Source of High Trace-Velocity Infrasound Signals and Pulsating Auroras

高痕速次声信号和脉动极光的来源

• 批准号: 0741641
• 负责人: Hans Nielsen
• 金额: $ 40.41万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0741641&HistoricalAwards=false
• 关键词: Source; Trace; Velocity; Infrasound; Signals

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.

该项目调查次声阵列观测到的高迹线速度信号与极光之间的可能联系，并设法确定信号的来源。 这项研究的起源是2004年发现的高跟踪速度次声信号，似乎是由脉动极光引起的。 一个相对较大的“高迹速事件”数据，现在似乎很清楚，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事件，但有许多夜晚有广泛的脉动极光显示，但没有显示次声信号的迹象。 然而，似乎确实与地磁活动水平有关，因为许多事件发生在当地地面磁力计记录的活动高峰期。 尚未查明造成这些信号的物理过程，对电离层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性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，并确定信号的可能电离层来源。 目前有一个大型次声数据集，将由次声阵列观察到的其他事件补充;数据采集和分析通过一个单独的方案提供资金。 一个重要的新数据元将由目前位于阿拉斯加扑克坪研究靶场的高级模块化非相干散射雷达提供。 AMISR可提供详细的电离层时空信息，有助于确定次声信号的来源。 该项目还将为阿拉斯加大学地球物理研究所极光摄像机的继续运行提供资金，该摄像机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，该项目还将进行一项补充性研究，研究能量转换为大气声波的机制以及在何种条件下发生能量转换。 该项目更广泛的影响包括支持一名研究生，该研究生将接受数据获取和硬件、大气和电离层动态和过程以及大型数据集的操纵、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实际大气中的传播。