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

这项工作的智力价值涉及澄清海洋边界附近的独特动力学和量化它们对基本海洋过程的影响，如边界应力，中尺度耗散和绝热等密度线扩散的diapycnal混合。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，这是本项目的主要重点，目前正在处理湾流的地形控制问题，特别是湾流分离问题。这个项目是建立在这样一个假设之上的，即边界对一般的海洋环流，特别是墨西哥湾流施加基本的控制。这些过程在目前的气候模式中表现得很差或不存在。拟议研究的主要重点是惯性重力波的次惯性激发和边界过程激活次中尺度，着眼于其潜在的涡度和横向应力的影响。驱动假说是，这些过程主导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，所有现有的模型都在努力解决，无论分辨率如何。其结果是在北大西洋模式中引入了很强的偏差，这可能会影响十年时间尺度上的气候预测。观测还表明，地形在促进混合方面发挥着重要作用。更广泛的影响：为气候变化做好准备是目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海洋部分的一个重大缺陷。中尺度流和边界流是海洋的主要运动学特征，在所有现有模式中均由参数化控制。该项目旨在将边界相互作用的物理模型纳入这些参数化，从而提高气候预测的准确性，消除目前海洋环流模型中存在的一个重大偏差。由于新的参数化将在共同体气候系统模型中实施，因此将广泛提供给一般气候界。

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.