Ionospheric Precursors of Geomagnetic Storms. 1. A Review of the Problem

Geomagnetism and Aeronomy - The problem of the occurrence of disturbances of the ionospheric F2-layer parameters prior to the beginning of a geomagnetic storm is discussed. It is shown that...     

Ionospheric Precursors of Magnetic Storms. 2. Analysis of Slough Station Data

Geomagnetism and Aeronomy - The behavior of the critical frequency of the F2 layer, foF 2, during the 3 days preceding a magnetic storm is analyzed. A total of 254 storms in 1976–2010...     

Ionospheric Disturbances during Meteorological Storms

Geomagnetism and Aeronomy - Ionospheric disturbances during meteorological storms in the Kaliningrad region with a wind amplification of 8 points or higher on the Beaufort scale for the period...     

Comparison of Ionospheric Parameters during Similar Geomagnetic Storms

The degree of closeness of ionospheric parameters during one magnetic storm and of the same parameters during another, similar, storm is estimated. Overall, four storms—two pairs of storms close in structure and appearance according to recording of the magnetic field Х-component—were analyzed. The examination was based on data from Sodankyla observatory (Finland). The f-graphs of the ionospheric vertical sounding, magnetometer data, and riometer data on absorption were used. The main results are as follows. The values of the critical frequencies foF2, foF1, and foE for different but similar magnetic storms differ insignificantly. In the daytime, the difference is on average 6% (from 0 to 11.1%) for all ionospheric layers. In the nighttime conditions, the difference for foF2 is 4%. The nighttime values of foEs differ on average by 20%. These estimates potentially make it possible to forecast ionospheric parameters for a particular storm.     

Global-Scale Coupling Characteristics between Geomagnetic Storms and Ionospheric Disturbances

Geomagnetism and Aeronomy - To explore the global-scale coupling characteristics between ionospheric disturbances and geomagnetic storms, and research the near-Earth space environment, the time...     

Method for Cognitive Identification of Ionospheric Precursors of Earthquakes

Geomagnetism and Aeronomy - A significant proportion of publications related to the ionospheric disturbances that arise during earthquake preparation over the regions of their preparation refer to...     

Effect of Magnetic Storms on Low-Frequency Seismic Noise

Izvestiya, Physics of the Solid Earth - Abstract—The response of seismic noise in the minute range of periods to the strong magnetic storms is studied. The noise is analyzed from the records...     

Magnetic and Ionospheric Effects of a Meteoroid Plume

This paper is concerned with the study of the possibility of products of a meteoroid explosion in the atmosphere (meteoroid plume) to reach ionospheric altitudes. It has been shown that, in the case of meter-sized or larger space bodies entering the atmosphere, the plume is able to reach the lower ionosphere. The plume can be one of the sources of the formation of nacreous and noctilucent clouds. The aerosols ejected by the plume to lower ionospheric altitudes can lead to the formation of dust plasma, significantly changing the electrodynamic properties of the medium. The motion of the plume with a velocity of ~1 km/s is accompanied by the generation of a ballistic shock with a radius of 1–10 km. The relative excess pressure in the shock front can cause relative disturbances in the electron content at the altitudes of D, E, and F1 layers by ~10–100%. The geomagnetic effect of the plume and ballistic shock can reach ~1–10 nT.     

基于陆态网络GNSS数据的2013年和2015年磁暴期间中国地区电离层特性研究

2013年3月和2015年3月爆发了2次相似的地磁暴,引起了全球不同地区电离层的变化。本文利用中国大陆构造环境监测网络260余个基准站在中国地区的GNSS电离层TEC观测数据,结合电离层测高仪和电离层甚高频相干散射雷达观测,对2次磁暴期间中国地区的电离层变化特性进行了对比分析。结果显示,2013年3月磁暴期间,中国不同地区电离层变化较弱或不明显,而2015年3月磁暴期间中国地区电离层变化整体表现为大范围的强负相暴,中国地区不同程度的电离层响应主要受到不同的磁暴强度和磁暴期间不同的能量输入影响。2次磁暴期间电离层F层不均匀体的发生受到不同程度的影响,可能由不同种类的暴时电场导致。陆态网络数据空间覆盖范围广、时间分辨率高,在研究中国地区磁暴期间的电离层变化特性方面具有优势。     

The Effect of Strong Magnetic Storms on the Occurrence of Large Earthquakes

Izvestiya, Physics of the Solid Earth - Abstract—The times of occurrence of the earthquakes with magnitudes M ≥ 6.5 all over the world are compared with the commencement times of the...     

Effect of Weak Magnetic Storms on the Propagation of HF Radio Waves

Geomagnetism and Aeronomy - Vertical and oblique sounding data for northeastern Russia have been used to analyze the conditions for the propagation of radio waves during weak geomagnetic storms...     

Possible Generation of Quasi-Periodic Magnetic Precursors of Earthquakes

Geomagnetism and Aeronomy - A mechanism for the generation of quasi-periodic magnetic precursors of earthquakes is proposed on the basis of air heating above an impending earthquake, the rise of...     

Investigation of Ionospheric Response to Geomagnetic Storms over a Low Latitude Station,Ile-Ife,Nigeria

Due to several complexities associated with the equatorial ionosphere, and the significant role which the total electron content (TEC) variability plays in GPS signal transmission, there is the need to monitor irregularities in TEC during storm events. The GPS SCINDA receiver data at Ile-Ife, Nigeria, was analysed with a view to characterizing the ionospheric response to geomagnetic storms on 9 March and 1 October 2012. Presently, positive storm effects, peaks in TEC which were associated with prompt penetration of electric fields and changes in neutral gas composition were observed for the storms. The maximum percentage deviation in TEC of about 120 and 45% were observed for 9 March and 1 October 2012, respectively. An obvious negative percentage TEC deviation subsequent to sudden storm commencement (SSC) was observed and besides a geomagnetic storm does not necessarily suggest a high scintillation intensity (S₄) index. The present results show that magnetic storm events at low latitude regions may have an adverse effect on navigation and communication systems.     

Investigation of Ionospheric Variations During Magnetic Storm Over Turkey

Geomagnetism and Aeronomy - Variations in solar, geomagnetic, and seismic activity cause disturbance in the ionosphere that can be monitored effectively using GPS observations. Total electron...     

Differences in the Dynamics of the Asymmetrical Part of the Magnetic Disturbance during the Periods of Magnetic Storms Induced by Different Interplanetary Sources

Geomagnetism and Aeronomy - The differences in the dynamics of the asymmetrical part of the geomagnetic disturbance at middle and low latitudes during magnetic storms initiated by different...     

Possible Short-Term Precursors of Strong Crustal Earthquakes in Japan based on Data from the Ground Stations of Vertical Ionospheric Sounding

We have studied changes in the ionosphere prior to strong crustal earthquakes with magnitudes of М ≥ 6.5 based on the data from the ground-based stations of vertical ionospheric sounding Kokobunji, Akita, and Wakkanai for the period 1968–2004. The data are analyzed based on hourly measurements of the virtual height and frequency parameters of the sporadic E layer and critical frequency of the regular F2 layer over the course of three days prior to the earthquakes. In the studied intervals of time before all earthquakes, anomalous changes were discovered both in the frequency parameters of the Es and F2 ionospheric layers and in the virtual height of the sporadic E layer; the changes were observed on the same day at stations spaced apart by several hundred kilometers. A high degree of correlation is found between the lead-time of these ionospheric anomalies preceding the seismic impact and the magnitude of the subsequent earthquakes. It is concluded that such ionospheric disturbances can be short-term ionospheric precursors of earthquakes.     

Large-Scale Disturbances Features Induced in the Ionosphere by Powerful Decameter Radiation during Moderate Magnetic Storms

Geomagnetism and Aeronomy - The paper presents the results of experimental studies of aperiodic and quasi-periodic disturbances in the ionosphere that were observed under the influence of powerful...     

Determination of the Enhancement in Electron Temperature in the Subauroral Ionosphere during Magnetic Storms on a Global Scale

Geomagnetism and Aeronomy - An attempt was made to determine on a global scale the zone of enhanced electron temperature (Te) in the subauroral ionosphere during magnetic storms via the combination...     

地磁垂直分量Z日变幅逐日比及其与磁暴和地震的关系

地磁垂直分量Z日变幅逐日比是基于变化磁场在地球电导率的作用下会产生一个与变化磁场相反的感应磁场, 该感应磁场不仅包含了外空磁场的信息, 还包含了地下电导率的信息。 因此, 相对于地磁场其他成分来说Z分量更多地反应了地下活动的变化, 逐日比是利用前后两日地磁Z分量日变幅相比来提取该异常现象, 但磁暴可能会对逐日比异常判定产生影响。 我们取1984年至今江苏区域范围达到逐日比异常判定指标的29个事件结合磁暴以及该异常事件之后和地震的对应关系进行统计分析。 研究发现, 无磁暴时逐日比异常和预测范围内地震对应关系达到0.77, 有磁暴时逐日比异常和地震对应关系为0.25。 综合分析认为逐日比异常事件发生后, 若该日无磁暴或者Dst指数小于异常第二日, 那么该异常为地震前兆的可能性大概为0.8, 反之则该异常有可能是磁暴的影响而不是来自于地下活动的影响, 需结合其他前兆分析方法进行综合分析, 该研究增强了逐日比异常判定地震地磁前兆信息的可靠性。     

Dynamics of Interplanetary Parameters and Geomagnetic Indices during Magnetic Storms Induced by Different Types of Solar Wind

Geomagnetism and Aeronomy - Based on the OMNI2 archival data for 1995–2017, the dynamics of geomagnetic activity indices (Dst, ap, AE, and PC) and interplanetary parameters over the periods...