2005 Vol. 25, No. 5

Display Method:
Ray Structure of the Coronal Streamer Belt and Its Manifestation as Sharp Large Peaks of Solar Wind Plasma Density at the Earth's Orbit
M. V. Eselevich, V. G. Eselevich, Z. Q. Zang
2005, 25(5): 321-328. doi: 10.11728/cjss2005.05.321
Abstract:
The white-light corona calibrated data with processing level L1 from the LASCO-C2/SOHO instrument, and data from the Wind spacecraft with one-hour and one-minute time resolution on quasi-stationary slow (v between 300-450 km/s at the Earth's orbit) the Solar Wind (SW) parameters in the absence of sporadic SW streams are examined. Within distances from the Sun's center less than R in the range of 20-30 Rs,(Rs, the solar radius), slow wind is known as the streamer belt, and at larger distances it is called the Heliospheric Plasma Sheet (HPS). It is shown that the streamer belt comprises a sequence of pairs of rays. In general, ray brightnesses in each pair can differ, and the magnetic field is oppositely directed in them. The neutral line of the radial magnetic field of the Sun runs along the belt between the rays of each of the pairs.The area in which the streamer belt intersects the ecliptic plane and which lies at the central meridian, will be recorded at the earth's orbit with a time delay of 5-6 days, in the form of one or several peaks with Nmax > 10 cm-3. Furthermore, the simplest density profile of the portion of the HCS has the form of two peaks of a different or identical amplitude . The such a profile is observed in cases where the angle of intersection of the streamer belt with the ecliptic plane near the Sun is sufficiently large, i.e. close to 90°. The two-ray structure of the cross-section of the streamer-belt moves from the Sun to the Earth, it retains not only the angular size of the peaks but also the relative density variations, and the position of the neutral line(sector boundary) in between. At the Earth's orbit the ray structure of the streamer belt provides the source for sharp (i.e. with steep fronts of a duration of a few minutes or shorter) solar wind plasma density peaks (of a duration of several hours) with maximum values Nmax > 10 cm-3.
Structure of the Program of Short-term Prediction of Powerful Solar Flares
V. Maksimov, D. Prosovetsky
2005, 25(5): 329-332. doi: 10.11728/cjss2005.05.329
Abstract:
Input data of the system are two-dimensional images and one-dimensional distributions of total and polarized solar emission at 5.2 cm wavelength obtained with SSRT. Together with photoheliograms, magnetograms, Hα-filtergrams and characteristics of active regions received from other sources, they form the initial database. The first stage includes superimposing the images, identifying microwave sources with active regions, assigning NOAA numbers to the sources, and determining for each active region the heliolatitude, extent, and inclination angle of the group's axis to the equator. These data are used to calculate the boundaries of longitude zones for each active region. A next stage involves determining the brightness temperatures of microwave sources less than the polarization distribution, the degree of polarization, and microwave emission flux, as well as calculating the parameters of microwave sources. Each parameter is assigned its own value of the weight factor, and the sum of values is used to draw the conclusion about the flare occurrence probability in each active region and on the Sun in general.
Fractal Structure of the Heliospheric Plasma Sheet at the Earth's Orbit
M. V. Eselevich, V. G. Eselevich
2005, 25(5): 333-337. doi: 10.11728/cjss2005.05.333
Abstract:
An analysis of the data from the Wind and IMP-8 spacecraft revealed that a slow solar wind,flowing in the heliospheric plasma sheet, represents a set of magnetic tubes with plasma of increased density(N > 10cm-3 at the Earth's orbit). They have a fine structure at several spatial scales (fractality), from2°-3° (at the Earth's orbit, it is equivalent to 3.6-5.4 h, or(5.4-8.0) × 106 km) to the minimum about0.025°, i.e. the angular siz.e of the nested tubes is changed nearly by two orders of magnitude. The magnetic tubes at each observed spatial scale are diamagnetic, i.e. their surface sustains a flow of diamagnetic (or drift)current that decreases the magnetic field within the tube itself and increases it outside the tube. Furthermore,the value of β = 8π[N(Te + Tp)]/B2 within the tube exceeds the value of β outside the tube. In many cases total pressure P = N(Te + Tp) + B2/8π is almost constant within and outside the tubes at any one of the aforementioned scales.
Radio Heliographic Diagnostics of Solar Activity That Governs Space Weather
G. Y. Smolkov
2005, 25(5): 338-344. doi: 10.11728/cjss2005.05.338
Abstract(1784) PDF 666KB(1019)
Abstract:
In this paper, the possibility and some results of radioheliographic study of space weather solar factors are shortly described.
Shareable Instruments and Observatories for the Joint Research Center on Space Weather of the Siberian Branch of Russian Academy of Sciences and Chinese Academy of Sciences
G. Y. Smolkov
2005, 25(5): 345-350. doi: 10.11728/cjss2005.05.345
Abstract:
Presented are the ideas and proposals in regards to the pooling of by RAS, SB, ISTP, and CSSAR,CAS toward coordinated usage of existing ground-based and orbiting helio-geophysical observatories, single large installations as well as creating, forecasting services and new observing facilities, in the interests of achieving a profitable activity of the China-Russia Joint Research Center on Space Weather (JRCSW).
The Main Results and the Perspectives in the Researches at SSRT
G. Y. Smolkov, S. V. Lesovoy, V. G. Z, anov, A. T. Altyntsev, A.V. Gubin
2005, 25(5): 351-355. doi: 10.11728/cjss2005.05.351
Abstract:
In this report briefly presented the contemporary state of the experimental base of Radio Astrophysical Observatory (RAO) of the Institute of Solar-Terrestrial Physics (ISTP), the methodology of radioheliographic monitoring of the solar corona, the SSRT database, the RAO Web-pages, factors limiting the effective use of SSRT. Here are formulated the original results of the basic directions of the solar activity researches and the problems solutions on SSRT: (1) active regions at various development stages, morphology, modeling,signs of energy accumulation and flares buildup, forecast of powerful flares; (2) scenario, topology and the fine temporal picture of flares development, signs of primary energy release, radio emission mechanisms, scatter effects of radio emission in turbulent corona, energetic particles fluxes; (3) filaments; (4) CME with the localization of their initiation at the solar disk background, development scenario of filament activation + CME +flare; (5) coronal holes, and (6) bright coronal points.
The Physical Foundation of Forecasting Disturbances in the Geospace From Solar Disk Characteristics
V. G. Eselevich, M. V. Eselevich
2005, 25(5): 356-361. doi: 10.11728/cjss2005.05.356
Abstract:
The five main types of antisunward propagating energetic fluxes (particles and emission) may be thought of as well established to date, the effects of which lead to a particilar character of disturbance in the near-terrestrial environment (the Earth's magnetosphere, ionosphere and atmosphere). The strongest global restructuring of the magnetosphere and ionosphere is caused by fluxes of relatively dense n of 1-70 cm-3 at the Earth's orbit) Solar Wind (SW) quasi-neutral, low-energy (E < 10 keV) plasma which cause magnetospheric and ionospheric storms lasting 24 hours or longer. For that reason, main attention is given to their study at the initial stage of research. The physical essence of the method of predicting disturbances in the near-terrestrial space environment, the amplitude of which can be expressed in, for example, the Kp index units, involves:(1) identifying all the most geo-effective SW streams of type, (2) determing their sources on the solar disk,and (3) quantifying the correlations between the characteristics of their solar sources with a maximum value of the Kp-index that is caused by the concerned type of SW stream. Semi-phenomenological relations have been obtained, which relate parameters of type SW stream sources to characteristics of geomagnetic storms:storm commencement, the time at which the storm intensity reaches its maximum values, the storm duration,as well as to the storm amplitude expressed in terms of geomagnetic indeces.
Microwave Brightness Temperature and Lunar Son Dielectric Property Retrieve
J. Wu, D.H. Li, A.T. Altyntsev, B.I. Lubyshev
2005, 25(5): 362-367. doi: 10.11728/cjss2005.05.362
Abstract:
Among many scientific objectives of lunar exploration, investigations on lunar soil become more and more attractive to the scientists duo to the existence of abundant 3He and ilmenite in the lunar soil and their possible utilization. Although the soil composition determination on the lunar surface is available by visible light spectrometer, γ/X-ray spectrometer etc, the evaluations on the total reserves of 3He and ilmenite in the lunar deep and on the thickness of the lunar soil are still impossible so far. In this paper, the authors first give a rough analysis of the microwave brightness temperature images of the lunar disc observed using the NRAO 12 Meter Telescope and Siberian Solar Radio Telescope; then introduce our researches on the microwave dielectric properties of lunar soil simulators; finally, discuss some basic relations between the microwave brightness temperature and lunar soil properties.
Magnetic Field Fluctuations in the Solar Wind, Foreshock and Magnetosheath: Cluster Data Analysis
J. Du, C. Wang, X.X. Zhang, N.N. Shevyre, G.N. Zastenker
2005, 25(5): 368-373. doi: 10.11728/cjss2005.05.368
Abstract:
46 magnetosheath crossing events from the two years (2001.2-2003.1) of Cluster magnetic field measurements are identified and used to investigate the characters of the magnetic field fluctuations in the regions of undisturbed solar wind, foreshock, magnetosheath. The preliminary results indicate the properties of the plasma turbulence in the magnetosheath are strongly controlled by IMF orientation with respect to the bow shock normal. The amplitude of the magnetic field magnitude and direction variations behind quasiparallel bow shock are larger than those behind quasi-perpendicular bow shock. Almost purely compressional waves are found in quasi-perpendicular magnetosheath.
Prediction of Magnetospheric Disturbances Caused by a Quasi-Stationary Solar Wind
V. G. Eselevich, M.V. Eselevich
2005, 25(5): 374-382. doi: 10.11728/cjss2005.05.374
Abstract:
When predicting parameters of quasi-stationary Solar Wind (SW) streams at 1 AU, it is customary to use, as the indicator of solar sources, the Bases of Open Magnetic Tubes (BOMT) on the solar surface obtained via a calculation relying on a new Bd-technique of harmonic expansion of the magnetic field from daily full-disk magnetograms developed by Rudenko[4]. By considering an example of 17 events, it is shown that the correspondence between fast SW streams at the Earth's orbit and the BOMT, calculated with ≤ 24 h time resolution, makes up about 94%, while the correspondence of SW stereams with the CH in the light of the 10830 A line is about 29%. With this technique, the predictability of maxima of the Kp index of magnetospheric disturbance caused by a fast quasi-stationary SW, is over 90%, and the prediction accuracy of the maximun velocity vm of the stream is ±15%.
Study of the Enhancement Events of Relativistic Electron at the Geosynchronous Orbit
B. S. Xue
2005, 25(5): 383-386. doi: 10.11728/cjss2005.05.383
Abstract:
The high flux of energetic electron on geostationary orbit can induce many kinds of malfunction of the satellite there, within which the bulk-charging is the most significant that several broadcast satellite failures were confirmed to be due to this effect. The electron flux on geostationary orbit varies in a large range even up to three orders accompanied the passage of interplanetary magnetic cloud and the following geomagnetic disturbances. Upon the investigation of electron flux enhancement events, two types of events were partitioned as recurrent events and random ones. Both of the two kinds of events relate to the interplanetary conditions such as solar wind parameters, IMF etc and their evolution characters as well. As for the recurrent events, we found that, (1) all of the events exhibits periodic recurrence about 27 days, (2) significant increase of electron flux relates to interplanetary index and characters of their distribution, (3) the electron flux also has relation to solar activity index. An artificial neural network was constructed to estimate the flux I day ahead. The random electron flux enhancement events are rare and present different distribution figures to the recurrent ones. The figure of the random events and the conditions of their occurrence is also discussed in this paper.
Variations of the Magnetosphere Resonance Frequencies During Magnetic Storm of July 15——16, 2000
A. Potapov, A. Polyakov, T. Polyushkina, H. Zhao
2005, 25(5): 387-392. doi: 10.11728/cjss2005.05.387
Abstract:
ULF observations at two mid-latitude sites during the large geomagnetic storm of July 15-16,2000 were used to trace variations of resonance frequencies of the field line resonators. A brief description of the geomagnetic disturbance as it was observed on the ground, at the geostationary orbit, and before the Earth's bow shock is given. Then a detailed study of ULF dynamic spectra from Borok and Mondy is performed for8 succesive 6-hour intervals of July 15 and 16. In conclusion some tasks for the future work are listed.
Pc5 Oscillation Analysis by the Satellite and Ground-Based Data
A. Potapov, T. Polyushkina, T. L. Zhang, H. Zhao, A. Guglielmi, J. Kultima
2005, 25(5): 393-396. doi: 10.11728/cjss2005.05.393
Abstract:
Large amplitude Pc5 event was observed in the space and on ground on August 3, 2001, about three hours after contact of the strong discontinuity in the solar wind with the magnetosphere according to data from ACE and Wind satellites. The Pc5 amplitude was as high as 15 nT in the tail of magnetosphere and about 5 nT at the ground based stations. In the magnetosphere Pc5 waves were observed by Cluster and Polar satellites, which occupied positions in the morning part of the near tail at the close field lines but were parted by distance of 11.5 Re, mainly along the x-axis of the GSM coordinate system. Both compressional and transverse components of the Pc5 wave activity were observed in the space, with the transverse component having the larger amplitude. Time delay between the Cluster and Polar satellites was about 8 minutes, which could be interpreted as a wave propagation from the geomagnetic tail to the Earth with the 150km/s group velocity.The ground-based Pc5 activity was analysed by using data from the Image magnetometer network. Doubtless demonstrations of a field line resonant structure were found in variations of amplitude and polarization with latitude. Finnish chain of search coil magnetometers observed modulated Pc1 emission simultaneously with the Pc5 wave train. A possibility of non-linear impact of Pc5 wave energy on the plasma and waves in the magnetosphere is discussed.
From the Solar Wind to the Magnetospheric Substorm
E.A. Ponomarev, P.A. Sedykh, O.V. Mager
2005, 25(5): 397-405. doi: 10.11728/cjss2005.05.397
Abstract:
This paper gives a brief outline of the progression from the first substorm model developed in Ref.[4] and
[8] based on Kennel's ideas[3], to the present views about the mechanism by which solar wind kinetic energy is converted to electromagnetic energy at the Bow Shock and by which this energy is transferred to the magnetosphere in the form of current; about the transformation of the energy of this current to gas kinetic energy of convecting plasma tubes, and, finally, the back transformation of gas kinetic energy to electromagnetic energy in secondary magnetospheric MHD generators. The questions of the formation of the magnetospheric convection system, the nature of substorm break-up, and of the matching of currents in the magnetosphere-ionosphere system are discussed.
Mid-Latitude Pc1, 2 Pulsations Induced by Magnetospheric Compression in the Maximum and Early Recovery Phase of Geomagnetic Storms
N. A. Zolotukhina, I.P. Kharchenko
2005, 25(5): 406-411. doi: 10.11728/cjss2005.05.406
Abstract:
We investigate the properties of interplanetary inhomogeneities generating long-lasting mid-latitude Pc1, 2 geomagnetic pulsations. The data from the Wind and IMP 8 spacecrafts, and from the Mondy and Borok midlatitude magnetic observatories are used in this study. The pulsations under investigation develop in the maximum and early recovery phase of magnetic storms. The pulsations have amplitudes from a few tens to several hundred pT andlast more than seven hours. A close association of the increase (decrease) in solar wind dynamic pressure (Psw) with the onset or enhancement (attenuation or decay) of these pulsations has been established. Contrary to high-latitude phenomena, there is a distinctive feature of the interplanetary inhomogeneities that are responsible for generation of long-lasting mid-latitude Pc1, 2. It is essential that the effect of the quasi-stationary negative Bz-component of the interplanetary magnetic field on the magnetosphere extends over 4 hours. Only then are the Psw pulses able to excite the above-mentioned type of mid-latitude geomagnetic pulsations. Model calculations show that in the cases under study the plasmapause can form in the vicinity of the magnetic observatory. This implies that the existence of an intense ring current resulting from the enhanced magnetospheric convection is necessary for the Pc1, 2 excitation. Further, the existence of the plasmapause above the observation point (as a waveguide) is necessary for long-lasting Pc1 waves to arrive at the ground.
A Theoretic Interpretation of Movement of the Cusp Equatorward Boundary
J. B. Cao, A. Leonovich, G.C. Zhou, Z.X. Liu, H. Reme, I. D, ouras
2005, 25(5): 412-418. doi: 10.11728/cjss2005.05.412
Abstract:
A preliminary model is proposed to describe quantitatively the position and movement of cusp equatorward boundary. This integrated model, consisting of an empirical model of the magnetopause and a compressed dipolar model of Open/Closed field line, connects quantitatively the solar wind conditions, subsolar magnetopause and cusp equatorward boundary. It is shown that the increasing solar wind dynamic pressure and the increasing southward Interplanetary Magnetic Field (IMF) component drive the magnetopause to move inward and the cusp equatorward. This model is adopted to interpret quantitatively the cusp movement of August 14, 2001 observed by Cluster. The results show that the subsolar magnetopause moved earthward from 10.7 Re to 9.0Re during the period of 002300-002800 UT, and correspondingly the cusp equatorward boundary shifted equatorward. The observations of Cluster C1 and C4 show the cusp equatorward boundary that Cluster C1 and C4 were crossing during same interval moved equatorward by 4.6°. The cusp equatorward boundary velocity computed in the theoretical model (10.7 km/s) is in good agreement with the observed value(9.4km/s) calculated from the data of CIS of Cluster C4 and C1.
Some Properties of Microwave Emission From Flaring Regions
V. R. Maksimov, V.L. Shchepkina, E.A. Chernova
2005, 25(5): 419-423. doi: 10.11728/cjss2005.05.419
Abstract:
A study is made of the differences in the polarization distribution and other characteristics of microwave emission for several active regionswith high flare productivity. Conclusions are drawn about the magnetic field structure of these regions at coronal heights.
Input Parameters for Models of Energetic Electrons Fluxes at the Geostationary Orbit
V. I. Degtyarev, G.V. Popov, B. S. Xue, S.E. Chudnenko
2005, 25(5): 424-429. doi: 10.11728/cjss2005.05.424
Abstract:
The results of cross-correlation analysis between electrons fluxes (with energies of > 0.6 MeV,> 2.0MeV and > 4.0MeV), geomagnetic indices and solar wind parameters are shown in the paper. It is determined that the electron fluxes are controlled not only by the geomagnetic indices, but also by the solar wind parameters, and the solar wind velocity demonstrates the best relation with the electron fluxes.Numerical value of the relation efficiency of external parameters with the highly energetic electrons fluxes shows a periodicity. It is presented here the preliminary results of daily averaged electrons fluxes forecast for a day ahead on the basis of the model of neuron networks.
An Investigation of Near-Equatorial Geomagnetic Pi2 Pulsations
A. Y. Pashinin, R.A. Rakhmatulin, H. Zhao
2005, 25(5): 430-432. doi: 10.11728/cjss2005.05.430
Abstract:
There is understanding to date that Pi2 pulsations have two sources. One source is a high-latitude one and is due to fluctuations of electro jet parameters. The other source is a mid-latitude one and is driven by a global mode excited in the Earths plasmasphere. There is experimental evidence that in the nearequatorial regions the character of Pi2 excitation is different from high and mid-latitudes. In this connection,we investigated the amplitude-spectral-polarization characteristics of Pi2 pulsations using the date from nearequatorial Chinese stations. The detected regularities in the excitation of near-equatorial Pi2 pulsations are used in the discussion of the possible physical mechanism that is responsible for the generation of these pulsations.
Superlow-Frequency MHD-Eigenoscillations With a Discrete Spectrum in Parabolic Model of Magnetosphere
A. S. Leonovich, V.A. Mazur
2005, 25(5): 433-435. doi: 10.11728/cjss2005.05.433
Abstract:
A new concept of the global magnetospheric resonator is suggested for fast magnetosonic waves in which the role of the resonator is played by the near part of the plasma sheet. It is shown that the magnetosonic wave is confined in this region of the magnetosphere throughout its boundaries. The representative value of the resonator's eigenfrequency estimated at f ≈ 1 mHz is in good agreement with observational data on ultraThe theory explains the ground-based localization of the oscillations observed in the midnight-morning sector of the high-latitude magnetosphere.
Space Weather Parameters Computed on the Basis of the Magnetogram Inversion Technique
V. M. Mishin, M. F(o)rster, A.D. Bazarzhapov, T.I. Saifudinova, Y.A. Karavaev, P. Stauning, J. Watermann, V. Golovkov, S. Solovyev
2005, 25(5): 436-446. doi: 10.11728/cjss2005.05.436
Abstract:
In this paper is given short description of the magnetogram inversion technique, MIT2, and of methods of calculation of some parameters of space weather. Are given also examples of new results, obtained using the MIT2 and solar wind data.
Influence of the Ionosphere on the Observation of the Mid-Latitude Pi2 Pulsations at the Global Scale
R. A. Rakhmatulin, A.Y. Pashinin
2005, 25(5): 447-449. doi: 10.11728/cjss2005.05.447
Abstract:
Results of our investigation showed that occurrence frequency of Pi2 over a 24 hour period undergoes seasonal variations in time coincidence with foF2. In the winter months, at sunrise and sunset (when foF2gradients are the largest) the observation probability of these oscillations is minimal. At periods of summer solstice when the F2-layer persists almost round the clock, no effect of Pi2 pulsation attenuation is observed at sunrise and sunset. The pulsation amplitudes behave in a similar manner. Results of this study suggest the conclusion that the propagation of signal from the Pi2 sourse into the mid-latitudes, and also the parameters of these pulsations are essentially affected by electron density in the ionospheric F2-layer.
A Mechanism of Solar Variability Effect on Radiative Balance of the Earth Atmosphere
G. A. Zherebtsov, V.A. Kovalenko, S.I. Molodykh
2005, 25(5): 450-459. doi: 10.11728/cjss2005.05.450
Abstract:
Possible mechanisms of solar-climatic connections, which may be of importance as over short and long time intervals, are discussed. The variations of energetic balance of Earth's climatic system for the last fifty years are estimated. It is ascertained that the disbalance between the flux of solar energy that comes to the Earth and radiates to space is of 0.1% for the last ten years. The suggested mechanism makes it possible to explain not only the observed variation of the enthalpy of the Earth's climatic system for the period 1910-1980, but also the climate anomalies during last thousand years: the climate optimum in 12 century, and"small glacial period" in 16-17 centuries.
Influence of Fast Global Variations of Solar Magnetic Fields on Space Weather in Cycle 23
S. I. Molodykh, G.A. Zherebtsov, V.A. Kovalenko, J.X. Wang, V.I. Sidorov
2005, 25(5): 460-467. doi: 10.11728/cjss2005.05.460
Abstract:
It is established that the large-scale and global magnetic fields in the Sun's atmosphere do not change smoothly, and long-lasting periods of gradual variations are superseded by fast structural changes of the global magnetic field. Periods of fast global changes on the Sun are accompanied by anomalous manifestations in the interplanetary space and in the geomagnetic field. There is a regular recurrence of these periods in each cycle of solar activity, and the periods are characterized by enhanced flaring activity that reflects fast changes in magnetic structures. Is demonstrated, that the fast changes have essential influencing on a condition of space weather, as most strong geophysical disturbances are connected to sporadic phenomena on the Sun. An explanation has been offered for the origin of anomalous geomagnetic disturbances that are unidentifiable in traditionally used solar activity indices. Is shown, main physical mechanism that leads to fast variations of the magnetic fields in the Sun's atmosphere is the reconnection process.
Ionospheric Effects of Geomagnetic Storms in Different Longitude Sectors
G. A. Zherebtsov, O.M. Pirog, N.M. Polekh
2005, 25(5): 468-473. doi: 10.11728/cjss2005.05.468
Abstract:
This paper analyzes the state of the ionosphere during two geomagnetic storms of a different intensity evolving in different sectors of local time in different seasons. There were used the data from a network of ionospheric stations located in the opposite longitudinal sectors of 80°-150° E and 250°-310° E.This analysis has permitted us to conclude that the detected differences in the variations of the disturbances are likely to be determined by the local time difference of the geomagnetic storm development, its intensity and by the different illumination conditions of the ionosphere.
Solar Activity and the Climate of Prebaikalia
V. A. Kovalenko, G.A. Zherebtsov, S.I. Molodykh
2005, 25(5): 474-477. doi: 10.11728/cjss2005.05.474
Abstract:
This paper presents convincing evidence for the reality of manifestations of solar variability in climate characteristics of the Prebaikalia. A numerical estimate is obtained of this influence on ground air temperature. It is shown that the main meaningful variations in air temperature in the region for the period1881-1960 were caused by solar activity. Since the 1960s till the present, with the influence of solar variability continuing, a clear-cut influence of another factor has been observed, the role of which has been steadily increasing, and in the hst decade it has now exceeded the contribution of solar variability. Research results on the variations in hydrological characteristics of Lake Baikal and the Angara river and their connection with solar activity are presented. It is shown that these characteristics are closely correlated with the duration of solar cycles.
Modelling of Geomagnetic Storm Effects in the Ionosphere of East Asia
G. A. Zherebtsov, O.M. Pirog, N.M. Polekh, E. B. Romanova, A.V. Tashchilin
2005, 25(5): 478-483. doi: 10.11728/cjss2005.05.478
Abstract:
This paper presents simulated results of the ionospheric behavior during few geomagnetic storms,which were occurred in the different seasons. The numerical model for ionosphere-plasmasphere coupling was used to interpret the observed variation of ionosphere structure. Reasons why the positive storms are dominant in the winter whereas the negative ones are dominant in the summer season present the special interest for the mid-latitude ionosphere. A theoretical analysis of the processes controlling the ionospheric response to the geomagnetic storms has showed a good agreement between the simulated results and measurements, as well as the crucial role of the neutral composition variations to fit the calculated and the observed ionospheric parameters.
A Method of Inversing the Peak Density of Atomic Oxygen Vertical Distribution in the MLT Region From the OI (557.7nm) Night Airglow Intensity
H. Gao, J.Y. Xu, W. Yuan
2005, 25(5): 484-489. doi: 10.11728/cjss2005.05.484
Abstract:
In this paper, using the MSISE-90 model as the reference atmosphere, we discuss the feasibility and method of deducing the peak densities of the undisturbed atomic oxygen profiles in the MLT region (the mesosphere and lower thermosphere region) from OI (557.7 nm) night airglow intersities. The peak densities for different seasons, latitudes and longitudes are deduced from OI (557.7nm) airglow intensities through this expression. We analyze the features of inversion relative errors and discuss the influence of the variations in temperature on inversion errors. The results indicate that all inversion errors are less than 5% except for those at high altitudes in the summer hemisphere. And the impact of the variations in temperature on errors is not significant.
The Nonlinear Model of the Response of Airglow to Gravity Waves
J. Y. Xu, H. Gao, A.V. Mikhalev
2005, 25(5): 490-490. doi: 10.11728/cjss2005.05.490
Abstract:
In this paper, we develope a timodependent, nonlinear, photochemical-dynamical 2-D model which is composed of 3 models: dynamical gravity wave model, middle atmospheric photochemical model, and airglow layer photochemical model. We use the model to study the effect of the gravity wave propagation on the airglow layer. The comparison between the effects of the different wavelength gravity wave on the airglow emission distributions is made. When the vertical wavelength of the gravity wave is close to or is shorter than the thickness of the airglow layer, the gravity wave can make complex structure of the airglow layer, such as the double and multi-peak structures of the airglow layer. However, the gravity wave that has long vertical wavelength can make large scale perturbation of the airglow emission distribution.