Results 261 to 270 of about 781,821 (303)

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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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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Equatorial Spread-F and Magnetic Activity

Nature, 1958
IT is well known that the ionospheric spread-F condition is extremely common at night in equatorial regions. At Ibadan, Nigeria (latitude 7½°N.), this has been especially so during the past 2½ years of high sunspot activity. It is believed that the same irregularities which produce the wide spread of scattered echoes from the F-region are also ...
A. J. LYON, N. J. SKINNER, R. W. WRIGHT
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Quantifying spread F by digital ionosondes

Advances in Space Research, 2003
The width of frequency-spreading (Δff) on ionograms was shown (Wright, et al., 1977, by comparison with OGO-6 Satellite observations) to be proportional to ΔNN near and above the F-region peak. Thus, even classical analog ionograms using logarithmic frequency scales were direct reading for this important parameter, although little use has been made of ...
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Plasma density discontinuity and spread F

Journal of Atmospheric and Terrestrial Physics, 1984
It is shown that the generation of the equatorial spread F irregularity in the post-sunset period need not he always at the base of the F region. The irregularities are generated at the E region, provided there existed a retardation type E2 layer or a uniform blanketing sporadic E layer before the sunset.
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The aspect sensitivity of spread-F irregularities

Journal of Atmospheric and Terrestrial Physics, 1971
Abstract A high latitude oblique incidence echo, previously shown to be produced by irregularities strongly aligned along the magnetic field, is found to occur whenever vertical incidence spread- F is recorded from the same volume of the F -layer.
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Equatorial spread-F and solar activity

Journal of Atmospheric and Terrestrial Physics, 1964
Abstract The effect of solar activity on equatorial spread- F has been studied using the published tables of f 0 F 2 from six Afro-Asian stations. The strong negative correlation between equatorial spread- F and magnetic activity observed during sunspot maximum is no longer significant during low sunspot years.
S. Rangaswamy, K.B. Kapasi
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On the region of mid-latitude spread-F

Acta Geodaetica et Geophysica Hungarica, 2002
Mid latitude spread-F has extensively studied recently as compared to the earlier periods. In the course of these investigations two concepts have appeared in the literature concerning the origin of the mid-latitude spread-F. The first concept based on radar measurements attributes the development of spread-F to plasma instabilities (Fukao et al. 1988),
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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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Lunar variations of spread-F

Journal of Atmospheric and Terrestrial Physics, 1962
B.V. Krishnamurthy, B.Ramachandra Rao
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