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1.
In the first part of study the possibility of high frequency (HF) and low frequency (LF) modes of magnetogravity waves (MGW) propagation in the equatorial atmosphere in conditions of ionospheric F2 layer is demonstrated taking into account the finite conductivity. Here the spectral features of the excited HF MGW mode is studied. At the second part of study the dispersion relations for LF MGW in the ionospheric equatorial region is received. The spectral features of the disturbed components of medium displacement for LF MGW generated by a mass source are investigated. The results are applied to calculate the values of the spectral components of magnetogravity density, pressure and magnetic field disturbances caused by horizontal meteor sweep. The estimates may be useful in the analysis of ionospheric disturbances excited by high-energy geophysical sources. 相似文献
2.
A. V. Medvedev K. G. Ratovsky M. V. Tolstikov D. S. Kushnarev 《Geomagnetism and Aeronomy》2009,49(6):775-785
The method for studying the spatial-temporal structure and propagation characteristics of traveling ionospheric disturbances,
using the spectral and cross-correlation analysis of electron density disturbances at different altitudes, obtained with the
incoherent scatter radar and vertical sounding ionosonde, is considered. Different algorithms for detecting traveling ionospheric
disturbances and calculating the total vector of the disturbance propagation velocity are presented. The results of the method
application have been considered in detail, using September 11, 2005, as an example. 相似文献
3.
本文通过观测实例探讨并论证了电离层高频多普勒观测在扩展-F研究中的应用.实例和相应分析表明:首先,由于高频多普勒记录的时间连续性,有利于从观测角度了解扩展-F的时间演化过程;其次,高频多普勒偏移对不规则结构造成的回波弥散、对不同尺度行进电离层扰动(TID)以及耀斑引起的突然频率偏移(SFD)效应都很敏感,这些现象在记录上出现的时间关系有利于了解扩展-F的触发因素或扩展-F与其他电离层背景扰动之间的联系或相互作用;最后,高频多普勒记录对于持续时间较长(几小时以上)或很短(小于1小时)的扩展-F都能够完整地反映,不会产生因为观测间歇形成的缺失,也可以有效区分究竟是连续一次还是一段时间内断续的扩展-F现象.高频多普勒观测有其自身的优点同时也具有一定的局限性,本文对其局限性诸如缺乏空间分辨率等也做了分析.指出发挥高频多普勒观测的优势,综合应用多种资料,通过不同手段的数据分析和比较,可以更好地为电离层扰动的物理机制和预报研究提供正确的观测依据. 相似文献
4.
用数字测高仪漂移测量研究电离层声重波扰动 总被引：8，自引：1，他引：8
数字测高仪Digisonde中的漂移测量,常用来研究小尺度电离层扰动,如电离层小不均匀体的漂移。文中提出一种新的分析方法,利用漂移测量数据中多普勒频移和到达角参量的最大熵动态功率谱,估算声重波一类大尺度电离层扰动的水平传播速度和传播方向。作为实例,研究了Millstone Hill测高仪站的漂移观测资料,并对处理结果进行了初步分析。分析结果表明,从数字测高仪漂移测量数据中,可有效地提取声重波一类大尺度电离层扰动的传播参量,在电离层动力过程的研究中很有意义。 相似文献
5.
D. V. Blagoveshchenskii 《Geomagnetism and Aeronomy》2013,53(4):409-423
The manifestations of the so-called main ionospheric effect during geomagnetic storms (substorms) in the character of decameter-wave propagation are analyzed. On HF radio paths, the main effect is observed as variations in the signal amplitude and the MOF-LOF working frequency band similarly to the critical frequency of the ionospheric F2 layer. Specifically, these parameters increase before the disturbance active phase, decrease during the active phase, and increase again after this phase. The propagation outside the great circle arc, the change in the propagation processes, and the HF radio noise behavior were also considered on these paths during storms (substorms). It is assumed that the storm (substorm) development onset can be predicted. 相似文献
6.
T. D. Borisova N. F. Blagoveshchenskaya I. M. Ivanova M. T. Rietveld 《Geomagnetism and Aeronomy》2013,53(1):32-42
The interaction between the Earth’s ionosphere and magnetosphere in a situation when artificial disturbances are generated in the F region of the auroral ionosphere with the EISCAT/Heating facility is studied. An experiment was performed in the daytime when the facility effective radiated power changed in a stepwise manner. Wavelike disturbances with periods of (130–140) s corresponding to Pc4 pulsations were simultaneously registered by the method of bi-static backscatter and with ground magnetometers. The variations in the Doppler frequency shift were correlated with the changes in the facility power. Incoherent scatter radar measurements at a frequency of 930 MHz (Tromsö) and numerical calculations were used in an analysis. It has been indicated that the ionospheric drift of small-scale artificial ionospheric irregularities was modulated by magnetospheric Alfvén waves. The possible effect of powerful HF radioemission on the Alfvén wave amplitude owing to the modification of the magnetospheric resonator ionospheric edge reflectivity and the generation of an outgoing Alfvén wave above the region where the ionospheric conductivity is locally intensified has been considered. 相似文献
7.
电离层声重波扰动的高频无线电诊断 总被引：1，自引：1，他引：1
为了充分发挥现代数字式电离层探测仪在电离层结构与优动研究中的潜力,必须在传统的频高图真高换算的基础上,发展新的反演理论和算法.本文介绍了随时空缓变的各向异性电离层介质中无线电波包传播的广义射线方程组,讨论了计算波包射线几何路径以及计算波包参数,如频移、波矢、群时延等沿射线路径变化的传播正问题,并详细讨论了根据波包参量的测定值反演介质结构和扰动伏态的传播反问题.文中若干实验实例表明,这种反演理论和算法可用于数字式电离层探测仪记录的分析,它使高频无线电波探测技术成为研究全球电离层声重波一类扰动的有力工具。 相似文献
8.
D. V. Blagoveshchenskii 《Geomagnetism and Aeronomy》2016,56(4):448-456
We analyze ionospheric oblique sounding data on three high-latitude and one high-latitude–midlatitude HF radio paths for February 15 and 16, 2014, when two substorms and one magnetic storm occurred. We investigate cases of anomalous propagation of signals: their reflection from sporadic layer Es, lateral reflections, type “M” or “N” modes, the presence of traveling ionospheric disturbances, and the diffusivity of signals and triplets. The most significant results are the following. In geomagnetically undisturbed times, sporadic Es-layers with reduced maximum observed frequencies (MOFEs) on three high-latitude paths were observed in both days. The values of MOFEs during disturbances are large, which leads to the screening of other oblique sounding signals reflected from the ionosphere. On all four paths, the most frequently traveling ionospheric disturbances due to the terminator were observed in quiet hours from 03:00 to 15:00 UT on the first day and from 06:00 to 13:00 UT on the second day of the experiment. In addition, both the sunset terminator and the magnetic storm on the high-latitude–mid-latitude path were found to generate traveling ionospheric disturbances jointly. No such phenomenon was found on high-latitude paths. 相似文献
9.
Seismoionospheric disturbances in the parameters of the ionospheric F 2 and sporadic E layers at the chain of the Japanese stations for vertical sounding of the ionosphere before strong crustal earthquakes with M>6.5 during the period from 1968 to 1992 have been considered. The dependence of the disturbance time of appearance in the ionospheric parameters on the earthquake magnitude and epicentral distance, obtained for each specific earthquake using the selected series of ionospheric stations, made it possible to consider these disturbances among medium-term precursors of earthquakes. The velocity of the disturbance front apparent motion has been determined based on the model of horizontal radially-isotropic disturbance propagation from the projection of the impending earthquake epicenter to the ionospheric altitudes. The conclusion has been made that the distinguished seismoionospheric disturbances follow the boundary of the earthquake preparation region, expanding on the Earth’s surface. 相似文献
10.
《Journal of Atmospheric and Solar》1999,61(8):619-628
This paper presents results of an experimental verification of our earlier suggested spectral-polarization method of measuring the interference pattern velocity by analyzing three mutually orthogonal projections of the radio signal field vector using a single receiving antenna. The measurements were made on an HF radio path about 100 km in length, with a simultaneous monitoring of the ionospheric situation using an oblique-incidence sounding chirp–ionosonde. In an effort to eliminate multipath effects, in the analysis we used nighttime intervals, for which a stable one-mode reflected radio signal was observed. It is shown that the proposed method gives the mean values of the azimuth and zenith angle which differ by no more than 2 to 5° from calculated values. Mean values of the velocity of travelling ionospheric disturbances (of order 50 m/s) and propagation directions (north-westward changing to northward by the morning hours) obtained for these time intervals are consistent with existing published data. 相似文献
11.
作为特例研究,本文对1988年和1990年两次强台风影响期间的电离层多普勒记录及相应的台风资料进行了细致的相关分析,目的是利用多普勒记录的连续性优点来了解电离层对登陆（或近海）强台风通过声重波响应的演化全过程.分析表明,在这两次台风影响期间,电离层形态中除有明显的波状扰动（中尺度声重波）出现外,还有一些值得注意的新现象：波动的时间演化表现出明显的幅度逐渐增加以及频率由高频向低频转变,在振幅很大的情况下日落后同时出现扩展F（Spread F）现象,显示了声重波在激发电离层不规则结构方面的种子作用.这一演化过程与电离层中TIDs的线性传播理论一致,文中开展了对这一现象的非线性数值模拟,模拟结果基本上也与上述观测现象相吻合. 相似文献
12.
B. G. Gavrilov Yu. I. Zetzer V. I. Kurkin I. E. Markovich Yu. V. Poklad M. Parrot I. A. Ryakhovskii V. V. Yakim 《Izvestiya Physics of the Solid Earth》2012,48(4):354-362
Variations in the geomagnetic and electric fields and variations of the total electron content (TEC) of the ionosphere recorded
in the Baikal Rift Zone (BRZ) during the expeditions in 2009 and 2010 are analyzed. Synchronous bursts in the geomagnetic
field on the ground and in the ionosphere, which are caused by propagation of electromagnetic disturbances (spherics) generated
by the remote lightning discharges, are revealed. The analysis of the occurrence frequency of the electromagnetic disturbances
at an altitude of ∼700 km shows that there is a preferred region of predominant propagation of these disturbances from the
Earth-ionosphere waveguide to the upper ionosphere. When the ionospheric penetration point moves through this preferred region,
the frequency spectrum of TEC variations changes, and the northern boundary of the region of spectral alteration is located
at ∼54°N. The bursts in TEC that map on the zones of the main faults in the Tunka valley are identified. The results probably
suggest a relation between the electromagnetic phenomena in the ionosphere and the structures in the lithosphere. 相似文献
13.
L. F. Chernogor 《Geomagnetism and Aeronomy》2014,54(5):613-624
An analysis was conducted of time variations in geomagnetic field components on the day of the Chelyabinsk meteorite event (February 15, 2013) and on control days (February 12 and 16, 2013). The analysis uses the data collected by magnetic observatories in Novosibirsk, Almaty, Kyiv, and Lviv. The distance R from the explosion site to the observatories varies in the range 1200–2700 km. The flyby and explosion of the Chelyabinsk cosmic body is found to have been accompanied by variations mainly in the horizontal component of the geomagnetic field. The variations are quasi-periodic with a period of 30–40 min, an amplitude of 0.5–2 nT for R ≈ 2700?1200 km, respectively, and a duration of 2–3 h. The horizontal velocity of the geomagnetic field disturbances is close to 260–370 m/s. A theoretical model of wave disturbances is proposed. According to the model, wave disturbances in the geomagnetic field are caused (a) by the motion of the gravity wave generated in the atmosphere by the falling space body and (b) by traveling ionospheric disturbances, which modulate the ionospheric current at dynamo altitudes. The calculated amplitudes of the wave disturbances are 0.6–1.8 nT for R ≈ 2700?1200 km, respectively. The estimates are in good agreement with the observational data. Disturbances in the geomagnetic field level (geomagnetic pulsations) in the period range 1–1000 s are negligible (less than 1 nT). 相似文献
14.
真实的ＴＩＤ一类大尺度电离层扰动是非平稳和色散的，而且是统计非单一的．本文首先给出了描述这种真实扰动场的数学模型，进而导出了联系台阵探测可测量与扰动场传播参量的观测方程，在此基础上提出了求解观测方程的时频分析方法．这一台阵探测数据分析的新方法，既能分离出非单一电离层扰动场中各种准单一扰动成分，又能获得准单一扰动成分传播参量随时间的演变和随频率的色散．分析实例表明，本文方法分辨率好，精度高，结果可靠，是适用于ＴＩＤ一类大尺度电离层扰动台阵探测数据分析的有效方法． 相似文献
15.
Using three radio techniques for determining the spatial and terminal distribution of the electron concentration in the ionospheric
F region, a number of parameters of medium-scale travelling ionospheric disturbances (the effective thickness of the atmospheric
waveguide and height of its axis, spatial and time periods, propagation speeds, and maximum amplitudes of the disturbances)
are determined. 相似文献
16.
N. A. Barkhatov S. E. Revunov G. G. Vertogradov V. G. Vertogradov V. A. Valov V. P. Uryadov 《Geomagnetism and Aeronomy》2006,46(1):84-93
The algorithm for predicting one of the main parameters of the ionospheric HF radio channel—maximum observed frequency (MOF)—for the interval 0.5–3 h has been synthesized based on the technology of artificial neural networks (ANNs). The data of oblique-incidence LFM sounding obtained on the Inskip (England)-Rostov-on-Don path have been used for this purpose. The studies have been performed under different geophysical conditions. The relation of MOF to the variations in the key parameters of the solar wind and IMF, responsible for the succession of development of magnetospheric-ionospheric disturbances leading to a change in the HF radiocommunication conditions, has been established. The time scales of the ionospheric response have been determined. The practical value of the performed work consists in that the obtained results are used to increase the reliability of ionospheric HF radiocommunication. 相似文献
17.
O. A. Pokhotelov M. Parrot E. N. Fedorov V. A. Pilipenko V. V. Surkov V. A. Gladychev 《Annales Geophysicae》1995,13(11):1197-1210
A review is presented of the effects influencing the ionosphere which are caused by acoustic emission from different sources (chemical and nuclear explosions, bolides, meteorites, earthquakes, volcanic eruptions, hurricanes, launches of spacecrafts and flights of supersonic jets). A terse statement is given of the basic theoretical principles and simplified theoretical models underlying the physics of propagation of infrasonic pulses and gravity waves in the upper atmosphere. The observations of “quick” response by the ionosphere are pointed out. The problem of magnetic disturbances and magnetohydrodynamic (MHD) wave generation in the ionosphere is investigated. In particular, the supersonic propagation of ionospheric disturbances, and the conversion of the acoustic energy into the so-called gyrotropic waves in the ionospheric E-layer are considered. 相似文献
18.
Large-scale disturbances in the ionospheric plasma, caused by the spacecraft launches from the Baikonur site, have been analyzed based on the incoherent scatter radar measurements. The altitude-time dependences of the main plasma parameters (electron density and electron and ion temperatures at altitudes of ～100–600 km) have been analyzed. It has been indicated that spacecraft launches and flights are accompanied by the generation of wave-like disturbances in all considered parameters. It has been obtained that the relative amplitudes of these wave-like disturbances were usually 0.03–0.10, and the variation period was 20–60 min. The variations were shifted in phase relative to each other. The propagation velocities of wave-like disturbances were ～0.5–0.6 and 1.5–2 km/s. The up-to-date methods of spectral analysis, including the wavelet analysis, were used to estimate the parameters of the wave-like disturbances. 相似文献
19.
E.N. Sergeev V.L. Frolov G.P. Komrakov B. Thidé T. Carozzi 《Journal of Atmospheric and Solar》1997,59(18):2383-2400
Experimental results concerning the growth and decay times of different spectral components of stimulated electromagnetic emission (SEE) are presented. A new method of measurement, employing a special pulsed pump scheme for the ionospheric plasma modification, has been elaborated and applied for studying HF-induced processes with high time resolution. The measurements performed show that the development and relaxation of different SEE features have an intricate pattern which depends on the emission frequency shift from the pump frequency, on the proximity of the pump frequency to the gyroharmonic frequencies, on the intensity of artificial ionospheric turbulence, and on the ionospheric conditions. The scope of this method for studies of HF plasma turbulence is discussed. 相似文献
20.
海平面的海啸波会产生大气重力波进而引发电离层扰动.本文利用日本GPS总电子含量数据来探测2011年3月11日Tohoku海啸引发的电离层扰动.观测结果表明,在日本上空的电离层中存在两种重力波信号,分别由海平面的海啸波以及地震破裂过程产生.地震产生的电离层重力波分布在震中周围（包括海洋上空以及远离海洋的区域）,而海啸引发的电离层重力波主要分布在海洋上空.地震产生的电离层重力波具有不同的水平速度,包括约210 m·s-1以及170 m·s-1,其频率为1.5 mHz;而海啸引发的电离层重力波水平速度快于前者,约为280 m·s-1,其频率为1.0 mHz.此外,海啸引发电离层重力波与海平面上的海啸波有相似的水平速度、方向、运行时间、波形以及频率等传播特征.本文的研究将电离层中的海啸信号与地震信号区分开来,进一步确认电离层对海啸波的敏感性. 相似文献