Results 221 to 230 of about 792,234 (268)

Classification of spread-F ionograms

Journal of Atmospheric and Terrestrial Physics, 1962
Abstract Scaling of original ionograms obtained in the polar regions has lead to a classification scheme for spread-F ionograms. Defined are three types of frequency spreading (spreadish-F, furcated-F and spurred-F) and one type of range spreading. Each type is subdivided into species.
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The nocturnal and seasonal variations of spread-F

Journal of Atmospheric and Terrestrial Physics, 1963
Abstract The nocturnal variations of spread- F at Waltair using data over a period of 22 months (March, 1960–December, 1961) are studied and discussed in comparison with the variations at other equatorial stations. The seasonal characteristics of spread- F are studied separately for magnetically quiet and disturbed days, using data at four ...
B.V. Krishnamurthy, B.Ramachandra Rao
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A study of midlatitude spread-F

Journal of Atmospheric and Terrestrial Physics, 1977
Abstract Results of a study of the occurrence of spread-F at Christchurch (43.6°S, 172.8°E; invariant latitude Λ = 49.0°S) over the period June 1965-December 1974 are presented. There is a significant positive correlation between the occurrence of spread-F in the post-midnight period and Kp, the occurrence of spread-F lagging behind Kp by 1 to 2 days.
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Spread-F and the Latitude Variation of Occurrence of Whistlers

Nature, 1961
RECENT work of whistling atmospherics has suggested that the incidence of the phenomenon is dependent on latitude. Crouchley1, using data from Australian and Japanese stations, demonstrated that whistler activity reaches a maximum at about 45°geomagnetic latitude, while the Stanford group 2 report a maximum of occurrence at 50°geomagnetic latitude.
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Artificial control of equatorial spread-F

Journal of Atmospheric and Terrestrial Physics, 1978
Abstract We have studied the influence of a large amplitude electric field oscillating near the upper hybrid frequency on the dispersion characteristics of low frequency Rayleigh-Taylor modes and collisional drift modes. Since these modes have been proposed as principal constituents of spread- F , we investigate the conditions for the parametric ...
S Bujarbarua, A Sen
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Control of equatorial spread-F by the F-layer height

Journal of Atmospheric and Terrestrial Physics, 1966
Abstract The dependence of equatorial spread-F occurrence on the height of the layer is examined in detail in the case of two equatorial stations viz. Kodaikanal and Huancayo, lying close to the magnetic equator. The percentage of occurrence associated with different heights is found to vary with time, season and longitude.
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On a model of artificial F-spread in the ionosphere

Radiophysics and Quantum Electronics, 1996
The results of a complex experiment on the synchronous observation of geostationary-satellite signals and of reflected HF signals of the vertical-sounding station in the course of ionosphere modification by powerful short waves are analyzed using the method of refractive scattering of radio waves.
V. A. Alimov, A. V. Rakhlin
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Spread-F at Temperate and High Latitudes

IETE Journal of Research, 1966
ABSTRACTSpread-F at temperate and high latitudes has been analysed to study its variation with season, geomagnetic activity, sunspot activity and h'F. It is observed that at low temperate latitudes there is no correlation with geomagnetic activity. At high temperate latitudes spread-F is positively correlated with geomagnetic activity in winter and ...
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Spread-F and ionization anomaly belt

Journal of Atmospheric and Terrestrial Physics, 1989
The present investigation attempts to bring out the dynamics of the F-region at magnetic equatorial and low latitudes in the American zone. Data are examined for two sets of nights, one with strong range-type spread at Huancayo another with complete absence of spread-F.
S. Alex, P.V. Koparkar, R.G. Rastogi
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Spread-F and the parameters of the F-layer of the ionosphere-II. Spread-F and F-layer height

1962
An analysis has been made of spread-F data obtained from I.G.Y. f{hook}-plots for several ionosonde stations grouped about longitude 75°W to establish whether there is any connexion between the incidence of the frequency-spreading component of spread-F and the height of the F2-layer.
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