Effect of the solar eclipse of 22 July 1990 at mid-latitude path of HF propagation

Autor: V. V. Shumaev, V. E. Nosov, I.G. Brinko, N.V. Ryabova, V.P. Uryadov, V.A. Ivanova, N. S. Mozerov
Rok vydání: 1998
Předmět:
Zdroj: Journal of Atmospheric and Solar-Terrestrial Physics. 60:1013-1016
ISSN: 1364-6826
DOI: 10.1016/s1364-6826(98)00043-1
Popis: Observational results obtained during the solar eclipse of 22 July 1990 using the oblique sounding method for a mid-latitude, Irkutsk to Nizhny Novgorod path are presented. A chirp sounder with high time delay and frequency resolution was used in the measurements. The electron density profile for the mid-point of the path was restored using the reduction method. It is shown that, during the solar eclipse with maximum obscuration ∼70%, the electron density in the F-region decreased by 6–8% compared with control day values. Travelling ionospheric disturbances caused by the eclipse-generated acoustic gravity waves were detected. Strong variations in the difference group delays (Δτ) between the high-angle and low-angle rays with a period ∼40 minutes associated with the start and end of the eclipse, were found. The vertical component of the disturbance speed determined from the time delay oscillation, Δτ, relative to the eclipse start for the ozone layer (near an altitude of 45 km) of the sub-ionospheric point for the 1F2 mode reflection reaches a value ∼230 m\s.
Databáze: OpenAIRE