scholarly journals Analysis of geomagnetic disturbances dynamics during increased solar activity and magnetic storms (according to the measurements of INTERMAGNET station network)

2019 ◽  
Vol 127 ◽  
pp. 02003
Author(s):  
Oksana Mandrikova ◽  
Anastasia Rodomanskay ◽  
Alexander Zaitsev
Keyword(s):  
Geomagnetic Activity ◽  
Geomagnetic Field ◽  
Auroral Zone ◽  
Magnetic Storms ◽  
Magnetic Data ◽  
Field Variation ◽  
Geomagnetic Disturbances ◽  
Station Network ◽  
Ground Station ◽  
Automated Method

We present and describe an automated method for analysis of magnetic data and for detection of geomagnetic disturbances based on wavelet transformation. The parameters of the computational algorithms allow us to estimate the characteristics of non-uniformly scaled peculiar properties in the variations of geomagnetic field that arise during increasing geomagnetic activity. The analysis of geomagnetic data before and during magnetic storms was carried out on the basis of the method according to ground station network. Periods of increasing geomagnetic activity, which precede and accompany magnetic storms, are highlighted. The dynamic of geomagnetic field variation in the auroral zone is considered in detail.

scholarly journals Dynamics and spatio-temporal distribution of geomagnetic disturbances during periods of increased solar activity and magnetic storms

2020 ◽  
Vol 196 ◽  
pp. 02009
Author(s):  
Oksana Mandrikova ◽  
Anastasia Rodomanskay
Keyword(s):  
Cross Correlation ◽  
Temporal Distribution ◽  
Temporal Analysis ◽  
Auroral Zone ◽  
Magnetic Storms ◽  
Magnetic Data ◽  
Geomagnetic Disturbances ◽  
Short Period ◽  
Adaptive Thresholds ◽  
Spatio Temporal

A detailed spatio-temporal analysis of magnetic data was performed during the periods of magnetic storms on October 02, 2013 and September 27, 2019 based on measurements of the station network. In this work, we used a method developed by us for the analysis of magnetic data, based on the use of wavelet transform and adaptive thresholds. The method allows us to identify short-period field disturbances and estimate their intensity from the data of the H-component of the geomagnetic field. The features of the occurrence and propagation of geomagnetic disturbances in the auroral zone and at meridionally located stations have been studied. Dynamic spectra of disturbances of different intensity and duration are obtained. The paper confirms the possibility of occurrence of short-period weak geomagnetic disturbances at stations from high latitudes to the equator, preceding magnetic storms and correlating with fluctuations of the southern Bz-component of the interplanetary magnetic field and increases in the auroral indices of geomagnetic activity. Cross-correlation dependences of the intensity of geomagnetic disturbances on the parameters of the interplanetary medium during magnetic storms were obtained from the data of the network of magnetic stations. A statistically significant influence of the magnitude of the scope of the Bz-component of the IMF and the speed of the solar wind on the development of magnetic storms during the initial and main phases of magnetic storms was revealed.

scholarly journals Analysis of magnetic data of ground station network during strong magnetic storms

2017 ◽  
Vol 20 ◽  
pp. 02008 ◽  
Author(s):  
Oksana Mandrikova ◽  
Igor Solovev ◽  
Sergey Khomutov ◽  
Dmitry Baishev ◽  
Phani Chandrasekhar
Keyword(s):  
Magnetic Storms ◽  
Magnetic Data ◽  
Station Network ◽  
Ground Station

scholarly journals Magnetic local time dependence of geomagnetic disturbances contributing to the AU and AL indices

2011 ◽  
Vol 29 (4) ◽  
pp. 673-678 ◽  
Author(s):  
S. Tomita ◽  
M. Nosé ◽  
T. Iyemori ◽  
H. Toh ◽  
M. Takeda ◽  
...  
Keyword(s):  
Local Time ◽  
Geomagnetic Field ◽  
Field Data ◽  
Geomagnetic Latitude ◽  
Magnetic Activity ◽  
Auroral Zone ◽  
Magnetic Local Time ◽  
Geomagnetic Disturbances ◽  
Current Systems ◽  
Local Time Dependence

Abstract. The Auroral Electrojet (AE) indices, which are composed of four indices (AU, AL, AE, and AO), are calculated from the geomagnetic field data obtained at 12 geomagnetic observatories that are located in geomagnetic latitude (GMLAT) of 61.7°–70°. The indices have been widely used to study magnetic activity in the auroral zone. In the present study, we examine magnetic local time (MLT) dependence of geomagnetic field variations contributing to the AU and AL indices. We use 1-min geomagnetic field data obtained in 2003. It is found that both AU and AL indices have two ranges of MLT (AU: 15:00–22:00 MLT, ~06:00 MLT; and AL: ~02:00 MLT, 09:00–12:00 MLT) contributing to the index during quiet periods and one MLT range (AU: 15:00–20:00 MLT, and AL: 00:00–06:00 MLT) during disturbed periods. These results are interpreted in terms of various ionospheric current systems, such as, Sqp, Sq, and DP2.

IV.—The Electric Field in Terrestrial Magnetic Storms

1932 ◽  
Vol 57 (1) ◽  
pp. 143-177 ◽  
Author(s):  
A. H. R. Goldie
Keyword(s):  
Electric Fields ◽  
Auroral Zone ◽  
Magnetic Storms ◽  
Point Of View ◽  
Magnetic Data ◽  
Magnetic Disturbance ◽  
The Earth ◽  
The Mean ◽  
Annual Changes ◽  
Extreme North

The paper which follows is based in the main on the magnetic records of the observatories at Lerwick (Shetland) and Eskdalemuir (Dumfriesshire), though reference is made to the data of Abinger (Surrey), Sitka (Alaska), Sodankylä (Finland), Colaba (Bombay), and Mauritius, and to records made at different times at Arctic and Antarctic stations. The situation of the Lerwick observatory, just within the auroral zone, might be expected to give to its records an outstanding value in any investigation connected with magnetic storms; the expectation has not been disappointed. The distance between Abinger and Eskdalemuir is about 470 km., and between Eskdalemuir and Lerwick about 550 km.—both quantities small compared with the dimensions of the earth—yet the mean ranges of disturbance at these three places appear to run roughly in the ratio 1:2: 4½. This at once suggests that in the extreme north of the British Isles we approach a zone of exceptional interest from the point of view of magnetic disturbance; and further,-that with suitable magnetic data some attempt might be made to compute the disturbing electric fields, at least in their main features, and possibly to arrive at some idea of any seasonal and annual changes to which these fields may be subject.

Models of the geomagnetic field and characteristics of magnetic storms

2006 ◽  
Vol 12 (1) ◽  
pp. 64-69
Author(s):  
O.I. Maksimenko ◽  
◽  
L.N. Yaremenko ◽  
O.Ya. Shenderovskaya ◽  
G.V. Melnyk ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Magnetic Storms

Stochastic investigation of daily air temperature extremes from a global ground station network

2021 ◽  
Author(s):  
Konstantinos-Georgios Glynis ◽  
Theano Iliopoulou ◽  
Panayiotis Dimitriadis ◽  
Demetris Koutsoyiannis
Keyword(s):  
Air Temperature ◽  
Temperature Extremes ◽  
Station Network ◽  
Ground Station

THE STUDY OF LONGITUDINAL AND LATITUDINAL VARIATION OF EQUATORIAL ELECTROJET SIGNATURE AT STATIONS WITHIN THE 96°MM AND 210°MM AFRICAN AND ASIAN SECTORS RESPECTIVELY UNDER QUIET CONDITIONS.

2021 ◽  
Vol 5 (2) ◽  
pp. 511-532
Author(s):  
Aniefiok Akpaneno ◽  
Matthew Joshua ◽  
K. R. Ekundayo
Keyword(s):  
Seasonal Variation ◽  
Geomagnetic Field ◽  
Satellite Communication ◽  
Equatorial Electrojet ◽  
Latitudinal Variation ◽  
Magnetic Data ◽  
Horizontal Magnetic Field ◽  
Baseline Values ◽  
The Difference ◽  
Current Systems

Solar quiet current (S_q) and Equatorial Electrojet (EEJ) are two current systems which are produced by electric current in the ionosphere.  The enhancement of the horizontal magnetic field is the EEJ. This research is needed for monitoring equatorial geomagnetic current which causes atmospheric instabilities and affects high frequency and satellite communication. This study presents the longitudinal and latitudinal variation of equatorial electrojet signature at stations within the 96°mm and 210°mm African and Asian sectors respectively during quiet condition. Data from eleven observatories were used for this study. The objectives was  to determine the longitudinal and latitudinal geomagnetic field variations during solar quiet conditions, Investigate monthly variation and diurnal transient seasonal variation; Measure the strength of the EEJ at stations within the same longitudinal sectors and find out the factors responsible for the longitudinal and latitudinal variation of EEJ. Horizontal (H) component of geomagnetic field for the year 2008 from Magnetic Data Acquisition System (MAGDAS) network were used for the study. The International Quiet Days (IQDs) were used to identify quiet days. Daily baseline values for each of the geomagnetic element H  were obtained.  The monthly average of the diurnal variation was found. The seasonal variation of dH was found. Results showed that: The longitudinal and latitudinal variation in the dH differs in magnitude from one station to another within the same longitude due to the difference in the influence of the EEJ on them.

scholarly journals Brief communication "On the recent reaffirmation of ULF magnetic earthquakes precursors"

2011 ◽  
Vol 11 (8) ◽  
pp. 2193-2198 ◽  
Author(s):  
F. Masci
Keyword(s):  
Geomagnetic Activity ◽  
Geomagnetic Field ◽  
Earthquake Precursors

Abstract. Hayakawa et al. (2009) and Hayakawa (2011) have recently reviewed some "anomalous" ULF signatures in the geomagnetic field which previous publications have claimed to be earthquake precursors. The motivation of this review is "to offer a further support to the definite presence of those anomalies". Here, these ULF precursors are reviewed once again. This brief communication shows that the reviewed anomalies do not "increase the credibility on the presence of electromagnetic phenomena associated with an earthquake" since these anomalous signals are actually caused by normal geomagnetic activity. Furthermore, some of these ULF precursors have just been rebutted by previous publications.

scholarly journals Evaluation of the geometry of ionospheric current systems related to rapid geomagnetic variations

2004 ◽  
Vol 22 (1) ◽  
pp. 63-72 ◽  
Author(s):  
S. V. Apatenkov ◽  
V. A. Sergeev ◽  
R. Pirjola ◽  
A. Viljanen
Keyword(s):  
Dynamic Pressure ◽  
Auroral Oval ◽  
Auroral Zone ◽  
Middle Part ◽  
Magnetic Storms ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Variations ◽  
Ionospheric Current ◽  
Solar Wind Parameters ◽  
Current Systems

Abstract. To learn about the geometry and sources of the ionospheric current systems which generate strong geomagnetically induced currents, we categorize differential equivalent current systems (DEC) for events with strong dB/dt by decomposing them into the contributions of electrojet-type and vortex-type elementary systems. By solving the inverse problem we obtain amplitudes and locations of these elementary current systems. One-minute differences of the geomagnetic field values at the IMAGE magnetometer network in 1996–2000 are analysed to study the spatial distributions of large dB/dt events. The relative contributions of the two components are evaluated. In particular, we found that the majority of the strongest dB/dt events (100–1000nT/min) appear to be produced by the vortex-type current structures and most of them occur in the morning LT hours, probably caused by the Ps6 pulsation events associated with auroral omega structures. For strong dB/dt events the solar wind parameters are shifted toward strong (tens nT) southward IMF, enhanced velocity and dynamic pressure, in order for the main phase of the magnetic storms to occur. Although these events appear mostly during magnetic storms when the auroral oval greatly expands, the area of large dB/dt stays in the middle part of the auroral zone; therefore, it is connected to the processes taking part in the middle of the magnetosphere rather than in its innermost region populated by the ring current. Key words. Geomagnetism and paleomagnetism (rapid time variations) – Ionosphere (auroral ionosphere; ionospheric disturbances)

scholarly journals Natural hazards and technological risk in Russia: the relation assessment

2005 ◽  
Vol 5 (4) ◽  
pp. 459-464 ◽  
Author(s):  
E. Petrova
Keyword(s):  
Natural Hazards ◽  
Field Variation ◽  
Geomagnetic Disturbances ◽  
Regional Environment ◽  
Geophysical Field ◽  
Technological Risk ◽  
Technological Disasters ◽  
Toxic Emissions ◽  
Automatic Machinery ◽  
Solar Disturbances

Abstract. Almost every natural disaster is accompanied by some sort of technological one. A number of studies also show a correlation between technological disasters and various global processes such as solar disturbances, geophysical field variation etc. In this study we attempted to ascertain and codify the relationship between different types of technological disasters and natural hazards. Two types of natural hazards were found, based on their genesis, distribution in time, and impact pattern on the technosphere. Solar and geomagnetic disturbances generally affect technological risk through the failure of automatic machinery and the reduction of operator reliability. They increase the probability of transport accidents, fires, and catastrophic toxic emissions. These types of technological disasters are widely prevalent throughout Russia and in all federal regions. Geological, climatic, hydrological, and other natural hazardous processes increase technological risk through direct mechanical impacts. Their occurrence in space and time depends on the character of the natural process and the specific regional environment. The total number and proportion of technological disasters in federal regions results mainly from the concentration of industrial units and their type, as well as the local natural and social environment. Temporal changes in the number of technological disasters of different groups depend on the prevailing type of natural processes.

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