Spread F in the Midlatitude Ionosphere According to DPS-4 Ionosonde Data
The results of studying spread F obtained from the DPS-4 ionosonde data at the observatory of the Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Moscow) are presented. The methodical questions that arise during the study of a spread F phenomenon in the ionosphere are considered; the current results of terrestrial observations are compared with previously published data and the results of sounding onboard an Earth-satellite vehicle. The automated algorithm for estimation of the intensity of frequency spread F, which was developed by the authors and was successfully verified via comparison of the data of the digisonde DPS-4 and the results of manual processing, is described. The algorithm makes it possible to quantify the intensity of spread F in megahertz (the dFs parameter) and in the number of points (0, 1, 2, 3). The strongest spread (3 points) is shown to be most likely around midnight, while the weakest spread (0 points) is highly likely to occur during the daytime. The diurnal distribution of a 1–2 point spread F in the winter indicates the presence of additional maxima at 0300–0600 UT and 1400–1700 UT, which may appear due to the terminator. Despite the large volume of processed data, we can not definitively state that the appearance of spread F depends on the magnetic activity indices Kp, Dst, and AL, although the values of the dFs frequency spread interval strongly increased both at day and night during the magnetic storm of March 17–22, 2015, especially in the phase of storm recovery on March 20–22.
Unable to display preview. Download preview PDF.
- Antonov, A.M., Nepomnyashchaya, E.V., and Fatkullin, M.N., The phenomenon of spread-F in daytime midlatitude ionosphere, Geomagn. Aeron., 1987, vol. 27, no. 5, pp. 831–833.Google Scholar
- Deminov, M.G. and Nepomnyashchaya, E.V., Dependence of the midlatitude F-spread probability on solar and geomagnetic activity, Geomagn. Aeron. (Engl. Transl.), 2003, vol. 43, no. 6, pp. 711–717.Google Scholar
- Deminov, M.G., Karpachev, A.T., and Nepomnyashchaya, E.V., Relationship between seasonal variations in nighttime midlatitude spread-F and solar and geomagnetic activities, Geomagn. Aeron., 1991, vol. 31, no. 6, pp. 1102–1104.Google Scholar
- Deminov, M.G., Nepomnyashchaya, E.V., and Sitnov, Yu.S., Regularities of the midlatitude spread-F occurrence probability during sunrises and sunsets, Geomagn. Aeron. (Engl. Transl.), 2005, vol. 45, no. 4, pp. 458–465.Google Scholar
- Gershman, B.N., Kazimirovskii, E.S., Kokourov, V.D., and Chernobrovkina, N.A., Yavlenie F-rasseyaniya v ionosfere (The Phenomenon of Spread-F in the Ionosphere), Moscow: Nauka, 1984.Google Scholar
- Rodger, A.S., Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic midlatitudes, J. Atmos. Terr. Phys., vol. 46, no. 4, pp. 335–342.Google Scholar
- Rodger, A.S., Diffuse reflections of radio waves from the ionospheric F-layer (spread-F) over Argentine Islands, Antarctica, Br. Antarct. Surv. Sci. Rep., 1982, no. 106.Google Scholar
- Telegin, V.A., Panchenko, V.A., and Rozhdestvenskaya, V.I., Preliminary results of the study of spread-F according to data from DPS-4 ionosonde in Moscow, Sovrem. Probl. Distantsionnogo Zondirovaniya Zemli Kosmosa, 2014a, vol. 11, no. 1, pp. 97–106.Google Scholar
- Telegin, V.A., Panchenko, V.A., and Rozhdestvenskaya, V.I., The capabilities of the DPS-4 ionosonde for studying the phenomenon of spread-F, in Tr. 37 seminara po fizike avroral’nykh yavlenii (Proc. 37th Annual Seminar on Physics of Auroral Phenomena), Apatity, 2014b, pp. 98–103.Google Scholar