DocumentCode :
784760
Title :
Oblique ionogram features associated with off-great circle HF propagation at high and sub-auroral latitudes
Author :
Rogers, C.C. ; Warrington, E.M. ; Jones, T.B.
Author_Institution :
Leicester Univ., UK
Volume :
150
Issue :
4
fYear :
2003
Firstpage :
295
Lastpage :
300
Abstract :
Oblique ionograms received over northerly paths are often difficult to interpret, with many features not being of the form observed on the more familiar mid-latitude soundings. In particular, the ionograms contain unusual traces at frequencies close to and above the conventional or basic maximum usable frequency, i.e. above the junction frequency of the high and low angle modes. A series of experiments have been undertaken over a period of several years to investigate off-great-circle propagation mechanisms over high latitude and sub-auroral oval paths. In addition to measurements of the signal direction of arrival, oblique ionograms were also recorded over several of the paths. By these means, the characteristic ionogram signatures associated with off-great-circle propagation effects arising due to the presence of convecting patches of enhanced ionisation or sun-aligned arcs within the polar cap ionosphere, or to the presence of steep gradients to the side of the path within the mid-latitude trough region, have been identified.
Keywords :
HF radio propagation; ionisation; ionospheric electromagnetic wave propagation; enhanced ionisation convecting patches; high latitudes; mid-latitude trough region; oblique ionogram features; off-great circle HF propagation; off-great-circle propagation; polar cap ionosphere; sub-auroral latitudes; sun-aligned arcs;
fLanguage :
English
Journal_Title :
Microwaves, Antennas and Propagation, IEE Proceedings
Publisher :
iet
ISSN :
1350-2417
Type :
jour
DOI :
10.1049/ip-map:20030552
Filename :
1232598
Link To Document :
بازگشت