Accession Number : ADP002730

Title :   F-Region Variability and HF (High Frequency) Propagation,


Personal Author(s) : Paul,A. K.

Report Date : AUG 1983

Pagination or Media Count : 13

Abstract : Very little is known about short term variations (gravity wave activity with periods less than two hours) in the F-region and their effects on HF-propagation, mainly for two reasons: (a) even ionograms are recorded in 15 minute intervals at most stations in the international network, only hourly values are scaled, and (b) distances between stations are much larger than the horizontal structure size corresponding to the short term temporal fluctuations. A program conducted during the winter 1980/1981 in Brighton, Colorado, with a modern digital ionosonde was aimed towards improvement of our knowledge regarding the temporal variations. Rapid sequences of ionograms were taken in irregular intervals and the analysis concentrated mainly on the maximum usable frequency MUF (3000) as a very sensitive combined indicator for variations in height and electron density. This quantity could be computed automatically with very high precision.

Descriptors :   *Ionospheric propagation, *F region, Ionosondes, Gravity waves, Ionograms, High frequency, Electron density, Horizontal orientation, Digital systems, Structural properties, Time intervals, Networks, Sizes(Dimensions), Sequences, Colorado, International

Distribution Statement : APPROVED FOR PUBLIC RELEASE