Modelling of the Lower Ionosphere

Смирнова, Н. В.; Ogloblina, O. F.; Vlaskov, V. A.

doi:10.1007/978-3-0348-6532-6_8

Cited by 3 publications

(9 citation statements)

References 21 publications

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“…The variations of each of these radiations with the solar activity present a special problem, which is outside the scope of this paper. We present here the most reliable (in our opinion) values of these variations used by Smirnova et al (1984Smirnova et al ( , 1988 to evaluate the eects expected in the D region. Table 5.…”

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 81%

“…Table 5. Values of r according to the theoretical model by Smirnova et al (1984Smirnova et al ( , 1988 The Lyman-alpha intensity grows from minimum to maximum of the solar activity by 1.7 times. The intensity of the radiation within the 111.8±102.7-nm interval increases by a factor of 2.…”

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

“…Nonetheless, D-region theoretical models, which describe the principal links of the foregoing schemes with various degree of reliability, have been created. Here we consider brie¯y the possible relation of [e] to the solar activity on the basis of the theoretical D-region model by Smirnova et al (1984Smirnova et al ( , 1988.…”

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

“…According to current ideas, NO, the principal ionized constituent in the upper part of the D region, shows no signi®cant variations with F(10.7). As for the minor constituents, which play important roles in the lower D region, still only little is known regarding their variations, thus, as a ®rst approximation, they were taken independently of solar activity in evaluating the r values (Smirnova et al, 1984(Smirnova et al, , 1988.…”

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

“…Radio-wave propagation Bremer and Singer (1977) 1.2 1.3 1.4 1.2 6. Theoretical models Smirnova et al (1984Smirnova et al ( , 1988 0.9 0.9 1.1 1.5 75±150…”

Section: Introductionmentioning

confidence: 99%

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Solar activity effects in the ionospheric D region

Данилов

1998

Ann. Geophys.

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Abstract. Variations in the D-region electron concentration within the solar activity cycle are considered. It is demonstrated that conclusions of various authors, who have analyzed various sets of experimental data on [e], differ significantly. The most reliable seem to be the conclusions based on analysis of the [e] measurements carried out by the Faraday rotation method and on the theoretical concepts on the D-region photochemistry. Possible QBO effects in the relation of [e] to solar activity are considered and an assumption is made that such effects may be the reason for the aforementioned disagreement in conclusions on the [e] relation to solar indices.Key words. Atmospheric composition and structure · Ion chemistry of the atmosphere · Middle atmosphere

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Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 81%

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

Section: Theoretical Concepts Of the [E] Relation To Solar Activitymentioning

confidence: 99%

“…Radio-wave propagation Bremer and Singer (1977) 1.2 1.3 1.4 1.2 6. Theoretical models Smirnova et al (1984Smirnova et al ( , 1988 0.9 0.9 1.1 1.5 75±150…”

Section: Introductionmentioning

confidence: 99%

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Solar activity effects in the ionospheric D region

Данилов

1998

Ann. Geophys.

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Electron density profiles in the quiet lower ionosphere based on the results of modeling and experimental data

et al. 2012

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Abstract. The theoretical PGI (Polar Geophysical Institute) model for the quiet lower ionosphere has been applied for computing the ionization rate and electron density profiles in the summer and winter D-region at solar zenith angles less than 80 • and larger than 99 • under steady state conditions. In order to minimize possible errors in estimation of ionization rates provided by solar electromagnetic radiation and to obtain the most exact values of electron density, each wavelength range of the solar spectrum has been divided into several intervals and the relations between the solar radiation intensity at these wavelengths and the solar activity index F 10.7 have been incorporated into the model. Influence of minor neutral species (NO, H 2 O, O, O 3 ) concentrations on the electron number density at different altitudes of the sunlit quiet D-region has been examined. The results demonstrate that at altitudes above 70 km, the modeled electron density is most sensitive to variations of nitric oxide concentration. Changes of water vapor concentration in the whole altitude range of the mesosphere influence the electron density only in the narrow height interval 73-85 km. The effect of the change of atomic oxygen and ozone concentration is the least significant and takes place only below 70 km.Model responses to changes of the solar zenith angle, solar activity (low-high) and season (summer-winter) have been considered. Modeled electron density profiles have been evaluated by comparison with experimental profiles available from the rocket measurements for the same conditions. It is demonstrated that the theoretical model for the quiet lower ionosphere is quite effective in describing variations in ionization rate, electron number density and effective recombination coefficient as functions of solar zenith angle, solar activity and season. The model may be used for solving inverse tasks, in particular, for estimations of nitric oxide concentration in the mesosphere.

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Ionization and NO production in the polar mesosphere during high-speed solar wind streams: model validation and comparison with NO enhancements observed by Odin-SMR

et al. 2015

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Abstract. Precipitation of high-energy electrons (EEP) into the polar middle atmosphere is a potential source of significant production of odd nitrogen, which may play a role in stratospheric ozone destruction and in perturbing large-scale atmospheric circulation patterns. High-speed streams of solar wind (HSS) are a major source of energization and precipitation of electrons from the Earth's radiation belts, but it remains to be determined whether these electrons make a significant contribution to the odd-nitrogen budget in the middle atmosphere when compared to production by solar protons or by lower-energy (auroral) electrons at higher altitudes, with subsequent downward transport. Satellite observations of EEP are available, but their accuracy is not well established. Studies of the ionization of the atmosphere in response to EEP, in terms of cosmic-noise absorption (CNA), have indicated an unexplained seasonal variation in HSS-related effects and have suggested possible order-ofmagnitude underestimates of the EEP fluxes by the satellite observations in some circumstances. Here we use a model of ionization by EEP coupled with an ion chemistry model to show that published average EEP fluxes, during HSS events, from satellite measurements (Meredith et al., 2011), are fully consistent with the published average CNA response (Kavanagh et al., 2012). The seasonal variation of CNA response can be explained by ion chemistry with no need for any seasonal variation in EEP. Average EEP fluxes are used to estimate production rate profiles of nitric oxide between 60 and 100 km heights over Antarctica for a series of unusually well separated HSS events in austral winter 2010. These are compared to observations of changes in nitric oxide during the events, made by the sub-millimetre microwave radiometer on the Odin spacecraft. The observations show strong increases of nitric oxide amounts between 75 and 90 km heights, at all latitudes poleward of 60 • S, about 10 days after the arrival of the HSS. These are of the same order of magnitude but generally larger than would be expected from direct production by HSS-associated EEP, indicating that downward transport likely contributes in addition to direct production.

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Modelling of the Lower Ionosphere

Cited by 3 publications

References 21 publications

Solar activity effects in the ionospheric D region

Solar activity effects in the ionospheric D region

Electron density profiles in the quiet lower ionosphere based on the results of modeling and experimental data

Ionization and NO production in the polar mesosphere during high-speed solar wind streams: model validation and comparison with NO enhancements observed by Odin-SMR

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