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

最近的计算机模拟表明，在印度尼西亚和菲律宾群岛的盆地和海峡（珊瑚三角）的不同层之间的界面（内部潮汐）出现潮汐，随后各层混合。这些潮汐将太平洋的海水带到印度洋。尽管有计算机生成的结果，但该地区对内部潮汐和混合的直接测量很少。该项目将使用拉格朗日量（即沿着水平流动路径）测量温度、盐度和垂直剖面浮标的水流，以研究内波，特别是内潮的水平，以及它们通过垂直混合改变水性质的作用。该项目将使用来自菲律宾群岛的现有数据，以及在单独资助的（NSF）“印度尼西亚通流国际实验测量和建模”（MINTIE）中部署的额外新浮子。结果将用于评估该地区正在使用的计算机模式的内部潮汐和环流特征。该项目将支持国际（美澳）合作，并通过国家数据中心提供原始剖面和导出的内波和混合产品，促进电磁速度剖面数据的更广泛使用。该项目将为一个针对少数族裔的新APL-UW项目的本科生实习生提供项目材料。太平洋-印度洋通流路径的混合是全球热盐环流的关键水团转化步骤，对海表温度和海气相互作用具有一级影响。预测的内潮产生的位置很可能是混合热点，但辐射的内潮能量在哪里以及如何消散仍然是一个悬而未决的问题。这一提议将测试内部潮汐作为混合剂的主导地位。这些结果将用于评估用于测试该地区混合水平和分布的通流敏感性的数值模式的内部潮汐和环流特征。项目目标包括：1)描述菲律宾海和印度尼西亚海的内部潮汐振幅和辐射模式，以验证来源、日和半日贡献（包括各自的春季/小潮周期）和垂直波数结构；(2)限制内部潮汐参数化的参数，特别是辐射能量的比例和耗散的垂直结构；3)沿路水质量转化率评价；4)为EM-APEX剖面建立一个共享和公开的数据库，用于类似的研究和吸收分层和速度数据的海洋状态和预测系统。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.