Winter Anomaly in the Critical Frequency of the E-Layer in the Nighttime Polar Cap
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With the medians of the E-layer critical frequency foE measured at Resolute Bay and Casey ionospheric stations located in the polar caps of the Northern and Southern Hemispheres, it is found that these medians are higher at the nighttime hours (2100–0300 LT) in the local winter than in local summer. For Resolute Bay station, which is located above the Arctic Circle, the latter means that the foE median is higher at polar night than at polar day. Thus, the effect of a winter anomaly in the foE median in the nighttime polar cap is detected. The amplitude of that anomaly (the ratio of the local winter foE values to local summer values) could reach 15–20% and 10–15% for Resolute Bay and Casey stations, respectively. It is assumed that the winter anomaly in the foE median in the nighttime polar cap is caused by the winter–summer asymmetry in the accelerated electron energy fluxes precipitating into this region.
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- Brunelly, B.E. and Namgaladze, A.A., Fizika ionosfery (Ionospheric Physics), Moscow: Nauka, 1988.Google Scholar
- Hunsucker, R.D. and Hargreaves, J.K., The High-Latitude Ionosphere and Its Effects on Radio Propagation, Cambridge: Cambridge University Press, 2003.Google Scholar
- Newell, P.T., Sotirelis, T., and Wing, S., Seasonal variations in diffuse, monoenergetic, and broadband aurora, J. Geophys. Res., 2010, vol. 115, A03216. doi 10.1029/2009JA014805Google Scholar
- Perry, G.W., Dahlgren, H., Nicolls, M.J., and Zettergren, M., St.-Maurice, J.-P., Semeter, J.L., Sundberg, T., Hosokawa, K., Shiokawa, K., and Chen, S., Spatiotemporally resolved electrodynamic properties of a Sun-aligned arc over Resolute Bay, J. Geophys. Res.: Space, 2015, vol. 120, pp. 9977–9987. doi 10.1002/2015JA021790CrossRefGoogle Scholar
- Ramachandran, K.M. and Tsokos, C.P., Mathematical Statistics with Applications, Oxford: Elsevier, 2009.Google Scholar
- Schunk, R.W. and Nagy, A.E., Ionospheres: Physics, Plasma Physics, and Chemistry, Cambridge: Cambridge University Press, 2009.Google Scholar
- Titheridge, J.E., Re-modeling the ionospheric E region, Kleinheubacher Ber., 1996, vol. 39, pp. 687–696.Google Scholar
- Zou, Y., Nishimura, Y., Lyons, L.R., Donovan, E.F., Shiokawa, K., Ruohoniemi, J.M., McWilliams, K.A., and Nishitani, N., Polar cap precursor of nightside auroral oval intensifications using polar cap arcs, J. Geophys. Res.: Space, 2015, vol. 120, pp. 10698–10711. doi 10.1002/2015JA021816CrossRefGoogle Scholar