Source of High Trace-Velocity Infrasound Signals and Pulsating Auroras

该项目调查次声阵列观测到的高速度信号与极光的可能联系，并试图确定这些信号的来源。这项拟议研究的起源是2004年发现的高轨迹速度次声信号，似乎是由脉动的极光引起的。现在看来，脉动极光可能不是这种信号的唯一来源：虽然在脉动极光期间观察到了事件，但有许多夜晚大量显示脉动极光，但没有显示出次声信号的迹象。然而，这似乎确实与地磁活动的水平有关，因为根据当地地面磁力计的记录，许多事件发生在活动高峰期。目前还没有确定产生这些信号的物理过程，对电离层来源的声波传播也没有很好的了解。该项目将结合极光、光学和磁学数据分析次声数据集，以确定和量化观测参数之间的任何关系，并查明这些信号的可能电离层来源。目前有一个庞大的次声数据集，将由次声阵列观测到的其他事件补充；数据采集和分析由一个单独的方案提供资金。一个重要的新数据元素将由目前位于阿拉斯加扑克平原研究靶场的先进模块化非相干散射雷达(阿米西里雷达)提供。阿米西可提供详细的空间和时间电离层信息，这可能有助于确定次声信号的一个或多个来源。该项目还将为阿拉斯加大学地球物理研究所的极光摄像机的继续运作提供资金，这将提供有关极光动力学的有用信息。除了分析和解释次声信号外，该项目还将对能量可转化为大气声波的机制以及在什么条件下发生能量转移进行补充研究。该项目的更广泛影响包括支助一名研究生，该研究生将接受数据采集和硬件、大气层和电离层动力学和过程以及大型数据集的处理、分析和解释方面的培训。该项目将使人们能够更好地了解电离层过程和声波在现实大气中的传播。

This project investigates the possible association of high trace-velocity signals, observed by infrasound arrays, with the aurora and seeks to establish the sources of the signals. The origin of the proposed study is a 2004 discovery of high trace velocity infrasound signals that appeared to be caused by pulsating aurora. A relatively large data of "high trace-velocity events" and it now seems clear that pulsating aurora may not be the sole source of such signals: while events are observed during pulsating aurora, there are many nights with extensive displays of pulsating aurora but show no signs of the infrasound signals. However, there does seem to be a connection with the level of geomagnetic activity, since many events occurred during times of high activity as recorded by local ground-based magnetometers. No physical process has yet been identified for the cause of these signals and there is not good understanding of the acoustic wave propagation from ionospheric sources. The project will analyze the infrasound data set in conjunction with auroral optical and magnetic data to establish and quantify any relationships between the observed parameters and to identify possible ionospheric sources for the signals. A large infrasonic data set is currently available, which will be complemented by additional events observed by infrasonic arrays; that data acquisition and analysis are funded through a separate program. An important new data element will be provided by the Advanced Modular Incoherent Scatter Radar (AMISR) currently located at Poker Flat Research Range, Alaska. AMISR can provide detailed spatial and temporal ionospheric information which may help in the identification of the source or sources of the infrasound signals. The project will also provide funding for the continued operation of the auroral video camera at the University of Alaska's Geophysical Institute which will provide useful information on auroral dynamics. In addition to the analysis and interpretation of the infrasound signals, the project will undertake a complementary study on the mechanisms by which energy can be transferred into atmospheric acoustic waves and under what conditions the energy transfer occurs. The broader impacts of the project includes the support of a graduate student who will receive training in data acquisition and hardware, atmospheric and ionospheric dynamics and processes, and manipulation, analysis, and interpretation of large data sets. The project will enable improved understanding of ionospheric processes and acoustic wave propagation in realistic atmospheres.