非相干雷达探测低电离层的结果分析

位于波多黎各的Arecibo非相干雷达可以获得低电离层电子和离子密度, 利用此非相干雷达数据对中纬度低电离层的运动特征进行研究. 得到了电子密度随时间和高度的变化 情况, 结果显著呈现出周日变化特征, 并分析了电子密度随高度的变化规律. 进一步对数据进行频谱分析, 深入研究低电离层电子密度的周日变化效应. 得到电子密度的高度剖面, 发现从F层底部到E层有明显的等离子体沉降. 低电离层的层结构特征及电子密度变化表明, 在该区域还存在不同程度的等离子体扰动, 由此对低电离层的作用因素 进行分析, 认为大气潮汐或声重波可能对低电离层产生扰动, 即低电离层与大气存在一定程度的耦合作用. 

Analysis and Results from ISR Observations of Lower Ionosphere

The D and E regions lie in the lower ionosphere region of 60～110km height. This region is influenced by solar radiation, cosmic noise radiation, atmospheric electrodynamics and many factors, and there exists a variety of incredible variation characteristics. Even in the magnetically quiet day, atmospheric electrodynamics can make a significant effect on this region except solar radiation. In the D region, there exists radio waves strong absorption, which can influence the transmission of high frequency radio waves. Electron and ion density can be obtained from the Incoherent Scatter Radar (ISR) Arecibo, located at Puerto Rico. ISR data can be used to study the movement characteristics of the lower ionosphere in mid-latitude, and get the electron density curves changing with time and height, which present obvious diurnal changing phenomenon. The spectrum of the data is analyzed to probe diurnal effects of electron density changes. Besides the electron density height profiles have been drawn, and observe obvious plasma descending from the base of F-layer to E region. The layer structure characteristics of the lower ionosphere and electron density changing show that there exists different degree of disturbance. By analyzing the influencing factors it is concluded that the atmospheric tides and the acoustic gravity waves can cause disturbance to lower ionosphere, which is coupled with the atmosphere in certain degree.