Showing papers in "Journal of Atmospheric and Solar-Terrestrial Physics in 1989"

TL;DR: In this article, it was shown that sporadic-E is most likely due to a vertical shear in the horizontal east-west wind and this theory accounts for the detailed observations of the wind and electron density profiles.

TL;DR: In this paper, the authors presented monthly simulations of the solar semidiurnal tide in the 80-100 km height regime using the COSPAR international reference atmosphere and the gravity wave saturation climatology.

TL;DR: In this paper, the radars utilized are meteor (2), medium-frequency (2) and new low frequency (1) systems: analysis techniques have been exhaustively studied internally and comparatively and are not thought to affect the results.

TL;DR: In this paper, the existence of an 8-hour terdiurnal wave was investigated using French meteor radars at Garchy (Lat. 47°N) and Montpazier (lat. 44°N).

TL;DR: In this paper, some key observational evidence, that throws light on current questions regarding the Antarctic ozone hole, is discussed, together with dynamical theory and high-resolution numerical modelling results.

TL;DR: In this paper, the high-latitude structure of the mean winds and tides is described using climatologies prepared from radar data during the Atmospheric Tides Middle Atmosphere Program, and the monthly evolution of the amplitude and phase of the tides is discussed.

TL;DR: In this paper, the authors used radar wind measurements made at Adelaide (35°S, 138°E) and Kyoto(35°N, 136°E), Australia to construct climatologies of solar tidal wind motions in the 80-185 km region.

TL;DR: In this paper, the main phase of the F-region storm which usually begins a few hours after the onset of a significant increase of geomagnetic activity has been studied, and it is shown that the energy sources are the precipitation of ring current ions, particularly O+, and the penetration of the cross-tail magnetospheric electric field to mid-latitudes in the first few hours of the storm.

TL;DR: In this paper, a review of recent progress in identifying the physical mechanisms governing the propagation of atmospheric tides and in performing numerical simulations of the phenomenon, is reviewed. Specific attention is given to gravity-wave/tidal interactions, non-linear interactions between tides, numerical simulation of the diurnal tide, and month by month simulations of semidiurnal tide.

TL;DR: In this paper, when the data were separated according to the east or west phase of the Quasi-Biennial-Oscillation (Q.B.O.) in the equatorial stratosphere, the following connection was found: when the Q.b.o. is in its west phase, the global total ozone is positively correlated with the solar cycle; the opposite holds for the east phase of Q. b.O.

TL;DR: In this paper, the authors used the MSIS86 model to relate the heights hmF2 to values of atmospheric pressure, finding that the F 2-peak lies at nearly the same pressure level at any given local time, over a wide range of geophysical conditions.

TL;DR: In this article, the effects of momentum deposition due to solar diurnal and semi-diurnal tidal waves on the zonal mean circulation in the mesosphere and lower thermosphere for a solstice condition are discussed.

TL;DR: In this paper, the status of knowledge concerning energetic electron precipitation at the South Atlantic Magnetic Anomaly (SAMA) has been reviewed and a synopsis of results achieved in the last two decades, in relation to various physical mechanisms responsible for precipitating energetic electrons, are also presented.

TL;DR: In this article, the International Reference Ionosphere (IRI-86) was compared with the Millstone Hill incoherent scatter (IS) observations of electron density (Ne, electron temperature (Te) and ion temperature (Ti) for both noon and midnight, for summer, equinox and winter, at both solar maximum (1979-1980) and solar minimum (1985-1986).

TL;DR: In this paper, the EISCAT incoherent scatter radar was used to show that the action of a gravity wave, generated by auroral Joule heating, could be the mechanism responsible for the simultaneous occurrence of sporadic-E layers and sudden neutral sodium layers.

TL;DR: EISCAT has made regular measurements of plasma velocity at heights between 101 and 133 km in the E -region and at 279 km in F -region as part of the Common Programme CP1 Correcting for the effect of the electric field as determined by EISCAT, it is possible to estimate the neutral wind velocity in the e -region for a number of days in the period 1985-1987 when magnetic conditions were relatively quiet.

TL;DR: In this article, a review of recent progress in the study of tides in the middle atmosphere is reviewed, with special emphasis placed on radar observations at high latitudes, as well as data analysis methods used in the calculation of tidal structures.

TL;DR: In this paper, the magnetic polarization and spectral properties of four large Q-bursts are examined in detail using a new analysis technique, where the theoretical polarization properties of the central and side multiplets of the Schumann resonances are used to define a local orthogonal coordinate system in the measurement frame in which these components may be separated.

TL;DR: In this paper, a procedure for fitting incoherent scatter radar data from non-thermal F-region ionospheric plasma, using theoretical spectra previously predicted, is presented.

TL;DR: In this article, the IRI top-side model is reviewed and the electron density profile of the middle and lower ionosphere is discussed, as well as Rawer's procedure for combining the topside, middle and upper ionospheric profiles into one analytic profile is reviewed.

TL;DR: In this article, a correloperiodogram analysis to day and night-time radio wave absorption values for five LF radio paths (164, 155, 185, 218 and 272 kHz) in central and southern Europe during the interval 1 June 1979-30 June 1980, fluctuations with the following quasi-periods were found: 2.3-3.2, 4-6 and 10.5-12 days.

TL;DR: In this article, the authors investigated the dynamics of the F-region at magnetic equatorial and low latitudes in the American zone and found that a prominent bulge was observed within and below a latitude 10°N in the evening hours of the spread-F nights.

TL;DR: In this paper, the inter-annual variation in diurnal and semi-diurnal atmospheric tides between 85 and 95 km has been studied for various years between 1978 and 1988.

TL;DR: A quasi 2-day oscillation has been observed in the meteor winds at Durham since 1970 as mentioned in this paper, with amplitude of 10 m s −1 and standing wave or evanescent (λ z > 150 km ) behavior with height.

TL;DR: In this paper, two distinct approaches to the study of non-migrating tides have been proposed, based on mechanistic models that consider heating due to non-uniform global distribution of water vapour or heating only over lands, solves the primitive equations.

TL;DR: The wave-wave interaction theory has been used successfully in describing one class of weakly non-linear wave phenomena as mentioned in this paper, and it has been found that the non-resonant interaction of a gravity wave with two vortical modes can proceed at a reasonably rapid rate.

TL;DR: In this paper, it has been found that gravity waves can be generated by a total solar eclipse but their detection at ionospheric heights is critically dependent on the location of the observing station in relation to the eclipse path geometry.

TL;DR: In this paper, the authors examined the consistency of the motion spectrum with the saturated spectrum of gravity waves proposed by Smith S A, Fritts D C and Van Zandt TE, and found that saturation processes do indeed act to control spectral amplitudes at large wavenumbers.

TL;DR: In this paper, a simplified middle atmosphere general circulation model is used to investigate the nonlinear behavior of the thermal diurnal tidal waves, and the numerical results show that the growth of the diurnal tide due to the density stratification is effectively suppressed and a relatively constant amplitude distribution with height is realized by the convective adjustment in the lower thermosphere.