Collaborative Research: Eddy-Dynamics and Impacts of Low-Frequency Variations in the California Current System

合作研究：加州海流系统中的涡动力学和低频变化的影响

• 批准号: 0550233
• 负责人: Niklas Schneider
• 金额: $ 19.33万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0550233&HistoricalAwards=false
• 关键词: Collaborative; Research; Eddy; Dynamics; Impacts

The California Current System (CCS) is an eastern boundary region with a very high biological productivity adjacent to one of the main population centers of the United States. This project will test the hypothesis, suggested by recent observational investigations, that synoptic ocean eddies in the region play a major role in controlling its low frequency variations.. Specifically, the work will (i) study the impacts of intrinsic and externally forced mesoscale eddy variability on the inter-annual and decadal changes of temperature, salinity and currents in the CCS, (ii) diagnose the dynamics of the synoptic ocean response (the eddy field) to transient local atmospheric forcing and to remote oceanic forcing associated with El Nino and the adjustments of the North Pacific gyre, (iii) identify the patterns of tracer distribution from and to the coastal upwelling system and (iv) explore the response of the North East Pacific thermocline to variations in the CCS.The primary tools for these studies are high resolution, nested, ocean models (ROMS), augmented by their existing Adjoint and Tangent Linear codes. Model domains include the entire Pacific, to supply the large scale conditions, and regional nested areas of very high resolution in the CCS region. The regional simulations will selectively apply climatological or time dependent atmospheric and oceanic boundary conditions to isolate influences of ocean intrinsic variability, of atmospheric forcing and of remote ocean forcing. Of special note are the surface fresh water fluxes formulations, which will not use the unphysical feedback of surface relaxation to reference surface salinity. The comparison of these experiments will allow the identification of the impacts of the different forcing and the role of intrinsic ocean processes. Analysis of these runs will include (i) budget calculations for momentum, salinity and vorticity to determine the role of ocean synoptic variations in the low frequency changes of the CCS, (ii) EOFs and spectral analysis to statistically characterize the dynamical relationships in the budget terms and isolate the signature of oceanic processes, (iii) stability and sensitivity analysis with the tangent linear and adjoint models to diagnose the generating mechanisms and dynamics of the eddies during different circulation and forcing regimes and (iv) probability distribution functions for passive tracers to further clarify the stirring and mixing pathways from and to the upwelling system.Intellectual Merits: This study aims to increase understanding of the role and dynamics of ocean intrinsic variations of the eastern boundary regions, and their role in energizing and affecting the regional and large-scale low-frequency climate variations. This is essential to the understanding and prediction of the physics, chemistry and biology of these highly productive coastal upwelling systems. In particular this study will focus on the California Current coastal upwelling system, a major economical resource for US fisheries.Broader Impacts: The improvements in our ability to model observed long-term variability in the CCS will directly be available to a related NSF Long Term Ecological Research Site (LTER) sponsored program on Nonlinear Transitions in the California Current Coastal Pelagic Ecosystem at Scripps. Among the LTER tasks is the use of physical-biological models of the CCS to test hypothesis on ecosystem changes. The dynamical inferences on the changes eddy variance and mixing pathways, have direct application in the NSF-GLOBal Ecosystems studies (GLOBEC). The principal investigators communicate on a regular basis with some of the scientists involved in GLOBEC and will promptly share the results of this research. The investigator at the Georgia Institute of Technology will participate in K-12 educational outreach, to promote oceanography in a one day "hands on experience' for high school students during the summer camps activity organized by the Center for Education Integrating Science, Mathematics and Consulting (CEISMC). Two oceanography education sessions for 6th grade teacher from Fulton County, Atlanta, will also be held at Georgia Tech as part of this outreach activity.

加州洋流系统（CCS）是一个东部边界地区，生物生产力非常高，毗邻美国主要人口中心之一。该项目将检验最近的观测调查所提出的假设，即该区域的天气海洋涡旋在控制其低频变化方面起着主要作用。具体而言，这项工作将（i）研究内在和外在强迫的中尺度涡变对CCS中温度、盐度和海流的年际和年代际变化的影响，（ii）诊断天气海洋响应的动力学（涡动场）到瞬时局部大气强迫和与厄尔尼诺和北太平洋环流调整有关的远程海洋强迫，（iii）确定示踪剂分布的模式和沿海上升流系统和（iv）探讨东北太平洋温跃层的变化在CCS.The主要工具，这些研究是高分辨率，嵌套，海洋模式（ROMS），增加了现有的伴随和切线线性代码。模式域包括整个太平洋，以提供大规模的条件，并在CCS区域非常高的分辨率区域嵌套区。区域模拟将有选择地应用气候学或随时间变化的大气和海洋边界条件，以隔离海洋固有变化、大气强迫和远距离海洋强迫的影响。特别值得注意的是地表淡水通量公式，它将不使用非物理反馈的表面松弛参考表面盐度。这些实验的比较将有助于确定不同强迫的影响和内在海洋过程的作用。对这些试验的分析将包括：（一）动量、盐度和涡度的收支计算，以确定海洋天气变化在CCS低频变化中的作用;（二）EOFs和谱分析，以统计方式描述收支项中的动力学关系，并分离出海洋过程的特征;（iii）利用切线线性模式和伴随模式进行稳定性和敏感性分析，以诊断不同环流和强迫状况下涡旋的生成机制和动力学;被动示踪剂的概率分布函数，以进一步阐明上升流系统的搅动和混合路径。本研究旨在增加对东部边界区域海洋内在变化的作用和动力学的了解，以及它们在激发和影响区域和大尺度低频气候变化方面的作用。这对于理解和预测这些高产沿海上升流系统的物理、化学和生物学至关重要。特别是这项研究将集中在加州目前的沿海上升流系统，美国fisheres.Broader的经济资源：我们的能力，以模拟观察到的长期变化的CCS的改进将直接提供给相关的NSF长期生态研究网站（LTER）赞助的非线性过渡计划在加州目前的沿海远洋生态系统在斯克里普斯。长期接触试验的任务之一是使用CCS的物理-生物模型来检验关于生态系统变化的假设。涡度变化和混合途径的动力学推论，在全球生态系统研究（GLOBEC）中有直接的应用。主要研究人员定期与参与GLOBEC的一些科学家进行沟通，并将及时分享这项研究的结果。在技术的格鲁吉亚研究所的调查员将参加K-12教育推广，以促进海洋学在一天的“实践经验”的高中学生在夏令营活动由中心教育整合科学，数学和咨询（CEISMC）组织。作为这次推广活动的一部分，亚特兰大富尔顿县六年级教师的两次海洋学教育会议也将在格鲁吉亚理工学院举行。