动假设是，这些过程主导着墨西哥湾流分离和下游发展。这是海洋环流的一个关键方面，所有当前的模型都在努力解决这个问题，无论分辨率如何。其结果是在北大西洋模式中引入了强烈的偏差，这可能会影响十年时间尺度上的气候预测。观察还表明，地形在促进混合方面发挥了重要作用。广泛的影响：为气候变化做好准备是当前社会面临的最紧迫的问题。该项目正在解决耦合气候模型中海洋部分的一个重大缺陷。中尺度和边界流是海洋的主要运动学特征，在所有现有的模式中都是通过参数化来控制的。该项目旨在将边界相互作用的物理模型纳入这些参数，从而提高气候预测的精确度，并消除当前海洋环流模型中发现的主要偏差。由于新的参数化将在社区气候系统模式中实施，它们将广泛适用于一般气候社区。

The intellectual merits of this work involve clarification of the unique dynamics near oceanic boundaries and quantification of their effects on essential oceanic processes like boundary stress, mesoscale dissipation and diapycnal mixing followed by adiabatic isopycnal dispersion. The primary unsolved dynamical problem of physical oceanography involves the 'dissipative' closure of western boundary currents, which is the primary focus of this project.The problem of Topographic Control of the Gulf Stream with particular application to its separation is being addressed. This project is built on the hypothesis that boundaries exert fundamental controls on the ocean circulation in general and the Gulf Stream in particular. These processes are poorly represented or absent from current climate models. The main focus of the proposed research is on sub-inertial excitation of inertia-gravity waves and activation of the sub-mesoscale by boundary processes, with a view towards their potential vorticity and lateral stress implications. The driving hypothesis is that these processes dominate Gulf Stream separation and downstream development. This is a critical aspect of ocean circulation that all current models struggle with, regardless of resolution. The result is the introduction of strong biases in the model North Atlantic that is likely to affect climate projection on the decadal time scale. Observations also suggest an important role for topography in promoting mixing.Broader impacts: Preparing for climate change is the most pressing problem currently facing society. This project is addressing a significant shortcoming of the oceanic component of coupled climate models. The mesoscale and boundary currents are the dominant kinematic features of the ocean and are controlled in all existing models by parameterizations. This project is designed to build into these parameterizations physically based models of boundary interactions, thereby enhancing the fidelity of climate prediction and eliminating a major bias found in current ocean circulation models. Since the new parameterizations will be implemented in the Community Climate System Model, they will be widely available to the general climate community.