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The relationship between the critical frequency of the F
2 layer and the atmospheric characteristics has been obtained in a general form. It has been shown that this relation makes
it possible to sufficiently accurately describe the daytime values of foF2 while comparing them with the observed monthly median values. Such comparisons were performed, first, for the data of measurements
in Irkutsk using the DPS-4 digital ionosonde in 2003–2006 and, second, based on the annual variations in the noon foF2 values at 24 stations of the Northern Hemisphere in 1984. The calculations were performed using the MSIS-86 thermospheric
model [Hedin, 1987]. 相似文献
2.
It is convenient to use the semi-empirical model (SEM), developed by the authors earlier and describing the relation of the electron density at heights of the middle ionosphere (120–200 km) to the parameters of the thermosphere and the integral flux of the ionizing solar radiation, to estimate the gas composition characteristics using the data of ionospheric measurements [Shchepkin et al., 2008]. The ratios of the concentrations of oxygen atoms and nitrogen molecules to those of oxygen molecules and atoms at a height of 120 km are compared using two SEM versions. The first version is based on the usage of the coefficients obtained from the measurements of N(h) profiles at Moscow observatory. The electron densities at heights of 120–200 km, obtained at the Institute of Solar-Terrestrial Physics in 2003–2006 using the digisonde, were the experimental data for the second version. 相似文献
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L. A. Shchepkin G. M. Kuznetsova G. P. Kushnarenko K. G. Ratovsky 《Geomagnetism and Aeronomy》2009,49(8):1308-1310
The applicability of the method proposed by Titheridge [1995] to the estimations of the ionization vertical drift velocity
V is studied. The values of the F2-layer maximum height, h
m
F2, obtained from the measurements using the DPS-4 digital ionosonde at Irkutsk (Institute of Solar-Terrestrial Physics) in
2003–2006, are the initial data. The neutral gas parameters were calculated from the [Hedin, 1987] thermospheric model. The
obtained calculations of the vertical ionization drift velocity are estimated by comparing with the [Hedin et al., 1991] empirical
model. In some cases, good agreement with this model has been obtained. However, such agreement is registered not always,
and the cause of such discrepancies is still unclear. The diurnal variations in the vertical ionization drift velocity in
different seasons are also discussed. 相似文献
5.
Three methods for estimating the atomic oxygen density and exospheric temperature using the ionospheric incoherent scatter
measurements have been compared. These methods are based on the usage of the relationship obtained from the energy conservation
equation. They are applicable under the conditions of the atmosphere composed of oxygen atoms and ions. The first method is
based on the regression analysis of finding minimal deviations of the calculated electron densities (N) from the values measured at altitudes of 300–450 km. The second method is based on solving the set of equations of the analytical
expression relating N to ionospheric characteristics. These equations are given for several altitudes. The third method is related to the selection
of such atomic oxygen densities at which the neutral gas temperature remains constant at an altitude above 350 km. All methods
give similar results. The calculations based on the measurements performed at the Irkutsk radar on September 23, 1998, showed
that the atomic oxygen densities at 400 km, estimated using the first and second methods, account for 0.48 of the value predicted
by the MSIS-86 model, and such densities estimated using the third method account for 0.59 of the model value. In this case
the estimated exospheric temperatures are larger than the values obtained using the thermospheric model by 11% for the first
and second methods and by 14% for the third method. 相似文献
6.
It has been tried to develop the method for estimating the ratio of the densities of oxygen atoms (n 1) and nitrogen molecules (n 3) as well as n 1/n 2 and n 2/n 3 (where n 2 is the density of oxygen molecules) at the reference level of the upper thermosphere (120 km), using the data on electron density at altitudes of 120–200 km. This approach is based on an analysis of the semiempirical model (SEM) equation describing the dependence of electron density (N) on the characteristics of the thermospheric neutral gas. The series of the SEM versions [Shchepkin et al., 1997, 2004] was previously developed by the authors of this work. The estimates were performed based on the regular N measurements with the help of a digital ionosonde at ISZF SO RAN, Irkutsk, in 2003–2005. 相似文献
7.
Manifestations of ionospheric disturbances at heights from 120 km to the height h
m of the F2-layer maximum are analyzed. The geomagnetic disturbances on April 5, 12, and 13, 2005, are considered. These disturbances
are characterized by a pronounced synchronous decrease in the electron concentration over the entire indicated height range.
Using the method proposed by the authors, the noontime changes in the relative content of atomic and molecular oxygen at a
height of 120 km are estimated. There are a distinct decrease in the ratio of atomic oxygen and molecular nitrogen concentrations
and an increase in the ratio of oxygen molecule and atom concentrations. 相似文献
8.
V. D. Shchepkin D. I. Vainshtein R. A. Dautov V. M. Vinokurov 《Physics and Chemistry of Minerals》1980,6(4):269-281
Double nuclear magnetic resonance (DNMR) with Jeener's pulsed sequence on proton and fluorine frequencies was used to investigate the electric quadrupole interactions of (i) 23Na in Na2Cd(SO4)2·2H2O, B 2 0 =±218.5±1 kHz, B 2 2 =±98±5 kHz, (ii) of 23Na, which enter the crystal, CaF2: Na+ (0.07 wt. %) B 2 0 =±85.7±0.5 kHz, trigonal position, and (iii) 23Na which are near the foreign atom in NaF:Ca2+ (0.02 wt.%) B 2 0 =±86.7±0.5 kHz, tetragonal position. Some details of DNMR experiments are analyzed. The conditions for maximum transfer of a Zeeman energy to a dipole-dipole reservoir are described for multispin systems and some crystal hydrates. The angular dependence of the Hamiltonian containing the spherical tensor operators of second rank was obtained for all possible orientations of a local coordinate system relative to a laboratory system. 相似文献
9.
The results of comparison of model calculations of the electron concentration N at ionospheric heights of 120–200 km to the experimental data obtained at a series of geographic points at various levels
of solar activity in various seasons of the year in quiet and disturbed conditions are presented and discussed. The calculations
are performed using the semiempirical model (SEM) developed by the authors and giving in a general form the relation of N to characteristics of the thermospheric neutral gas and the solar activity index. The data presented in the paper show that
the calculations with the SEM in question in the majority of cases agree well with experiment (the difference between them
is 10–20%). The authors believe that the results of the comparative analysis presented in the paper manifest a high degree
of universality of the discussed SEM. 相似文献
10.
Shchepkin L. A. Kuznetsova G. M. Kushnarenko G. P. Ratovsky K. G. 《Geomagnetism and Aeronomy》2009,49(7):1006-1010
Geomagnetism and Aeronomy - The set of the electron concentration (N) measurements at heights of 120–200 km have been generalized using the regression equation from the semi-empirical model... 相似文献
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