Propagation of HF Radiowaves on High-Latitude Radio Paths during the Magnetically Disturbed Period of October 24-28, 2003

摘要

The behavior of the HF signal parameters during magnetic storms and substorms has bee experi-mentally studied simultaneously on the Kiruna—Kirkenes auroral path, Kiruna—Longyearbyen polar path,and Murmansk—St. Petersburg subauroral path. The first two paths are equipped with the instruments makingit possible to measure the values of the signal-to-noise ratio, Doppler frequency shift, and elevation angle.The method of oblique sounding of the ionosphere (OSI) was used on the Murmansk—St. Petersburg path.Two substantial substorms, a moderate storm, and an intense storm occurred during the studied period. Somenew regularities have been revealed. On the Kiruna—Kirkenes and Kiruna—Longyearbyen paths, the signal-to-noise ratio increased (due to the transition from the F_2signal reflections to theE_sreflections), the elevationangle increased (due to an increase in the ionospheric F_2layer height and a decrease in the critical frequency),and the Doppler shift increased (due to the variations in ionization and the appearance of ionospheric irreg-ularities during a substorm) when the signal was reflected from the F_2layer close to the moment of the sub-storm or storm beginning T_0. It is possible to control the so-called "main effect" in the ionosphere on theMurmansk—St. Petersburg path.