Collaborative Research: Finite Amplitude Gravity Wave Trains in the Upper Mesosphere - Lower Thermosphere Duct System: Build Up and Leakage of Energy from Local and Distant Sources

合作研究：上层中间层-下层热层管道系统中的有限振幅重力波列：来自本地和远程源的能量积累和泄漏

• 批准号: 1344350
• 负责人: Richard Walterscheid
• 金额: $ 16.5万
• 依托单位: Aerospace Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1344350&HistoricalAwards=false
• 关键词: Collaborative; Research; Finite; Amplitude; Gravity

Earth's mesosphere and lower thermosphere (MLT) contain thermal and wind structures that can support a large population of ducted waves that are confined to localized regions where conditions support their existence and propagation. Often, waves can travel simultaneously in multiple ducts. Distinctive aspects of these waves are that they may grow to large amplitudes, travel large distances horizontally and induce changes far from their sources. Waves ducted in two ducts simultaneously may carry much greater energy over larger distances than waves confined to a single duct. There is a growing body of evidence that large-amplitude ducted waves are associated with frequent occurrences of extensive changes in the MLT. Ducted waves may affect broader regions of the atmosphere than non-ducted waves since the former may transfer energy horizontally over long distances prior to dissipation. Even weak or partial ducting may cause a significant redistribution of wave energy. Ducted waves provide a mechanism for prolific wave sources such as in low-latitude convective zones. The processes by which waves may attain large amplitudes, transfer energy from distant sources and produce effects in the MLT where the waves become untrapped need to be better understood and better characterized to help improve our understanding of the wave control of the MLT. Such a characterization would be the basis for improved parameterization schemes of wave drag for general circulation models. This investigation is a theoretical study supported by data analysis to address outstanding questions concerning the role of ducted waves in the MLT. The specific objectives are to assess the buildup of wave energy in MLT ducts and the propagation and leakage of energy from ducts under realistic MLT conditions. The study will use theory, numerical modeling, and comparisons to observations of ducted waves from an extensive data base of ducted quasi-monochromatic wave events. Data will be obtained from airglow imagers, lidar and radar from diverse locations (Andes Lidar Observatory, Maui, Adelaide, and Alice Springs) and from the SABER instrument on the TIMED satellite. The research focuses on a largely unexplored mechanism for effecting the global redistribution of wave energy in the mesospheric and lower-thermospheric ducting system. The work will establish that ducts populated by prolific wave sources in the lower atmosphere are of considerable geophysical importance far from the source regions. The results will lead to the development of modeling capabilities for investigating ducting as a means of wave growth and the redistribution of wave energy between regions of the atmosphere, both vertically and horizontally. It will support coordinated multi-instrument investigations at existing sites, and provide a continuing research opportunity for a female scientist and a graduate student.

地球的中层和下热层（MLT）包含热量和风结构，这些热结构和风结构可以支撑大量的管道波，这些波浪仅限于局部区域，这些区域支持其存在和传播。通常，波浪可以同时在多个管道中传播。这些波浪的独特方面是它们可能生长到大幅度，水平行进大距离，并引起远离源头的变化。同时在两个管道中导管的波浪在更大的距离上可能具有比局限于单个管道的波更大的能量。越来越多的证据表明，大振幅导管波与MLT发生巨大变化的频繁发生有关。导管波可能会影响大气的宽区域，而不是非管道的波浪，因为前者可能会在耗散前的长距离内水平转移能量。即使是弱或部分管道也可能导致波能重新分布。管道波为多产波源（例如低纬度对流区域）提供了一种机制。波浪可能获得大幅度，从远处传递能量并在MLT中产生效果的过程，在该过程中需要更好地理解波浪，并且需要更好地理解和更好地表征，以帮助我们提高对MLT波控制的理解。这种表征将是一般循环模型的波浪阻力参数化方案的基础。这项研究是一项由数据分析支持的理论研究，旨在解决有关MLT导管的作用的杰出问题。具体目标是评估MLT管道中波能的积累，以及在现实的MLT条件下从导管中传播和泄漏。该研究将使用理论，数值建模和比较与从管道单式波波事件的广泛数据库中对管道波的观察进行比较。数据将从来自不同位置的气流成像仪，激光雷达和雷达（安第斯山脉天文台，毛伊岛，阿德莱德和爱丽丝弹簧）以及定时卫星上的Saber仪器中获得。该研究重点是在很大程度上未开发的机制，用于影响中层和低层管道系统中波能的全局重新分布。这项工作将确定在低大气中被多产波源所填充的管道具有很大的地球物理重要性。结果将导致建模能力的发展，以研究管道作为波长的一种手段，并在垂直和水平的大气区域之间的波能重新分布。 它将支持现有站点的协调多仪器调查，并为女科学家和研究生提供持续的研究机会。