Showing papers in "Journal of Atmospheric and Solar-Terrestrial Physics in 1973"

TL;DR: In this paper, physical features of the equatorial electrojet were examined with the aid of a numerical model which includes neutral-air winds and the two-stream instability, and it was found that the model currents and resultant magnetic variations are relatively unaffected by assuming the parallel conductivity, σ 0, to be infinite.

TL;DR: In this paper, the global distribution of variations in the behavior of the electron density of the F2-layer at midday is examined for different levels of solar activity, and it is found that the variations in Nmax can be divided into three major components: winter maximum (seasonal), equinoctial maxima (semi-annual) and a component which peaks in December-January (annual).

TL;DR: An idealized model of the vertical distribution of the electron concentration in the E - and F -regions of the ionosphere is developed in this article, in which the model parameters are given by simple empirical expressions in terms of the characteristics conventionally measured at ionospheric observatories.

TL;DR: By means of non-great-circle propagation on the transequatorial path Lindau-Tsumeb, the equatorial spread-F occurrence in the African area was investigated as discussed by the authors.

TL;DR: In this paper, a review of the techniques and experimental results of measurements of ionospheric drifts and electric fields in the region of the magnetic dip equator is presented. Various techniques are discussed and the results are compared with existing theoretical electric field models.

TL;DR: In this paper, the meridional component of the neutral wind is inferred from the ion velocity component along the magnetic field and simultaneously measured electron density profiles and electron and ion temperatures.

TL;DR: The average diurnal, seasonal and solar cycle changes in the ionosphere from June 1965 to August 1971 were studied in this article, showing that the mean amplitude of the day-to-day fluctuations in electron content shows no appreciable solar cycle change.

TL;DR: In this paper, a global phenomenological model of the large scale variations of ionospheric electron density with the annual, diurnal and solar activity cycles has been constructed from monthly-averaged hourly ionosphere sounding data from some 50 stations spanning the years 1957-1970 as provided by World Data Center (A), Boulder, Colorado.

TL;DR: In this article, a numerical physical model was developed to reproduce the basic features of the observed electrojet, but certain discrepancies suggest that the assumptions of the model or the conductivity distributions used may be inaccurate.

TL;DR: In this paper, the early phases of two magnetic storms were observed to increase at midlatitudes, and it was shown that these events are caused by convergence of ionization in the east-west direction brought about by a northward electric field.

TL;DR: In this paper, the authors used coupled numerical models of the global ionospheric dynamo and of the equatorial electrojet to simulate the magnetic variations observed at four universal times on a quiet day.

TL;DR: In this article, the seasonal movements of the Sq foci suggest an explanation for the semi-annual variation in the electrojet amplitude, and the poleward movement of one focus at each equinox will cause an equinoctial enhancement of the electrojets.

TL;DR: The OGO-4 and 6 spacecraft made over 2000 traversals over the equatorial electrojet in the altitude range 400-800 km when local times were between 9 and 15 hr as discussed by the authors.

TL;DR: In this article, the dispersion of ducted whistlers is approximated by D = D 0 (f HE − Af) (fHE − f), where f is the whistler frequency, t the travel time and f HE the minimum electron gyrofrequency along the propagation path.

TL;DR: In this article, a detailed investigation of the relationship between the equatorial anomaly and the strength of the Equatorial electrojet was made using data for all of 1958 in four longitude sectors.

TL;DR: In this article, the authors studied the dynamical perturbations on the ionizations in middle altitudes at night by solving the time-dependent continuity equation involving the charge transport effects and found that the propagating (2.4) mode of the solar semi-diurnal atmospheric tide is the dominant cause of the intermediate layers at night.

TL;DR: In this article, the main features of the nonducted wave have been interpreted by ray tracing in models of the magnetosphere, and the results improve our understanding as to why very few whistlers are observed on the ground at low latitudes.

TL;DR: In this article, the effects of an eastward electric field on the ionosphere were examined and the results of the calculation were compared with observed results obtained by Evans during a magnetic storm.

TL;DR: In this article, the effect of internal atmospheric gravity waves upon columnar electron content was studied using a model consisting of plane internal gravity waves propagating in a viscous atmosphere composed of a number of isothermal layers.

TL;DR: In this paper, a self-consistent, two-dimensional, twocomponent diffusion model is presented to describe the diurnal component of thermosphere dynamics, and the magnitude of the temperature-density phase delay is discussed with respect to its dependence on the electron density distribution.

TL;DR: In this article, the nighttime atmospheric sodium layer has been measured over a period of four months at Sao Jose dos Campos (23°S, 46°W), using the laser radar technique.

TL;DR: In this article, the global evolution of foF2 at middle and low latitudes is studied for several very severe and a few moderate storms and it is concluded that storm-time ionospheric changes are of secondary nature caused as after-effects more probably by erratic neutral winds flowing from polar regions towards the Equator than by electrostatic fields developed in the magnetosphere during geomagnetic storms.

TL;DR: In this article, an elaborate photochemical model of the Earth's tropical atmosphere from 60 to 160 km has been constructed, incorporating 46 constituents, and associated chemical reactions, for an oxygen-hydrogen-nitrogen-carbon atmosphere involving neutral, electronically excited and both positive and negative ionized species.

TL;DR: In this paper, a fast and simple method was developed for the determination of whistler nose frequency (fn) and travel time at the nose (tn) when both the nose frequency and the causative spheric are not directly identifiable on whistler spectrograms.

TL;DR: In this paper, the photodetachment of electrons from major negative ions is shown to be necessary in order to account for the daytime electron concentrations observed below 70 km, and a model for the normal daytime D -region is formulated.

TL;DR: In this article, the fading of radio waves reflected from the upper D -region of the ionosphere has been studied using the spaced receiver technique and full correlation analysis, and the resulting ionospheric drift velocities are shown to provide reliable estimates of the motion of the neutral air in the reflection region.

TL;DR: In this article, the authors make clear the ducted propagation of low-latitude whistlers by making use of the simultaneous observations at several stations in Japan, i.e. Kagoshima (geomag. lat. 20°N), Sakushima (24°N) and Moshiri (34°N).