Showing papers in "Journal of Atmospheric and Solar-Terrestrial Physics in 1994"

TL;DR: In this article, a statistical analysis is made of inertio-gravity waves (IGWs) with short vertical wavelengths (4 km) and long ground-based periods (⩾ 10 h) which are dominant in the lower stratosphere in all seasons.

TL;DR: In this article, the authors reviewed the results of comparative studies on the latitudinal variations of the gravity wave activity, which were detected by additionally employing data obtained with MF radars at Adelaide (35°S, 139°E) and Saskatoon (52, 107W) and lidar observations at Haute Provence (44, 6E).

TL;DR: In this paper, an all-sky imaging system was operated at Cachoeira Paulista (22.7° S, 45.0° W, dip latitude 15.8° S), between March 1987 and October 1991, with ionospheric soundings carried out at both C. Paulista and Fortaleza.

TL;DR: In this paper, a unified discussion of the various tomographic reconstruction algorithms is presented, and the difference between the reconstruction methods arises from different choices for the basis functions which are used to represent the unknown electron density structure.

TL;DR: In this paper, the authors investigated the possibility that the quasi-two-day wave maintains its phase relation, with respect to the local solar time, from year to year, from 1980 to 1991.

TL;DR: In this article, it was shown that classic Trimpis and RORDs initiated by the same sferic usually come from measurably different directions, so the lightning-induced ionisation enhancements (LIEs) which cause them must be laterally displaced.

TL;DR: A review of periodic and quasiperiodic VLF emissions observed at ground-based stations and in the Earth's magnetosphere is presented in this paper, where emissions with periods below 10 s are divided into three main groups: periodic emissions, hisslers and pulsing hiss.

TL;DR: In this article, a comprehensive model of atmospheric M2 lunar tidal oscillations from the surface to the lower thermosphere (c. 105 km), taking account of the above-mentioned effects i.e. Earth, ocean and load tides, is presented.

TL;DR: In this article, the authors report on intercomparisons of data from ground-based instruments (Rayleigh and sodium-lidar), balloon-borne methods (datasondes and radiosondes) and rocket-borne techniques (falling spheres and ionization gauges).

TL;DR: In this paper, the large scale character of the observed quasi-two-day fluctuations in the whole ionosphere (from D - up to F -region maximum) over Europe is shown.

TL;DR: In this paper, the results of MF radar observations of mean winds and waves in the height range 78-108 km at Mawson (67°S, 63°E), Antarctica were presented.

TL;DR: In this paper, the authors studied the effects of solar activity on the ionospheric electron content (IEC) at conjugate stations in the equatorial anomaly and mid-latitude regions under moderate to high solar activity conditions.

TL;DR: In this paper, VHF radar measurements of velocities and echo power in the summer polar mesosphere have been analyzed using maximum entropy, bispectral and cross-spectral methods in order to study wave-wave interactions.

TL;DR: In this paper, the results of statistical analyses of more than 7000 rocket and radiosonde sounding from five stations between 1964 and 1990 are presented, and the main conclusion is that the stratosphere and mesosphere become cooler from 1964 to 1990.

TL;DR: In this article, the amplitude and phase modulations of the pseudo 2-day wave are analyzed over 2-4 days as a 48-hour component, and strong evidence of solar influence on the wave is found.

TL;DR: In this paper, the authors measured the vertical temperature profiles in the middle atmosphere above 11 rocket and four lidar stations in the northern hemisphere during the DYANA campaign (January-March 1990) and found that more than 50% of the temperature variance could be attributed to the quasi-stationary planetary wave No. 1 (QSW 1) modulation.

TL;DR: In this paper, the mean wind and tidal data were analyzed with a special emphasis upon solar activity and the possible influence of the equatorial quasi-biennial oscillation (QBO) on mesospheric circulation.

TL;DR: In this paper, the A3 method was used to study long-term trends in the planetary wave activity in the period range of 2-15 days in the upper middle atmosphere.

TL;DR: In this article, the seasonal and solar activity variations of night-time total electron content (TEC) enhancements and their latitudinal and longitudinal dependencies in the northern equatorial anomaly region (11 −23° geomagnetic latitude) were studied by using data from three eastern longitude stations and one western longitude station.

TL;DR: In this article, a set of tabulated functions called "Hough Mode Extensions" (HMEs), which represent numerical extensions of classical Hough modes into the viscous regime of the thermosphere, are used to least squares fit a climatological data base of tidal measurements.

TL;DR: In this article, the authors present a procedure based on weighted least squares, which may be applied to an entire recording or to suitably selected parts of it, to yield the best estimates of VX, VY, VZ and their confidence limits.

TL;DR: In this article, the vertical drift velocity of the F-region in the post-sunset period at the magnetic equatorial station Trivandrum has been studied using a HF phase path sounder.

TL;DR: In this paper, the authors present altitude profiles of turbulent parameters, such as turbulent energy dissipation rates e and turbulent diffusion coefficients K, which were derived from a total of eight successfully launched instruments at high (Andoya, 69°N) and middle (Biscarosse, 44°N).

TL;DR: In this paper, one year of northern hemisphere stratospheric temperatures at 30 and 50 mb were compared, respectively, with 20-yr (1965-1984) and 26-yr monthly means.

TL;DR: In this article, the influence of geomagnetic storms on the wind field of the mesosphere and lower thermosphere was investigated by means of ground-based observations with two MF radars, four meteor radars and two LF wind profilers in middle and high latitudes of the northern hemisphere.

TL;DR: In this article, measurements of ionospheric electron density vertical profiles, carried out at a magnetic equatorial station located at Fortaleza (4°S, 38°W; dip latitude 2°S) in Brazil, are analyzed and compared with low-latitude electron density profiles predicted by the International Reference Ionosphere (IRI) model.

TL;DR: In this article, the disturbances observed by the Japanese ionospheric observation network following the explosions of Mount Pinatubo on 15 June 1991, are presented, and the surface pressure fluctuations due to the passage of atmospheric waves were confirmed by the microbarograph chain data in Japan.

TL;DR: In this paper, a comparison of nightly means of OH∗ rotational temperatures measured at Yakutsk, Kiruna, Andoya, Biscarrosse, and El Arenosillo during the DYANA campaign reveals information about dynamics in the 86 km altitude region that includes relatively short-range temperature gradients at high latitudes associated with a stratospheric warming, and long-range oscillations with periods from about 2 to more than 30 days that can be attributed to travelling or quasi-stationary planetary waves.

TL;DR: In this paper, the wind field of the upper mesosphere and lower thermosphere region over Central Europe (52°N, 15°E) has been continually and reliably recorded by regular daily D1 radio wind measurements in the LF range (177, 225 and 270 kHz) using commercial radio transmitters.