Mixing in the Indonesian Throughflow: Analysis of Lagrangian observations of shear, watermass modification, and internal wave climates

印度尼西亚贯穿流中的混合：拉格朗日切变观测、水团修改和内波气候的分析

• 批准号: 2219987
• 负责人: James Girton
• 金额: $ 48.28万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2219987&HistoricalAwards=false
• 关键词: Mixing; Indonesian; Throughflow; Analysis; Lagrangian

Recent computer simulations have suggested the appearance of tides at the interfaces between different layers (internal tides) in the basins and straits of the Indonesian and Philippine Archipelagos (the Coral Triangle), with subsequent mixing of the layers. These tides carry and transform waters from the Pacific on their path to the Indian Ocean. Despite the computer-generated results, direct measurements of internal tides and mixing have been scarce in this region. This project will use Lagrangian (i.e., following the horizontal flow pathway) measurements of temperature, salinity, and currents from vertically profiling floats to investigate the levels of internal waves, especially internal tides, and their role in transforming water properties through vertical mixing. The project will use existing data from the Philippines Archipelago, along with additional new float deployments in the separately funded (NSF) "Measuring and Modeling the INdonesian Throughflow International Experiment" (MINTIE). Results will be used to evaluate the internal tide and circulation characteristics of computer models being used in the region. The project will support an international (US–Australia) collaboration and facilitate the broader use of electromagnetic velocity profiler data by providing raw profiles and derived internal wave and mixing products through national data centers. The project will furnish project material for undergraduate interns in a new APL-UW program targeting minorities.Mixing along the Pacific-to-Indian Ocean throughflow pathway is a key water mass transformation step in the global thermohaline circulation and has a first-order influence on sea-surface temperature and air–sea interaction. The locations of predicted internal tide generation are very likely to be mixing hot spots, but it remains an open question where and how the radiated internal tide energy is dissipated. This proposal will test the dominance of internal tides as mixing agents. The results will be used to evaluate the internal tide and circulation characteristics of numerical models being used to test throughflow sensitivity to the level and distribution of mixing in the region. Project's goals include: 1) the description of internal tide amplitude and radiation patterns in both the Philippine and Indonesian Seas to verify sources, diurnal and semidiurnal contributions (including the spring/neap cycle of each), and vertical wavenumber structure; 2) constraining the parameters appropriate to internal tide parameterizations, especially the fraction of energy radiated and the vertical structure of the resulting dissipation; 3) evaluation of along-path water mass transformation rates; 4) establishing a shared and publicly available database for EM-APEX profiles, of use for research studies like this one and ocean state and forecast systems assimilating stratification and velocity data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

最近的计算机模拟表明，在印度尼西亚和菲律宾群岛（珊瑚三角区）的盆地和海峡中，不同层（内潮）之间的界面处出现了潮汐，随后各层混合。这些潮汐将太平洋的沃茨带到印度洋，并将其转化。尽管有计算机生成的结果，但在这一地区，对内潮和混合的直接测量很少。该项目将使用拉格朗日（即，沿着水平流动路径）测量温度、盐度和来自垂直剖面浮标的水流，以研究内波（尤其是内潮）的水平及其在通过垂直混合改变水性质中的作用。该项目将使用菲律宾群岛的现有数据，沿着在单独资助的（NSF）“测量和模拟印度尼西亚洋流国际实验”（MINTIE）中额外部署的新浮标。研究结果将用于评估该区域使用的计算机模型的内潮和环流特征。该项目将支持国际（美国-澳大利亚）合作，并通过国家数据中心提供原始剖面和衍生的内波和混合产品，促进更广泛地使用电磁速度剖面仪数据。该项目将提供一个新的APL-UW计划针对少数民族的本科实习生的项目材料。混合沿着太平洋到印度洋的通流路径是一个关键的水团转换步骤在全球温盐环流和海表温度和海气相互作用的一阶影响。预测的内潮产生的位置很可能是混合热点，但它仍然是一个悬而未决的问题，辐射内潮能量是如何耗散的。这一建议将测试内潮作为混合剂的优势。这些结果将用于评估数值模型的内潮和环流特征，这些模型用于测试通流对该区域混合水平和分布的敏感性。项目的目标包括：1）描述菲律宾海和印度尼西亚海的内潮振幅和辐射模式，以验证来源、日和半日贡献（2）限制适合于内潮参数化的参数，特别是辐射能量的份额和由此产生的耗散的垂直结构; 3）沿程水团转化率的估算; 4）建立一个共享的和公开可用的EM-APEX概况数据库，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。