Collaborative Research: Evolution and Fate of Eighteen Degree Water in the North Atlantic Subtropical Gyre

合作研究：北大西洋副热带环流十八度水的演化和命运

• 批准号: 0961090
• 负责人: Young-Oh Kwon
• 金额: $ 107.36万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961090&HistoricalAwards=false
• 关键词: Collaborative; Research; Evolution; Fate; Eighteen

This project will examine the physical processes associated with the evolution (formation, circulation, and destruction) of Eighteen Degree Water (EDW) within the subtropical gyre of the North Atlantic Ocean. EDW is the archetype for the anomalously thick and vertically homogenous mode waters that are typical of all subtropical western boundary current systems. EDW is associated with a shallow overturning circulation that carries heat northward and is an interannual reservoir of anomalous heat, nutrients and CO2. Understanding the annual cycle of EDW evolution, and in particular its associated circulation pathways and destruction mechanisms, is important because though EDW is isolated beneath the stratified upper-ocean at the end of each winter, it may reemerge in subsequent years to influence mixed layer properties and consequently air-sea interaction and primary productivity.The pathways of EDW circulation, the processes of EDW destruction, and the role of EDW in modulating ocean-atmosphere heat exchange and nutrient supply to the euphotic zone will be investigated. The plan is to synthesize a broad spectrum of observations including a substantial in-situ dataset collected during the recently completed CLIVAR Mode Water Dynamics Experiment (CLIMODE). This coordinated field effort included a large array of profiling floats, a moored array, and several hydrographic surveys. To supplement this unique dataset the investigators will also examine contemporary and historical hydrography, Argo profiling floats, surface drifters, satellite altimetry and ocean color fields, and output from several eddy-resolving OGCM simulations.Intellectual Merit: This project will test the long-hypothesized climatic importance of EDW as an element of the North Atlantic's shallow overturning circulation and as a short-term reservoir of heat, nutrients, and carbon. Significantly, this study will advance understanding of the various processes that destroy EDW. In addition, this study will, for the first time, compare and contrast the roles of the large-scale, low-frequency circulation and the mesoscale eddy field in EDW dispersal and destruction. Finally, the proposed work will provide a foundation for comparative studies since mode waters are found in every ocean basin.Broader Impacts: Clarifying the role of EDW in the exchange of heat between the atmosphere and ocean will support ongoing community efforts to improve interannual-to-decadal predictability. For example, EDW and its associated air-sea heat flux may have a direct impact on the year-to-year variability of surface storm amplitude in the North Atlantic storm track near the Gulf Stream. In addition, understanding the role of EDW in the storage and exchange of nutrients will advance our understanding of interannual variability in primary productivity. Rigorous model-data comparisons using the unique CLIMODE dataset will also aid the broader community by providing an objective assessment of the fidelity of eddy-resolving numerical models. Finally, the project will support the training of two postdoctoral investigators and a graduate student.This project is a contribution to the U.S. CLIVAR (CLImate VARiability and predictability) program.

该项目将研究与北大西洋亚热带循环中18度水（EDW）相关的物理过程（形成，循环和破坏）。 EDW是异常厚和垂直均匀模式的原型，这些水是所有亚热带西部边界电流系统中典型的典型特征。 EDW与浅倾覆的循环有关，该循环向北传递热量，是异常热，营养和二氧化碳的年际水库。了解EDW进化的年度周期，尤其是其相关的循环途径和破坏机制，这一点很重要，因为尽管EDW在每个冬季结束时都隔离在分层的上圆形下，但随后的几年可能会重新出现，以影响混合层的性质因此，将研究EDW循环的途径，EDW破坏的过程以及EDW在调节海洋 - 大气热交换中的作用以及向兴奋区调节养分供应的作用。该计划是综合广泛的观察结果，包括在最近完成的Clivar Mode Water Dynamics实验（山峰）期间收集的实物内数据集。这种协调的现场工作包括大量的分析浮子，停泊的阵列和几项水文调查。为了补充这个独特的数据集，调查人员还将检查现代和历史水文图，Argo分析浮子，表面漂移器，卫星高度计和海洋色领域，并从几个涡流解决的OGCM仿真中输出。智能优点：该项目将测试长期化的项目。 EDW作为北大西洋浅倾覆的循环的重要性，也是热，营养和碳的短期储层。重要的是，这项研究将提高人们对破坏EDW的各种过程的理解。此外，这项研究将首次比较和对比大规模，低频循环和EDW分散和破坏中的中尺度涡流的作用。最后，拟议的工作将为比较研究提供基础，因为在每个海洋盆地中都发现了模式水。 - 婚姻可预测性。例如，EDW及其相关的空气热通量可能会直接影响海湾流附近北大西洋风暴轨道的地面风暴幅度的年度变异性。此外，了解EDW在养分储存和交换中的作用将提高我们对初级生产率际变化的理解。使用独特的攀登数据集进行严格的模型数据比较，还将通过对涡流数值模型的忠诚度进行客观评估，以帮助更广泛的社区。最后，该项目将支持对两名博士后调查人员和一名研究生的培训。该项目是对美国Clivar（气候变异性和可预测性）计划的贡献。