The Influence of the 27-Day Variation of the Upper Atmosphere Neutral-Particle Density on Ionospheric Spread-F Occurrence.
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- Bowman G. G.
- Physics Department, The University of Queensland
Bibliographic Information
- Other Title
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- Influence of the 27-Day Variation of th
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Abstract
Days of maximum 10.7 cm solar flux associated with solar rotations have been used as controls to investigate, using superposed-epoch methods, spread-F occurrence levels over a range of latitudes from sub-auroral regions to equatorial-anomaly crest regions. For all latitude regions, 27-day periodicities, and other periodicities of lesser significance, were recorded in the spread-F plots, with minima in the oscillations located near the central positions. For these oscillations spread-F occurrence levels changed by 5 percent in sub-auroral regions, about 15 percent in mid-latitude regions and 10 percent in low-latitude regions. It can be seen that, as the sun rotates, solar-activity changes have a significant influence on spread-F occurrence. With some complications, generally the spread-F minima were delayed after the solar-flux maxima by a few days. These and other experimental results suggest an explanation in terms of an hypothesis which considers the so-called 27-day variation of the upper-atmosphere neutral-particle density (neutral density) associated with the solar-rotations. The proposal is that it is the control by the neutral density of the medium-scale travelling ionosphere disturbance wave amplitudes which determines whether or not spread-F is observed on ionograms.
Journal
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- Journal of geomagnetism and geoelectricity
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Journal of geomagnetism and geoelectricity 48 (8), 1043-1057, 1996
Society of Geomagnetism and Earth, Planetary and Space Sciences
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Details 詳細情報について
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- CRID
- 1390001206510866048
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- NII Article ID
- 130003559443
- 10002202129
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- NII Book ID
- AA00698879
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- ISSN
- 21855765
- 00221392
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- NDL BIB ID
- 4079936
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed