International reference ionosphere—Status 1995/96

Bilitza, D.

doi:10.1016/s0273-1177(97)00584-x

Cited by 156 publications

(99 citation statements)

References 14 publications

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“…Figure 8 gives scatter plot IRO hmF2 vs. LogNmF2 for all analyzed cases in a comparison with the IRI-95 (Bilitza 1997) monthly median model values calculated for the same IRO experiments. For solar minimum similar to Figure 7 all cases which did not give a solution occupy the lower part of the plot manifesting very low hmF2 while there are no points in IRI with hmF2 200 km.…”

Section: Assessment Of the Resultsmentioning

confidence: 99%

On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

Михайлов

Belehaki

Perrone

et al. 2014

J. Space Weather Space Clim.

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This paper investigates possible use of middle latitude daytime COSMIC and CHAMP ionospheric radio occultation (IRO) electron density profiles (EDPs) to retrieve thermospheric parameters, based on the Mikhailov et al. (2012) method. The aim of this investigation is to assess the applicability of this type of observations for the routine implementation of the method. According to the results extracted from the analysis presented here, about half of COSMIC IRO EDP observed under solar minimum (2007)(2008) conditions gave neutral gas density with an inaccuracy close to the declared absolute inaccuracy ±(10-15)% of CHAMP observations, with the results being better than the empirical models JB-2008 and MSISE-00 provide. For the other half of IRO EDP, either the solution provided by the method had to be rejected due to insufficient accuracy or no solution could be obtained. For these cases, the parameters foF2 and hmF2 extracted from the corresponding IRO profiles have been found to be inconsistent with the classic mid-latitude daytime F2-layer formalism that the method relies on, and they are incompatible with the general trend provided by the IRI model. For solar maximum conditions (2002) the method was tested with IRO EDP from CHAMP and it is indicated that its performance is quite stable in the sense that a solution could be obtained for all the cases analyzed here. However available CHAMP EDP are confined by~400 km in altitude and this might be the reason for the 20% bias of the retrieved densities toward larger values in respect to the observed densities. IRO observations up to 600 km under solar maximum are required to confirm the exact performance of the method.

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Section: Assessment Of the Resultsmentioning

confidence: 99%

On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

Михайлов

Belehaki

Perrone

et al. 2014

J. Space Weather Space Clim.

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“…This gives V Am ≈870 km/s, sin I ≈0.9. For these conditions L≈210 km, if the estimations are based on the IRI model (Bilitza, 1997). Substitution of these values into Eqs.…”

Section: Discussionmentioning

confidence: 99%

“…Figure 1a shows the altitude distribution (along the geomagnetic field) of the Alfvén wave refractive index n A =c/V A obtained using the IRI model (Bilitza, 1997) for medium solar activity -a relative sunspot number W =70, middle latitudes -an L-shell equal to 1.8, in February, at midnight. The analytical approximation of n A altitude distribution for the F2-layer, where O + ions dominate, is…”

Section: Geophysical Conditionsmentioning

confidence: 99%

Dynamics of Alfvén waves in the night-side ionospheric Alfvén resonator at mid-latitudes

Alpatov

Dëminov²,

Faermark³

et al. 2005

Ann. Geophys.

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Abstract.A numerical solution of the problem on dynamics of shear-mode Alfvén waves in the ionospheric Alfvén resonator (IAR) region at middle latitudes at nighttime is presented for a case when a source emits a single pulse of duration τ into the resonator region. It is obtained that a part of the pulse energy is trapped by the IAR. As a result, there occur Alfvén waves trapped by the resonator which are being damped. It is established that the amplitude of the trapped waves depends essentially on the emitted pulse duration τ and it is maximum at τ =(3/4)T , where T is the IAR fundamental period. The maximum amplitude of these waves does not exceed 30% of the initial pulse even under optimum conditions. Relatively low efficiency of trapping the shear-mode Alfvén waves is caused by a difference between the optimum duration of the pulse and the fundamental period of the resonator. The period of oscillations of the trapped waves is approximately equal to T , irrespective of the pulse duration τ . The characteristic time of damping of the trapped waves τ dec is proportional to T , therefore the resonator Q-factor for such waves is independent of T . For a periodic source the amplitude-frequency characteristic of the IAR has a local minimum at the frequency π/ω=(3/4)T , and the waves of such frequency do not accumulate energy in the resonator region. At the fundamental frequency ω=2π /T the amplitude of the waves coming from the periodic source can be amplified in the resonator region by more than 50%. This alone is a basic difference between efficiencies of pulse and periodic sources of Alfvén waves. Explicit dependences of the IAR characteristics (T , τ dec , Q-factor and eigenfrequencies) on the altitudinal distribution of Alfvén velocity are presented which are analytical approximations of numerical results.

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“…At summer solar minimum, however, this transition altitude can lie well above 180 km. For Millstone Hill at 250 km the latest version of the International Reference Ionosphere (IRI-95) (Bilitza, 1997) gives 47% molecular ions at noon and 58% at midnight.…”

Section: Correction Of Incoherent Scatter Radar Data Using the Izmiramentioning

confidence: 99%

Anomalous electron density events in the quiet summer ionosphere at solar minimum over Millstone Hill

Павлов

Buonsanto

1998

Ann. Geophys.

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Abstract. This study compares the observed behavior of the F region ionosphere over Millstone Hill with calculations from the IZMIRAN model for solar minimum for the geomagnetically quiet period 23±25 June 1986, when anomalously low values of hmp 2`200 km) were observed. We found that these low values of hmp 2 (seen as a G condition on ionograms) exist in the ionosphere due to a decrease of production rates of oxygen ions resulting from low values of atomic oxygen density. Results show that determination of a G condition using incoherent scatter radar data is sensitive both to the true concentration of O relative to the molecular ions, and to the ion composition model assumed in the data reduction process. The increase in the O N 2 loss rate due to vibrationally excited N 2 produces a reduction in xmp 2 of typically 5±10% , but as large as 15% , bringing the model and data into better agreement. The eect of vibrationally excited NO ions on electron densities is negligible.

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International reference ionosphere—Status 1995/96

Cited by 156 publications

References 14 publications

On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

Dynamics of Alfvén waves in the night-side ionospheric Alfvén resonator at mid-latitudes

Anomalous electron density events in the quiet summer ionosphere at solar minimum over Millstone Hill

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