电离层中小尺度扰动的多频多普勒快速探测与分析  

Multi-frequency Doppler Fast Detection and Analysis of Meso-micro Scale Ionospheric Disturbances

作　　者：贺德江 朱正平[1] 蓝加平[1] 宁百齐[2] 胡连欢[2] 

机构地区：[1]中南民族大学电子信息工程学院,武汉430074 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《空间科学学报》2017年第2期158-167,共10页Chinese Journal of Space Science

基　　金：国家自然科学基金项目资助(41474135;41127003;41134120)

摘　　要：电离层反射回波的高频多普勒频移测量是研究电离层扰动的重要方法之一.利用基于单频信号相位变化率测量的实时探测方法,获取连续高精度多频多普勒频高图,以实现中小尺度电离层扰动的快速探测研究.该方法被应用于敏捷式高性能电离层无线电多频探测系统样机平台.经验证在该平台上获取的多普勒频移分辨率可达0.039 Hz,频高图探测周期最短小于1 min.基于这种快速探测方法和平台在武汉观测站进行了较长时间的观测和数据采集,获得高精度多普勒频移并反演出电子浓度等值面法向运动速度,得到电离层反射寻常波的多普勒频高图和垂直扰动速度等信息,进而推演出电离层扰动随时间和空间的实时变化特征.对这些时域信号进行频谱分析,初步结果显示这些扰动主要是由极区活动激发的中国中部地区冬季出现率较高的中尺度TID.此外,对三种常用的电离层扰动反演分析方法进行了对比研究,结果显示电离层扰动的变化趋势基本一致,说明观测数据和研究方法可靠稳定,为多频多点电离层扰动的传播特性观测研究提供了基础.Measuring the HF Doppler frequency shifts of ionospheric echoes is one of the important ways to study ionospheric disturbances.We use the real-time detection method based on measuring the phase-change rate of single frequency signals,and obtain continuous high-precision multifrequency Doppler ionograms to achieve fast detection and study of meso-micro scale ionospheric disturbances.This method is applied to the multi-frequency detection system which is jointly developed by the Chinese Academy of Sciences and South-Central University for Nationalities.It is verified that the Doppler resolution obtained from this platform can be up to 0.039 Hz and the minimum ionogram period is less than 1 minute.We collect a long-time raw data of the ionosphere based on this new detection method and platform in Wuhan observatory.Through the way of acquiring high-precision Doppler frequency shifts and the method of inversing the normal velocity of electron concentration isosurface,the Doppler ionograms and vertical disturbed velocity of 0 waves are obtained.Furthermore,the real-time changes of ionospheric disturbances with time and space are deduced.By the spectrum analysis on these time domain signals,preliminary results show that these disturbances are mainly mesoscale TIDs motivated by the Polar activities which often appear in winter in central China.This paper also compares the three commonly used inversion methods.The results show that the ionospheric disturbances have almost the same change trends.It indicates that the observation data and the research methods are reliable and staljle,which provides an important basis for observing and researching the multi-frequency and multi-point propagation characteristics of ionospheric disturbances.

关 键 词：电离层中小尺度扰动 快速探测 多频探测系统 多普勒频移 电子浓度等值面法向运动速度 

分 类 号：P352.7[天文地球—空间物理学]