Some initial results on mid-latitude spread-F irregularities using a directional ionosonde

Bowman G.G. and Dunne G.S. (1981) Some initial results on mid-latitude spread-F irregularities using a directional ionosonde. Journal of Atmospheric and Terrestrial Physics, 43 12: 1295-1307. doi:10.1016/0021-9169(81)90155-0


Author Bowman G.G.
Dunne G.S.
Title Some initial results on mid-latitude spread-F irregularities using a directional ionosonde
Journal name Journal of Atmospheric and Terrestrial Physics
ISSN 0021-9169
Publication date 1981
Sub-type Article (original research)
DOI 10.1016/0021-9169(81)90155-0
Volume 43
Issue 12
Start page 1295
End page 1307
Total pages 13
Subject 1902 Film, Television and Digital Media
1908 Geophysics
Abstract Specific phase delays imposed on returning ionospheric signals received at 8 antennas in one antenna arm (500 m long) are effective in producing an interference pattern (which is displaced for off-vertical angles) on what would otherwise be a standard ionogram. Recordings from 2 antenna arms at right angles allow the calculations of zenith angles and azimuths-of-arrival for returning ionospheric signals. The system is therefore a directional ionosonde. The records show that ionospheric spread-F signals arrive predominantly from directions in the northwest quadrant consistent with earlier experimental results from Brisbane. Also, the records suggest that at these times of spread-F occurrence it is not unusual to find 'tongues of ionization' which extend some tens of kilometres below the normal level of the F2-layer. These observations are consistent with earlier reports of the existence of almost-vertical ionospheric contours of equal-ionization density. For one particular event which was analysed in detail an enhanced maximum electron-density of the F2-layer was found at the position of the 'tongue'. The occurrence of isolated patches of sporadic E with associated spreading of the Es trace (spread-Es) at the times of occurrence of 18 'tongue' events has been found to be statistically significant. It is suggested that a knowledge of the existence of these tongues at the time of occurrence of mid-latitude spread-F may give a new lead in the quest to explain how and why spread-F irregularities are formed.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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Created: Tue, 12 Jul 2016, 02:30:02 EST by System User