Showing papers in "Journal of Atmospheric and Solar-Terrestrial Physics in 1997"

TL;DR: In this paper, the authors investigated the global cloud cover observed by satellites and found that the observed variation of 3-4% of the cloud cover during the recent solar cycle is strongly correlated with the cosmic ray flux.

TL;DR: In this paper, the authors extended the parameterization developed in its companion paper, Part 1, and discussed the input vertical-wavenumber spectrum of the broad background of gravity waves that Part 1 is designed to treat.

TL;DR: In this article, a review of recent results related to the response of the major phenomena of the equatorial ionosphere-thermosphere system (EITS) to magnetospheric disturbances is presented.

TL;DR: In this article, the authors examined the present understanding of low-latitude F-region electrodynamics focusing on the large-scale distribution of the ionospheric electric fields and their response to magnetospheric disturbances.

TL;DR: The Sheffield University plasmasphere ionosphere model (SUPIM) as discussed by the authors was proposed to solve time-dependent equations of continuity, momentum, and energy balance along eccentric-dipole magnetic field lines for the densities, field-aligned fluxes and temperatures of the O +, H +, He +, N 2 +, O 2 + and NO + ions.

TL;DR: In this paper, features of artificial small-scale ionospheric irregularities (ASI) induced at F-region heights by powerful HF waves are discussed, and the temporal evolution of ASI spectral characteristics during the heater period is discussed.

TL;DR: In this paper, both the observational and theoretical studies of polar cap arcs are reviewed, which are the arcs that occur in the polar cap or in the poleward regions of the auroral oval.

TL;DR: In this paper, the "disturbed/quiet" ratio of the peak electron density NmF2 is expressed in terms of "mean" and "local time" variations for over 20 years' data from each of 53 stations between 70 °N and 80 °S.

TL;DR: In this article, ground-based observations of the wind field in the mesosphere/lower thermosphere have been used to investigate long-lasting wind variations at mid-latitudes.

TL;DR: In this paper, the physics of electric currents generated by dynamo action in the ionosphere are discussed, including the motions of ions and electrons relative to the neutral air, at different heights in ionosphere, the voltage generator and current generator aspects of the ionospheric dynamos, electrical coupling along field lines, and the effects of field-aligned currents.

TL;DR: In this paper, the authors investigated the role of geomagnetic disturbances in low-latitude dynamics, electrodynamics, and plasma density structure in the formation of the equatorial ionization anomaly.

TL;DR: In this paper, an analysis of intraseasonal (10-100 days) oscillations in the equatorial mesosphere and lower thermosphere (MLT) is presented, based on over five years of velocity data acquired by a radar system at Christmas Island (2 °N, 157 °W), in the central Pacific.

TL;DR: In this paper, the authors measured perturbations of electron density in the ionosphere caused by a ground level explosion with an energy release of 2 kt (8.5 × 10 12 J) using transmissions from GPS satellites to monitor integrated electron density.

TL;DR: In this paper, the authors used the cosmos-1809 satellite data on ELF emissions, plasma density, Ne and variations dNe in the ionosphere above the Spitak earthquake zone during a period of enhanced aftershock activity.

TL;DR: In this paper, the authors investigate the determination of the kinetic energy dissipation rate e in the middle and upper troposphere by measurements of the refractivity structure function constant Cn2.

TL;DR: In this paper, the propagation characteristics of non-migrating diurnal tides are investigated numerically using a 2-dimensional (latitude-height) steady state model for a realistic atmosphere characterized by background mean zonal winds, meridional temperature gradients, mechanical and thermal dissipation, and tropospheric forcing obtained from a General Circulation Model.

TL;DR: In this article, a large database of hourly ionosonde measurements, encompassing more than 20 stations during 1957-1991, is examined for evidence of the quasi-two-day (QTD) oscillation.

TL;DR: In this article, the authors studied the characteristics of specular echoes reflected from stratified layers in the troposphere and lower stratosphere and observed echoes at antenna-beam zenith angles, θ, from 0 ° to 28 ° in steps of 2 °.

TL;DR: In this article, the effects of hot plasma pressure gradients in the high-latitude magnetosphere are analyzed and it is shown that such a mechanism may in fact be responsible for Region 1 field-aligned currents and for the dawn-dusk electric field.

TL;DR: In this article, modern aspects of the Schumann resonance studies are discussed based on numerical simulations of the ELF radio signals, which provide valuable information on the properties of the lower ionosphere together with the characteristics of planetary lightning activity.

TL;DR: In this article, the superposed epoch method was used to analyze atmospheric electric potential gradient data in Hungary (covering about three decades) at times of Forbush decrease events and found that the potential gradient showed, on average, a minimum on the key days if two lists defined an event on the same day.

TL;DR: In this article, a detailed numerical investigation of the two-frequency coherence function for HF wave propagation in the fluctuating ionosphere is presented, and the results show that the coherence functions in general have a rather complicated behaviour and that it does not fall off quickly with increasing difference frequency.

TL;DR: In this article, the energy distribution function of fast nitrogen atoms from a direct numerical solution of the Boltzmann kinetic equation is constructed using quantum mechanically evaluated differential scattering cross sections, and the contributions to the cross sections that arise from the six lowest NO molecular potential curves exhibit a marked dependence on both the energy and the scattering angle.

TL;DR: In this article, the authors describe ways in which these dynamical influences on airglow can be identified, using WINDII O(1 S) daytime data as an example, which allows both the dayglow and nightglow to be included in the discussion.

TL;DR: In this paper, a quantitative relation between the degree of anisotropy of turbulence and prevailing atmospheric conditions is developed to determine whether any particular observation of "specularity" really can be ascribed to anisotropic atmospheric turbulence, or whether a'specular reflection' process is in effect.

TL;DR: In this article, a review of the auroral plasma wave phenomena is given, including primary auroral electron beams, bursts of more field-aligned electrons over a wide energy range, and so-called ion and electron conics.