Thermospheric meridional winds in the vicinity of the auroral zone: observations and modelling

Leontyev, S.V.; Namgaladze, A. A.; Bogdanov, N. N.

doi:10.1016/s1364-6826(97)00055-2

Cited by 3 publications

(2 citation statements)

References 55 publications

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“…Some recent results obtained by the UAM have been presented by Namgaladze et al (1996Namgaladze et al ( , 1998a, Volkov and Namgaladze (1996), Hall et al (1998), Leontyev et al (1998) and by Korenkov et al (1996a, b) with the GSM TIP model variant with the same generic provenance.…”

Section: The Upper Atmosphere Model Simulationsmentioning

confidence: 88%

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

Namgaladze

Förster

Yurik

2000

Annales Geophysicae

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Abstract. Current theories of F-layer storms are discussed using numerical simulations with the Upper Atmosphere Model, a global self-consistent, time dependent numerical model of the thermosphere±iono-sphere±plasmasphere±magnetosphere system including electrodynamical coupling eects. A case study of a moderate geomagnetic storm at low solar activity during the northern winter solstice exempli®es the complex storm phenomena. The study focuses on positive ionospheric storm eects in relation to thermospheric disturbances in general and thermospheric composition changes in particular. It investigates the dynamical eects of both neutral meridional winds and electric ®elds caused by the disturbance dynamo eect. The penetration of short-time electric ®elds of magnetospheric origin during storm intensi®cation phases is shown for the ®rst time in this model study. Comparisons of the calculated thermospheric composition changes with satellite observations of AE-C and ESRO-4 during storm time show a good agreement. The empirical MSISE90 model, however, is less consistent with the simulations. It does not show the equatorward propagation of the disturbances and predicts that they have a gentler latitudinal gradient. Both theoretical and experimental data reveal that although the ratio of [O]/[N 2 ] at high latitudes decreases significantly during the magnetic storm compared with the quiet time level, at mid to low latitudes it does not increase (at ®xed altitudes) above the quiet reference level. Meanwhile, the ionospheric storm is positive there. We conclude that the positive phase of the ionospheric storm is mainly due to uplifting of ionospheric F 2 -region plasma at mid latitudes and its equatorward movement at low latitudes along geomagnetic ®eld lines caused by large-scale neutral wind circulation and the passage of travelling atmospheric disturbances (TADs). The calculated zonal electric ®eld disturbances also help to create the positive ionospheric disturbances both at middle and low latitudes. Minor contributions arise from the general density enhancement of all constituents during geomagnetic storms, which favours ion production processes above ion losses at ®xed height under daylight conditions.

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Section: The Upper Atmosphere Model Simulationsmentioning

confidence: 88%

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

Namgaladze

Förster

Yurik

2000

Annales Geophysicae

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“…This allows the modeling of the upper atmospheric behavior during substorms via the UAM simulations. The results were presented in [4,[48][49][50][51][52][53] including the cusp and auroral oval behavior, energetic magnetospheric electron precipitations, electric fields, current wedge and internal atmospheric gravity waves generation. The main role of the thermospheric heating due to the soft electron precipitation was shown for the thermosphere substorm effects.…”

Section: Resultsmentioning

confidence: 99%

The Global Numerical Model of the Earth’s Upper Atmosphere

Aleksandr¹,

Maria²,

Карпов³

et al. 2018

Numerical Simulations in Engineering and Science

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The global numerical first principle 3D model of the upper atmosphere (UAM) for the heights 60-100,000 km is presented. The physical continuity, motion, heat balance and electric potential equations for the neutral, ion and electron gases and their numerical solution method are described. The numerical grids, spatial and time integration steps are given together with the boundary and initial conditions and inputs. Testing and obtained geophysical results are given for many observed situations at various levels of solar, geomagnetic and seismic activity.

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Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

Namgaladze

Förster²,

Yurik³

2000

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Current theories of F-layer storms are discussed using numerical simulations with the Upper Atmosphere Model, a global self-consistent, time dependent numerical model of the thermosphere±iono-sphere±plasmasphere±magnetosphere system including electrodynamical coupling e ects. A case study of a moderate geomagnetic storm at low solar activity during the northern winter solstice exempli®es the complex storm phenomena. The study focuses on positive ionospheric storm e ects in relation to thermospheric disturbances in general and thermospheric composition changes in particular. It investigates the dynamical e ects of both neutral meridional winds and electric ®elds caused by the disturbance dynamo e ect. The penetration of short-time electric ®elds of magnetospheric origin during storm intensi®cation phases is shown for the ®rst time in this model study. Comparisons of the calculated thermospheric composition changes with satellite observations of AE-C and ESRO-4 during storm time show a good agreement. The empirical MSISE90 model, however, is less consistent with the simulations. It does not show the equatorward propagation of the disturbances and predicts that they have a gentler latitudinal gradient. Both theoretical and experimental data reveal that although the ratio of [O]/[N 2 ] at high latitudes decreases significantly during the magnetic storm compared with the quiet time level, at mid to low latitudes it does not increase (at ®xed altitudes) above the quiet reference level. Meanwhile, the ionospheric storm is positive there. We conclude that the positive phase of the ionospheric storm is mainly due to uplifting of ionospheric F 2 -region plasma at mid latitudes and its equatorward movement at low latitudes along geomagnetic ®eld lines caused by large-scale neutral wind circulation and the passage of travelling atmospheric disturbances (TADs). The calculated zonal electric ®eld disturbances also help to create the positive ionospheric disturbances both at middle and low latitudes. Minor contributions arise from the general density enhancement of all constituents during geomagnetic storms, which favours ion production processes above ion losses at ®xed height under daylight conditions.

show abstract

Thermospheric meridional winds in the vicinity of the auroral zone: observations and modelling

Cited by 3 publications

References 55 publications

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

The Global Numerical Model of the Earth’s Upper Atmosphere

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

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