共查询到20条相似文献，搜索用时 31 毫秒
1.
The paper briefly reviews the preliminary results of observations of Alfvén ionospheric resonances performed in the northern Carpathian Mountains (south-eastern Poland) by the Cracow Schumann Resonances Group. The results confirm the simple models proposed recently by Lysak and Sentman. 相似文献
2.
Disturbances of the daily variations in the total electron content (TEC) of the ionosphere during and after geomagnetic storms, obtained from the observations of the GPS satellite signals, are considered. The specific features of these disturbances consist in the intensification of the variations with periods of 4–6 h, the amplitude of which increase at midlatitudes, and in a weak dependence of local maximums on latitude and their considerable longitudinal variability. The possibility of explaining observed disturbances of the considered daily variations by the generation of standing planetary Poincaré waves is discussed. The estimated periods of Poincaré waves, latitudinal structure of these waves, and their ionospheric effects make it possible to qualitatively explain the observed specific variations in TEC. 相似文献
3.
Laryunin O. A. Kurkin V. I. Berngardt O. I. Salimov B. G. Podlesnyi A. V. 《Geomagnetism and Aeronomy》2019,59(1):101-104
Geomagnetism and Aeronomy - Vertical ionograms often contain traces of reflections that cannot be attributed to any type of the sporadic Es layer and are classified as anomalous reflections.... 相似文献
4.
M. V. Klimenko V. V. Klimenko K. G. Ratovsky L. P. Goncharenko 《Geomagnetism and Aeronomy》2011,51(3):364-376
This study presents the ionospheric effects caused by the series of geomagnetic storms of September 9–14, 2005. The behavior
of different ionospheric parameters over the Yakutsk, Irkutsk, Millstone Hill and Arecibo stations during the considered period
have been numerically calculated, using a global self-consistent model of the thermosphere, ionosphere, and protonosphere
(GSM TIP) developed at WD IZMI-RAN. The model calculations of disturbances of the ionospheric parameters during storms qualitatively
agree with the experimental data at these midlatitude stations. We suggest that the causes of the quantitative differences
between the model calculations and the observational data were the use of the 3-hour Kp index of geomagnetic activity and the dipole approximation of geomagnetic field in GSM TIP, with additional contributions
from the effects of solar flares which are not considered in GSM TIP. 相似文献
5.
Geomagnetism and Aeronomy - The climatological features and behavior of the parameters B0_Neh_I, B1_Neh_I found from N(h) profiles calculated by the curves from the virtual heights during... 相似文献
6.
N. M. Polekh N. A. Zolotukhina E. B. Romanova S. N. Ponomarchuk V. I. Kurkin A. V. Podlesnyi 《Geomagnetism and Aeronomy》2016,56(5):557-571
Using vertical and oblique radio-sounding data, we analyze the ionospheric and thermospheric disturbances during the magnetic storm that occurred in northeastern Russia on March 17–19, 2015. We consider the heliospheric sources that induced the magnetic storm. During the main and early recovery phases, the midlatitude stations are characterized by extremely low values of electron density at the F2 layer maximum. Using oblique sounding data, we recorded signals that propagated outside the great circle arc. In evening and night hours, no radio signals were found to pass along the Norilsk–Irkutsk and Magadan–Irkutsk paths. The observed ionospheric effects are shown to be caused by a sharp shift of the boundaries of the main ionospheric trough to the invariant latitude 46° N during the main phase of the magnetic storm. The negative ionospheric disturbance during the recovery phase of the storm, which was associated with significant variations in the composition of the neutral atmosphere, led to a change in the mode composition of received radio signals and a decline in observed maximal frequencies in daytime hours of March 18, 2015 by more than 2 times. 相似文献
7.
Geomagnetism and Aeronomy - The results of the study of the dynamics of ionospheric Alfvén resonances (IARs) in a range of 0–10 Hz based on data from magnetic field observations at the... 相似文献
8.
E. I. Grigorenko V. N. Lysenko S. A. Pazyura V. I. Taran L. F. Chernogor 《Geomagnetism and Aeronomy》2007,47(6):720-738
Results of the study of the behavior of the F 2 region and topside ionosphere during the magnetic storm on November 7–10, 2004, which was a superposition of two sequent Severe magnetic disturbances (Kp = 9–) are presented. The observations were conducted by the incoherent scatter radar at Kharkov. Considerable effects of a negative ionospheric disturbance are registered, including a decrease in the electron density in the F 2-layer maximum by a factor of 6–7 and of the total electron content up to a height of 1000 km by a factor of 2, a lifting up of the ionospheric F 2 layer by 300 km at night and by 150–180 km in the daytime, unusual nighttime heating of the plasma with an increase of the ion and electron temperatures up to 2000 and 3000 K, respectively, and a decrease in the relative density of hydrogen ions N(H+)/N e by a factor of up to 3.5 because of the emptying of the magnetic flux tube passing over Kharkov. The effects usually observed in the high-latitude ionosphere, including the coherent echoes, are detected during the main phase of the storm. The results obtained manifest a shift of the large-scale structures of the high-latitude ionosphere (the auroral oval, main ionospheric trough, hot zone, etc.) down to latitudes close to the latitude of the Kharkov radar. 相似文献
9.
Prikner K. Mursula K. Kangas J. Feygin F. Z. Kerttula R. 《Studia Geophysica et Geodaetica》2002,46(3):507-526
The ionospheric Alfvén resonator (IAR) was numerically simulated under non-stationary ionospheric and magnetospheric conditions of the IPDP event of December 4, 1986. The full numerical wave method was applied using height profiles of the ionospheric plasma parameters obtained from the Scandinavian EISCAT radar measurements close to the Ivalo latitude. An attempt to model the inverse problem of numerical simulation—prolongation of the electron density profiles at altitudes above the ionospheric F layer—was made on the basis of the IAR simulation in correlation with the IPDP frequency increase. The change of the IAR wave characteristics during the substorm was illustrated by height profiles of the total wave amplitude and various polarization characteristics, taking into consideration the ordinary L-mode and the extraordinary R-mode waves for parallel and non-parallel incidence with respect to the magnetic field line. 相似文献
10.
F. N. Okeke 《Surveys in Geophysics》2000,21(5-6):487-498
A review of ionospheric currents,the external part of geomagnetic solar quiet (Sq)variation and the internal part of the induced currentwithin the Earth, has been carried out.The theoretical background has been reviewed,and the method of analysis, specificallythe spherical harmonic analysis (SHA),is presented. Various works are reviewed andfully discussed. It has been noted that anew model of the Sq current system could beused to obtain a mantle electrical conductivityprofile for hemispheres. It is suggested thatfurther research work be carriedout in other hemispheres using similarmodels for more robust interpretations. 相似文献
11.
A destructive shock with magnitude of 6.3 occurred on 2 June 2007 at 21h34min56s UT in Pu’er region (23.0°N, 101.1°E), Yunnan Province, China. The data from DEMETER satellite during the period from 23 May to 2 June, i.e., ten days before the earthquake and one day just on the day of earthquake occurrence, were analyzed. Among the 284 orbits of DEMETER during the period, 29 orbits with the trace passing through the region within 1 888 km from the epicenter were selected to be studied. Seven anomalous events were found on the dataset of the seven orbits among the 29 ones. There existed synchronous perturbations on the variations of the spectrogram of the electric field and the variations of the density and temperature of the ions and electron, in contrast with the variations of its surround- ing area. And five events appeared in the space within 1 888 km from the epicenter while the other two were out of the studied area. Electrostatic turbulences were also recorded with the synchronous perturbations with that in the electron density and ions density in plasma in the region near the epicenter in the five events, which seems to sug- gest that there be some physical relation between these events and the preparation processes of Pu’er earthquake. 相似文献
12.
The response of the critical frequency of the ionosphere F2–layer, described by its main Fourier components (daily constant, diurnal and semidiurnal waves) and the lower thermosphere dynamics to the geomagnetic storms in July 1991 and February 1992 is studied. The daily constant displays a negative response, however, the magnitude of reaction depends on the season and latitude. The amplitudes of diurnal and semidiurnal waves increase during a geomagnetic storm, as this enhancement is very strong at high latitudes in winter. The prevailing neutral wind, especially the zonal wind, shows an inclination to decrease during the geomagnetic storm (the effect is more distinct in summer). The amplitudes of diurnal and semidiurnal tides also demonstrate a tendency toward reduction during high geomagnetic activity. 相似文献
13.
14.
A Polish-made vertical ionosonde (VI) has been operated at the Kandilli Observatory in Istanbul, for almost one year (May 1993 - April 1994) as part of the COST 238, PRIME Project, The critical frequencies were obtained for every half-hour interval. The data obtained during this campaign, on the descending branch of solar cycle 22, and the data measured earlier in Istanbul for cycle 20 were analysed and the characteristic behaviour of the F2 region ionosphere over Istanbul has been determined. This is a unique data set for this area. Several markers of the solar cycle activities in terms of the daily relative sunspot numbers, F10.7 cm solar radio flux and solar flare index, and the magnetic daily index of Ap were then used to seek the possible influence of the solar and ionospheric activities on the critical frequencies observed in Istanbul. It was found that the solar flare index, as a solar activity index, was more reliable in determining quiet ionospheric days. It is shown that the minimum and maximum time values of the solar activity are more convenient for ionospheric prediction and modelling. 相似文献
15.
Geomagnetism and Aeronomy - The behaviour of the ionospheric F2-layer during geomagnetic storm is studied using the critical frequency parameter foF2. The magnetic storms of 2nd October 2013 and... 相似文献
16.
陈培善 《地震学报(英文版)》2002,(6)
For showing the epicenter distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in 6-th issue each year. Figure 1 and 2 represent the epicentral distribution in and near China and all over the world in 2001, respectively. Map of epicentre distribution for 2001@陈培善$InstituteofGeophysics,ChinaSeismologicalBureau!Beijing100081,China… 相似文献
17.
陈培善 《地震学报(英文版)》2001,(6)
For showing the epicentral distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in the 6-th issue each year. Figures 1 and 2 represent the epicentral distribution in and near China and all over the world in 2000, respectively. ~~Map of epicentre distribution for 2000@陈培善… 相似文献
18.
Ionospheric precursor of a destructive earthquake that occurred on April 6, 2009 at L’Aquila (Italy)
On the basis of the 15-min data from a series of ground-based vertical ionospheric sounding stations, a study of variations
of the foF2 critical frequency before the strong earthquake (M = 6.3) that occurred on April 6, 2009 at L’Aquila (Italy) was carried out. The earthquake epicenter was located 85 km north-eastward
from Rome. Approximately 20 h prior to the earthquake, a well-pronounced statistically significant effect of foF2 increase relative to the average background for magnetically quiet days was observed for almost 1.5 h at the Rome ionospheric
station. In this case, at control stations distanced from the earthquake epicenter, no statistically significant deviations
of foF2 from the background values were detected during the same observations period. This fact provides grounds for consideration
of the foF2 increase observed at Rome station as a possible ionospheric precursor of this earthquake. 相似文献
19.