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

地球的中间层和低热层（MLT）包含热和风结构，可以支持大量的管道波，这些管道波局限于条件支持其存在和传播的局部区域。通常，波可以同时在多个管道中传播。这些波的独特之处在于，它们可能会增长到很大的振幅，水平传播很长的距离，并引起远离其来源的变化。在两个管道中同时输送的波可以在更大的距离上携带比被限制在单个管道中的波大得多的能量。越来越多的证据表明，大振幅导管波与MLT频繁发生的广泛变化有关。管道波可能比非管道波影响更广泛的大气区域，因为前者可能在耗散之前将能量水平转移很长一段距离。即使是弱的或部分的管道也可能引起波能的显著重新分布。管道波提供了一种机制，如在低纬度对流区的多产波源。需要更好地理解和更好地表征波浪可能获得大振幅、从远距离源转移能量并在MLT中产生效应的过程，以帮助提高我们对MLT波浪控制的理解。这种特性将是改进大气环流模式波阻参数化方案的基础。这项调查是一个理论研究的数据分析支持，以解决悬而未决的问题，管道波在MLT的作用。具体目标是评估MLT管道中波能的积累以及实际MLT条件下管道能量的传播和泄漏。这项研究将使用理论，数值模拟，并比较从管道准单色波事件的广泛数据库的管道波的观测。将从不同地点（安第斯山脉激光雷达观测站、毛伊岛、阿德莱德和爱丽丝泉）的气辉成像仪、激光雷达和雷达以及TIMED卫星上的SABER仪器获取数据。研究的重点是一个在很大程度上尚未探索的机制，影响全球重新分配波能在中层和低热层管道系统。这项工作将确定，管道人口丰富的波源在低层大气中是相当重要的地球物理远离源区域。结果将导致发展的建模能力，调查管道作为一种手段，波的增长和波能之间的大气区域，垂直和水平的重新分配。 它将支持在现有地点进行协调的多仪器调查，并为一名女科学家和一名研究生提供继续研究的机会。

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.