Collaborative Research: Three-dimensional structure of Arctic tides and near-inertial oscillations, and their role in changing the Arctic Ocean and ice pack

合作研究：北冰洋潮汐和近惯性振荡的三维结构及其在改变北冰洋和冰层中的作用

• 批准号: 1708289
• 负责人: An Nguyen
• 金额: $ 29.79万
• 依托单位: University of Texas at Austin
• 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: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708289&HistoricalAwards=false
• 关键词: Collaborative; Research; Three; dimensional; structure

The Arctic Ocean is undergoing rapid change. Implications are significant for strategic and tactical military planning; regional, and perhaps global, climate; northern ecosystems and cultures; and economic interests. Climate models qualitatively agree that these changes will persist. Projections of when specific benchmarks, such as an ice-free summer Arctic Ocean, will be reached vary by several decades. Reducing uncertainty in Arctic change projections is an important task. This project identifies tides and near-inertial (NI) waves, with periods of approximately 12 hours, as the major components of Arctic ocean velocity fields, mixing rates and ice dynamics that are not presently represented in global coupled climate models. The project will provide the Arctic community with a database of time-dependent tidal and NI energy in select current meter records. Also, it will provide a carefully-validated, high-resolution, fully-forced Arctic coupled ocean/sea-ice model (OIM) for quantifying the effects of high-frequency (HF) processes on seasonal and longer-term variability of the Arctic Ocean and its ice pack. The project will contribute to STEM workforce development through support for the training of a post-doctoral associate and a graduate student, and through support for two early-career scientists. K-12 outreach will be enabled through in-person and webinar programs at schools in AK, TX, WA and OR. A public-friendly video with visualization of model results will be prepared and distributed to schools and other communities including coastal Alaskan villages, and highlighted on the project website.Motivated by observations of strong HF ocean currents and ice drift velocities that are very sensitive tochanges in sea-ice state, sparse measurements of HF time series of ocean mixing and ice deformation,and coarse-grid models with parameterized tide forcing, this project tests the following hypothesis: "Energetic, HF processes, including tides and wind-generated NI waves, are critical contributors to the seasonal cycle and longer-term trends of the Arctic's 3-D hydrography and circulation, sea-ice characteristics, and exchanges of heat, freshwater and momentum between the atmosphere, ocean and sea-ice." The program's specific goals are to map the time-dependent distribution of HF energy in the ocean and ice throughout the Arctic; assess the role of HF processes in the Arctic ice and upper ocean; develop understanding of the HF processes coupling the sea ice, ocean, and atmosphere; and quantify the effect of HF processes on seasonal cycles and longer-term trends. Taking advantage of rapidly growing databases for ocean and sea-ice velocities, and improvements in resolution and physical realism of OIMs, it integrates analyses of tidal and NI signals in select Arctic ocean moorings and sea-ice drift data, validation of a high resolution (~2 km x 106 vertical levels) pan-Arctic OIM with full atmospheric and tidal forcing, and comparison of a suite of model simulations with different forcing to identify dominant HF processes. Simulations with simplified forcing (e.g., removing tides and low-pass filtering the winds to reduce NI forcing) will identify key factors involved in HF influence on ocean and sea-ice state on seasonal and longer time scales. Focus areas include the effect of HF processes on ice formation and dispersion of river freshwater and heat fluxes in shelf seas, on mixing of Atlantic- and Pacific-sourced waters along the Arctic continental slopes, on feedbacks between ocean and sea-ice HF processes, and on the seasonal cycle of atmospheric heat exchange with the ocean and sea ice.

北极海正在迅速变化。对战略和战术军事规划的影响很重要；区域，也许是全球气候；北部生态系统和文化；和经济利益。气候模型定性同意这些变化将持续存在。几十年来，何时达到特定基准（例如无冰夏季海洋）的预测将有所不同。减少北极变化预测的不确定性是一项重要任务。该项目确定潮汐和近惯性（Ni）波（大约12小时）是北极海洋速度场的主要组成部分，混合速率和冰动力学目前在全球耦合气候模型中尚未代表。该项目将为北极社区提供有关当前电表记录中时间依赖的潮汐和NI能量数据库。此外，它将提供精心验证的高分辨率，完全磨难的北极耦合海洋/海冰模型（OIM），以量化高频（HF）过程对北极海洋季节性和长期变化的影响。该项目将通过支持培训博士后同学和研究生，并通过支持两位早期职业科学家来为STEM劳动力发展做出贡献。 K-12外展活动将通过在德克萨斯州，华盛顿州AK和OR的学校的面对面和网络研讨会计划启用。 A public-friendly video with visualization of model results will be prepared and distributed to schools and other communities including coastal Alaskan villages, and highlighted on the project website.Motivated by observations of strong HF ocean currents and ice drift velocities that are very sensitive tochanges in sea-ice state, sparse measurements of HF time series of ocean mixing and ice deformation,and coarse-grid models with parameterized tide forcing, this project tests以下假设是：“北极3-D水文和循环，海冰特征，海冰特征以及热量，淡水，淡水，淡水和动量之间的交流，大气层和海洋之间的交流。该计划的具体目标是绘制整个北极的海洋和冰中HF能量的时间依赖性分布；评估HF过程在北极冰和上海中的作用；发展对海冰，海洋和气氛结合的HF过程的理解；并量化HF过程对季节性周期和长期趋势的影响。 Taking advantage of rapidly growing databases for ocean and sea-ice velocities, and improvements in resolution and physical realism of OIMs, it integrates analyses of tidal and NI signals in select Arctic ocean moorings and sea-ice drift data, validation of a high resolution (~2 km x 106 vertical levels) pan-Arctic OIM with full atmospheric and tidal forcing, and comparison of a suite of model simulations with different forcing确定主要的HF过程。具有简化强迫的模拟（例如，去除潮汐和低通滤波以减少Ni强迫）将确定涉及HF对海洋和海冰对季节性和更长时间尺度上的海洋和海冰状态影响的关键因素。焦点区域包括HF过程对货架海中河淡水和热通量的分散的影响，对北极大陆斜坡沿着大西洋和太平洋水的混合，对海洋和海冰HF工艺之间的反馈，以及与海洋和海洋冰的季节性热交换。