Lagrangian Mapping and Modeling of Thermohaline Intrusions in the Subtropical Front

温盐入侵在整个海洋中都能观察到，但它们在锋面附近最为突出。据估计，热、盐和浮力的横向扩散系数与斜压不稳定和中尺度涡旋产生的扩散系数一样大，但是。。。目前的知识不足以可靠地预测温盐的结构、长度尺度和横向通量(Ruddick和Richards，2003)。在通过海上观测更好地了解它们的基本结构和现象学之前，入侵及其通量不能在大尺度或区域模型中真实地表示出来。在这项研究中，华盛顿大学的研究人员将对北太平洋副热带锋面的入侵进行密集测量和高分辨率建模。这项研究的目的是在2D剖面和3D模式中确定侵入体的长度尺度和斜率，将侵入体长度尺度、斜率和构造与前方联系起来，并在可控中性浮子周围的拉格朗日框架内跟踪几个侵入体的演化，并推断它们的横向通量。如果可能，研究小组将确定产生和修改入侵的过程，并开发高分辨率模型，再现入侵形成和增长的基本方面。长期以来，对这些测量和建模的需求一直是显而易见的，但直到最近几年，所有必要的工具才变得可用。这包括具有向上和向下ADCP的深度循环拖体、微结构剖面仪、可命令的中性浮力拉格朗日浮子和灵活的高分辨率数值代码。虽然不是所有关于热盐侵入的问题都可以通过这项工作得到解决，但这项研究的结果将促进我们对副热带锋面侵入结构的理解，并为一些侵入如何演化提供进一步的洞察。除了这项工作的智力价值外，这项研究还将为研究生和博士后提供支持和培训。

Thermohaline intrusions are observed throughout the ocean, but they are most prominent near fronts. Lateral diffusivities of heat, salt and perhaps buoyancy are estimated to be as large as those produced by baroclinic instabilities and mesoscale eddies, but . . . present knowledge is insufficient to predict the structure, length-scales and lateral fluxes of thermohalines with confidence (Ruddick and Richards, 2003). Until their basic structure and phenomenology are better understood by observations at sea, intrusions and their fluxes cannot be represented realistically in large-scale or regional models. In this study, researchers at the University of Washington will take intensive measurements and perform high-resolution modeling of the intrusions in the N. Pacific subtropical front. The goals of this research are to determine the length scales and slopes of the intrusions in 2D sections and in 3D patterns, relate intrusion length scales, slopes and structures to the front, and follow the evolution of several intrusions in a Lagrangian frame around a commandable neutrally-buoyant float and infer their lateral fluxes. If possible, the team of researchers will identify the processes producing and modifying the intrusions, and develop high-resolution models that reproduce essential aspects of intrusion formation and growth. The need for measurements and modeling like these has long been apparent, but only during the last few years have all of the necessary tools become available. This includes a depth-cycling towed body with upward and downward ADCPs, microstructure profilers, and a commandable neutrally buoyant Lagrangian float, and flexible high-resolution numerical code. Though not all issues regarding thermoahaline intrusions can be solved from this work, the results gathered from this research will advance our understanding of the structure of the intrusions in the subtropical front, and provide further insight into how some of the intrusions evolve. In addition to the intellectual merit of the work, this research will provide the support and training of a graduate students and a postdoc.