Collaborative research: Deep eastern ocean boundary currents from local submesoscale potential vorticity dynamics to global climate implications

在所有南半球海洋盆地的观测研究中，不断出现大量深层东边界流的证据。这些向极流的核心携带着纬向翻转环流的重要组成部分。这些深极流发生在一些地区以及下涌系统的特点是赤道表面电流和极向暗流。 这些流动影响南大洋的水团结构，是深层环流的重要组成部分。然而，它们的动态并没有得到很好的理解，它们在气候模型中要么表现得很差，要么根本没有表现出来。 这项研究将是首次尝试了解深东部边界流的动态及其对气候模拟和预测的后果。该项目包括培训两名研究生，一名博士后研究员，并通过万维网向公众宣传。该项目使用各种观测分析，贝叶斯逆模型和高分辨率区域海洋模型研究深层东部边界流。 高分辨率海洋模式可以解决中尺度和亚中尺度涡动过程，可能参与这些深边界流的位涡动力学。反演模式和高分辨率区域海洋模式的结果将用于建立理想化的理论模式，并用于了解深层东部边界流。拟议中的研究还将审查模拟的深东部边界流在全球耦合模式，其不良的模拟气候模式的后果？大尺度动力学和未来气候预测。 虽然在上升流系统中，深层东部边界流与上层海洋暗流完全不同，但这项研究将受益于对这种暗流所做的工作，有助于确定相关的动力过程。其中包括：β效应、风旋度、底坡、产生和消散Rossby波的次中尺度涡旋、涡旋-地形相互作用、上升梯度涡旋动量通量、位涡入流条件、次中尺度涡旋和垂直混合过程引起的位涡输送和混合、次中尺度和准地转中尺度涡旋对深层层结的影响以及与地形有关的内部纬向洋流对深层东部边界流的影响。

Evidence for substantial deep eastern boundary currents emerges repeatedly from observational studies in all southern hemisphere ocean basins. The core of these poleward flows carries a significant component of the meridional overturning circulation. These deep poleward flows occur in some areas well beneath upwelling systems characterized by an equatorward surface current and a poleward undercurrent. These flows affect the Southern Ocean water mass configuration and are an important part of the deep general circulation. Yet their dynamics are not well understood, and they are either poorly represented or not represented at all in climate models. This study will be the first attempt to understand the dynamics of deep eastern boundary currents and their consequences to climate simulation and projections. The project includes training of two graduate students, one postdoctoral researcher, and outreach to the public via the World Wide Web.This project studies deep eastern boundary currents using an analysis of varied observations, a Bayesian inverse model, and a high resolution regional ocean model. The high resolution ocean model can resolve mesoscale and submesoscale eddy processes that may participate in the potential vorticity dynamics of these deep boundary currents. The results of the inverse model and high resolution regional ocean model will be used to develop an idealized theoretical model and understanding of deep eastern boundary currents. The proposed study will also examine the simulation of deep eastern boundary currents in global coupled models, and the consequences of their poor simulation on the climate models? large scale dynamics and future climate projections. While deep eastern boundary currents are completely distinct from upper-ocean undercurrents in upwelling systems, this study will benefit from work done on such undercurrents, helping identify relevant dynamical processes. These include: beta effect, wind curl, bottom slope, submesoscale eddies generating and dissipating Rossby waves, eddy-topography interactions, up-gradient eddy momentum fluxes, potential vorticity inflow conditions, potential vorticity transport and mixing by submesoscale eddies and by vertical mixing processes, submesoscale and quasi-geostrophic mesoscale eddy effects on the deep stratification, and interior topography-related zonal ocean flows feeding deep eastern boundary currents.