Results 11 to 20 of about 792,786 (268)
Seasonal variations of equatorial spread-F [PDF]
Annales Geophysicae, 1994 The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N) has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT ...
K. S. V. Subbarao, B. V. Krishna Murthy
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Spread F – an old equatorial aeronomy problem finally resolved? [PDF]
Annales Geophysicae, 2009 One of the oldest scientific topics in Equatorial Aeronomy is related to Spread-F. It includes all our efforts to understand the physical mechanisms responsible for the existence of ionospheric F-region irregularities, the spread of the traces in a ...
R. F. Woodman
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Automatic Spread-F Detection Using Deep Learning
Radio Science, 2021 Spread-F (SF) is a feature that can be visually observed on ionograms when the ionosonde signals are significantly impacted by plasma irregularities in the ionosphere. Depending on the scale of the plasma irregularities, radio waves of different frequencies are impacted differently when the signals pass through the ionosphere.
Christopher Luwanga +3 more
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Overview and summary of the Spread F Experiment (SpreadFEx) [PDF]
Annales Geophysicae, 2009 We provide here an overview of, and a summary of results arising from, an extensive experimental campaign (the Spread F Experiment, or SpreadFEx) performed from September to November 2005, with primary measurements in Brazil.
D. C. Fritts +29 more
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HF radar observations of equatorial spread-F over West Africa [PDF]
Annales Geophysicae, 1996 New experimental data depicting equatorial spread-F were taken during an HF radar sounding campaign in Korhogo (Ivory Coast, 9°24N, 5°37W, dip 4°S). Range-time-intensity maps of the radar echoes have been analyzed to identify the signatures of density
J.-F. Cécile, P. Vila, E. Blanc
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Statistical analysis of low-latitude spread F observed over Puer, China, during 2015–2016
Earth, Planets and Space, 2019 Statistical analysis of spread F (SF), recorded at Puer (PUR, 22.7° N, 101.05° E, Dip Latitude 12.9° N) during 2015–2016, was carried out to reveal its characteristics at the northern equatorial ionization anomaly.
Ting Lan +5 more
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Morphology of quantified ionospheric range spread-F over a wide range of midlatitudes in the Australian longitudinal sector [PDF]
Annales Geophysicae, 2007 Ionograms from a standard vertical-incidence ionosonde chain (nine stations), obtained over a wide range of southern latitudes (in geom.lat. range: 23°–52° S), were digitally scanned at 5-min intervals at nighttime (18:00–06:00 LT)
L. A. Hajkowicz
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Geophysical Research Letters, 1976 A numerical simulation of the non‐linear evolution of the collisional Rayleigh‐Taylor instability using a set of equations appropriate for the equatorial F region ionosphere has been performed. Our results show that the irregularities produced by the instability grow on the bottomside of the F region peak, as predicted by linear theory, and then the ...
Anthony J. Scannapieco +1 more
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Travel distance, frequency of return, and the spread of disease
Scientific Reports, 2023 Human mobility is a key driver of infectious disease spread. Recent literature has uncovered a clear pattern underlying the complexity of human mobility in cities: $$r \cdot f$$ r · f , the product of distance traveled r and frequency of return f per ...
Cate Heine +4 more
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Generation of large-scale equatorial F-region plasma depletions during lowrange spread-F season [PDF]
Annales Geophysicae, 2004 All-sky imaging observations of the F-region OI 630nm nightglow emission allow us to visualize large-scale equatorial plasma depletions, generally known as trans-equatorial plasma bubbles. Strong range type spread-F is the radio signature of these
Y. Sahai +6 more
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