CEDAR: Comprehensive Use of Incoherent Scatter Radar Data to Study the Equatorial Midnight Plasma and Neutral Temperature Maxima (MTM)

CEDAR：综合利用非相干散射雷达数据研究赤道午夜等离子体和中性温度最大值（MTM）

• 批准号: 0836452
• 负责人: Carlos Martinis
• 金额: $ 31.7万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0836452&HistoricalAwards=false
• 关键词: CEDAR; Comprehensive; Use; Incoherent; Scatter

This project will investigate the midnight temperature maximum (MTM), an enhancement of the neutral temperature (Tn) of roughly 50-200 K in the nighttime equatorial thermosphere. The phenomenon is created by the convergence of air near midnight at low latitudes. Current physics-based numerical models are not able to reproduce the MTM phenomenon with the amplitudes commonly observed. The implication of this inability indicates that the ion-neutral coupling between the low-latitude F-region plasma and the thermosphere and the influence of tidal forcing from below are not well understood. This project will investigate the MTM feature using ion temperature data obtained with Incoherent Scatter Radars (ISRs) from the CEDAR, Madrigal, and local databases. Specifically, since the MTM is an equatorial process, emphasis is placed on MTM characterization using data from the low-latitude Arecibo and Jicamarca ISRs. The ISR MTM will be characterized in terms of amplitude, time of occurrence, and temporal duration. A preliminary count indicates that there are ~400 days of Arecibo and Jicamarca data available for the study, distributed in a way that will allow the determination of seasonal and solar activity variations of the MTM. A ground-based climatology of MTM occurrence has been obtained with Fabry-Perot interferometers (FPIs) at Arequipa, but this climatology does not include the austral summer months (November to early March) due to cloudy conditions. The current project fills this gap with ISR ion temperature data from Jicamarca and expands the climatology to Arecibo's latitude. FPIs provide height-integrated optical information and so provide no information on the height dependence of the MTM. Radars, on the other hand, do provide results as a function of altitude. A systematic study of the height dependence of the MTM is one of the main goals of this project. Knowledge of this height dependence is crucial to any attempt to model, for example, the height penetration of tidal modes, so, as an additional goal, model comparisons of MTM characteristics will be carried out. An additional objective is the comparison of the radar data with optical (FPI and all-sky imager) and digisonde data available at Arecibo and near Jicamarca. This effort provides the first multi-diagnostic study of the MTM. All-sky imager data at El Leoncito (31.8 S) and Millstone Hill ISR (42.6 N) data will be used to study the latitudinal extent of the equatorial MTM phenomenon. The scientific question addressed in this project is: can a multi-diagnostic approach established around the temporal, altitudinal and latitudinal information provided by ISRs improve our knowledge of the MTM?

该项目将研究午夜温度最高（MTM），这是夜间赤道热层中大约50-200 K的中性温度（TN）的增强。这种现象是由于低纬度午夜附近的空气收敛而产生的。当前基于物理的数值模型无法使用通常观察到的幅度来重现MTM现象。这种无能的含义表明，低纬度F-Region等离子体与热圈之间的离子中性耦合以及从下方的潮汐强迫的影响尚不清楚。该项目将使用从Cedar，Madrigal和本地数据库获得的离子温度数据研究MTM特征。具体而言，由于MTM是赤道过程，因此使用低纬度Arecibo和Jicamarca ISRS的数据将MTM表征放在MTM表征上。 ISR MTM将以幅度，发生时间和时间持续时间来表征。初步计数表明，可用于研究的Arecibo和Jicamarca数据有约400天，以允许确定MTM的季节性和太阳活动变化的方式分布。在Arequipa的Fabry-Perot干涉仪（FPI）获得了MTM发生的基于地面的气候，但是由于阴云状况，这种气候不包括澳大利亚夏季（11月至3月初）。当前的项目通过JICAMARCA的ISR离子温度数据填补了这一空白，并将气候扩展到Arecibo的纬度。 FPI提供高度集成的光学信息，因此没有提供有关MTM高度依赖性的信息。另一方面，雷达确实提供了结果的函数。对MTM的高度依赖性的系统研究是该项目的主要目标之一。对这种高度依赖性的了解对于任何尝试建模的尝试，例如潮汐模式的高度渗透至关重要，因此，作为一个附加目标，将进行MTM特性的模型比较。另一个目标是将雷达数据与光学（FPI和All-Sky Imager）和Digisonde数据进行比较，可在Arecibo和Jicamarca附近提供。这项工作提供了MTM的首次多诊断研究。 El Leoncito（31.8 s）和Millstone Hill ISR（42.6 N）数据的所有天空成像仪数据将用于研究赤道MTM现象的纬度范围。该项目中解决的科学问题是：ISRS提供的时间，高度和纬度信息围绕时间，高度和纬度信息建立的多诊断方法可以改善我们对MTM的了解吗？