Collaborative Research: Isopycnal Spectra and Stirring on the Submesoscale and Finescale in the Upper Ocean

合作研究：上层海洋亚介尺度和细尺度的等密度光谱和搅拌

• 批准号: 1734222
• 负责人: Eric Kunze
• 金额: $ 32.82万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1734222&HistoricalAwards=false
• 关键词: Collaborative; Research; Isopycnal; Spectra; Stirring

Lateral stirring is among the primary processes, along with advection and diapycnal mixing, that determines the distribution and fate of water-mass properties, nutrients and dissolved gases in the upper ocean. Ocean general circulation models resolve stirring on scales larger than thirty kilometers, and regional models on scales close to one kilometer, but isopycnal stirring by unresolved submesoscale processes must still be parameterized. Novel high-resolution observations in the sub-tropical Pacific Ocean will provide insight into the underlying physics and how these processes operate in the upper ocean in order to improve such parameterizations for eddy-resolving ocean circulation models. Results should be applicable to the submesoscale in other rotating stratified fluids such as the atmosphere of Earth, stars and gas giants that occupy the same parameter space. A post-doctoral fellow will be trained in interpretation of data in the rapidly emerging field of oceanic submesoscales. Two graduate students will have an opportunity to participate in sea-going research.Order one Rossby number and gradient Richardson number sub-inertial flows have emerged as an area of ocean parameter space that is incompletely understood but becoming accessible to observations, modelling and theory. The kinematics and dynamics of isopycnal stirring on length scales shorter than the Rossby deformation length of order 100 kilometer and longer than outer turbulence scales of order one meter do not have a well-established theoretical underpinning because of the paucity of observational constraints. At scales shorter than the Rossby length scale, quasigeostrophic (QG) theory predicts that tracers should have a spectrum of slope of minus one [corresponding to tracer-gradient spectra with slope plus one]. This contrasts with numerous observations spanning the horizontal horizontal wavelengths 30 m to 500 km which report significantly redder and often almost flat tracer-gradient spectra over this wavenumber band. Similar dynamical comparisons are in short supply. High resolution sections of the upper 150 meter of the ocean will be sampled using a towed chain with tightly spaced temperature, conductivity and pressure (CTD) sensors and the shipboard Acoustic Doppler Current Profiler (ADCP). This project will characterize the horizontal wavenumber spectra of passive tracers (water-mass, spice, salinity anomalies) on isopycnals to higher horizontal wavenumbers than previously accomplished, and resolve the sub-inertial O(1 km) horizontal strain tensor thought responsible for stirring on these scales, as well as determine strain timescales. These measurements will provide key observational constraints on order one Rossby number and Richardson number flows.

横向搅拌是主要过程之一，与平流和纵向混合一起，决定了上层海洋中水团性质、营养物质和溶解气体的分布和命运。海洋环流模式在大于30公里的尺度上解决了搅拌问题，区域模式在接近1公里的尺度上解决了搅拌问题，但未解决的亚中尺度过程的等平流层搅拌仍然必须参数化。在亚热带太平洋进行的新的高分辨率观测将提供对底层物理和这些过程如何在上层海洋中运作的深入了解，以便改进涡旋解析海洋环流模式的参数化。结果也适用于其他旋转分层流体的亚中尺度，如地球大气、恒星和气体巨星等，它们占据相同的参数空间。将培训一名博士后如何解释迅速兴起的海洋亚中尺度领域的数据。两名研究生将有机会参加航海研究。一阶罗斯比数和梯度理查德森数亚惯性流已经成为海洋参数空间的一个区域，虽然还不完全了解，但已经可以通过观测、建模和理论来实现。由于缺乏观测约束，短于100公里量级的罗斯比形变长度和长于1米量级的外湍流尺度的等压搅拌的运动学和动力学没有一个完善的理论基础。在小于罗斯比长度尺度的尺度上，准等转（QG）理论预测示踪剂的光谱斜率应为- 1[对应于斜率为+ 1的示踪剂梯度光谱]。这与跨越30米至500公里水平波长的许多观测结果形成对比，这些观测结果在该波数波段上报告了显着更红且通常几乎是平坦的示踪梯度光谱。类似的动态比较很少。将使用带有紧密间隔的温度、电导率和压力（CTD）传感器的拖曳链和船载声学多普勒电流分析器（ADCP）对海洋上方150米的高分辨率部分进行采样。该项目将在等斜线上对被动示踪剂（水质量、盐盐异常）的水平波数谱进行表征，使其达到比以前更高的水平波数，并解决被认为负责在这些尺度上搅拌的亚惯性O（1公里）水平应变张量，以及确定应变时间尺度。这些测量将提供一阶罗斯比数和理查德森数流的关键观测约束。

项目成果

Two-Dimensional Wavenumber Spectra on the Horizontal Submesoscale and Vertical Finescale

水平亚介尺度和垂直细尺度的二维波数谱

• DOI: 10.1175/jpo-d-21-0111.1
• 发表时间: 2022
• 期刊: Journal of physical oceanography
• 影响因子: 3.5
• 作者: Vladoiu, A.;Lien, R.-C.;Kunze, E.
• 通讯作者: Kunze, E.

A Unified Model Spectrum for Anisotropic Stratified and Isotropic Turbulence in the Ocean and Atmosphere

海洋和大气中各向异性层状和各向同性湍流的统一模型谱

• DOI: 10.1175/jpo-d-18-0092.1
• 发表时间: 2019
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: Kunze, Eric