Substorm Manifestations at Radio Paths of Oblique Ionospheric Sounding in the Arctic
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Pure and Applied Geophysics
Substorm Manifestations at Radio Paths of Oblique Ionospheric Sounding in the Arctic D. V. BLAGOVESHCHENSKY1 and M. A. SERGEEVA2,3 Abstract—The impact of geomagnetic substorms on radio propagation within the high-frequency (HF) range was analyzed using oblique ionospheric sounding data. These data were obtained from the unique system of radio paths that covers the whole region of the Russian Arctic. The study focused on the effects of two substorms with a twofold difference in intensity. Variations of four radio propagation parameters were studied: the maximum and lowest observed frequencies of the F2 ionospheric layer (F2MOF and F2LOF), and the same frequencies of the sporadic Es layer (EsMOF and EsLOF). Even the weak geomagnetic substorm (AEmax * 500 nT) significantly changed the ionosphere state and, consequently, the character of radio propagation at paths. The absorption of signals was more pronounced during a more intense substorm which resulted in loss of information during the transmissions through HF channels. The variations of propagation parameters (DMOF and DLOF) depend more on the path reflection point location and on the intensity of a substorm. Two substorms with a twofold difference in intensity had similar effects on DMOF, except for (a) the more pronounced smoothing of the Main Effect and (b) the higher DEsMOF amplitude during the intense substorm. Both issues are explained by more intense particle precipitations during the more intense disturbance. Keywords: Geomagnetic substorm, ionosphere, oblique sounding, radio propagation, high-latitudes.
1. Introduction Nowadays, exploration of natural resources in the Arctic region (for instance, in Canada, the USA, Norway, Russia) is one of the topical issues. A
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Saint-Petersburg State University of Aerospace Instrumentation, 67, Bolshaya Morskaya, Saint-Petersburg 190000, Russia. 2 SCiESMEX, LANCE, Instituto de Geofisica, Unidad Michoacan, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, Morelia, Michoacan C.P. 58089, Mexico. E-mail: [email protected] 3 CONACYT, Instituto de Geofisica, Unidad Michoacan, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, Morelia, Michoacan C.P. 58089, Mexico.
special focus is on the Arctic shelf, where oil and gas recovery is expected on a large scale. This implies the utilization of manpower resources under severe environmental conditions. People work in mining parties and production platforms, keep possible ship journeys, aviation and helicopter flights in the Arctic region. All these activities require reliable radio communication for all production sectors and users in the region. Satellite communications are reliable, but rather expensive. Another option is high-frequency (HF) communications, whose cost is relatively low. At the same time, it is susceptible to geomagnetic disturbances that are known to be most prominent at high latitudes (Hunsucker and Hargreaves 2003). There are numerous fruitful attempts to improve the q
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