Short term variabilities of ionospheric electron content (IEC) and peak electron density (NP) during solar cycles 20 and 21 for a low latitude station |
| |
| Institution: | 1. Department of Physics S N College, Quilon - 691 001, India;2. Department of Physics University of Kerala Kariavattom, Trivandrum-695 581, India;3. Department of Applied and Computational Mathematics University of Sheffield, Sheffield S10 2TN, England;4. National MST Radar Facility ISRO, PO Box 123, Tirupati-517 502, India;1. Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Canada;2. Department of Anesthesiology, Perioperative Medicine, and Pain Management, College of Medicine, University of Saskatchewan, Saskatoon, Canada;3. Department of Community Health and Epidemiology, CRSU, College of Medicine, University of Saskatchewan, Saskatoon, Canada;1. Saint-Petersburg State University of Aerospace Instrumentation, 67, Bolshaya Morskaya Street, Saint-Petersburg 190000, Russia;2. Institute for Physics, Southern Federal University, Stachki, 194, Rostov-on-Don 344090, Russia;3. Physical Department, Southern Federal University, Sorge, 5, Rostov-on-Don 344090, Russia;4. Arctic and Antarctic Research Institute, 38 Bering Street, Saint-Petersburg 199397, Russia;1. Radiophysical Research Institute Nizhny Novgorod State University, Nizhny Novgorod 603950, Russia;2. Kazan Federal University, Kazan 420000, Russia;3. Southern Federal University, Rostov-on-Don 344006, Russia;4. Mari State University, Yoshkar-Ola 424000, Russia;5. SITCOM LLC, Yoshkar-Ola 424031, Russia;1. Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation (IZMIRAN), Kaluzhskoe shosse, 4, 108840 Moscow, Russia;2. West Department of IZMIRAN, Prospekt Pobedy, 41, 236017 Kaliningrad, Russia |
| |
| Abstract: | Hourly values of IEC and of f0F2 (critical frequency) for a low latitude station, Hawaii (21.2°N, 157.7°W), during the solar maxima (1969 and 1981) and minima (1965 and 1985) years of two consecutive solar cycles, 20 and 21, are used to study the day to day variabilities of the ionospheric parameters IEC and NP. It is found that there is good correspondence in the day to day variations of IEC and NP from one solar cycle to the other for both solar maximum and minimum years in the two solar cycles. Depending on solar phase and season, while the mean daytime IEC and NP variations range from about 20% to 35%, the mean night time values vary from about 25% to 60%. The mean daytime variations in NP for the solar minimum phase are remarkably higher in all the three seasons compared to the solar maximum phase. However, no such increase is observed in the mean daytime IEC variations, indicating the highly variable nature of the daytime ionospheric F region compared to the topside during solar minimum for this low latitude station. The winter night time IEC also seems to be a relatively stable parameter during the solar minimum. The short term day to day variabilities of the day time peak values of IEC and NP (ie IECmax and NPmax) are not closely associated with the variations in F10.7 solar flux. Contrary to the common expectation, the variabilities in both the parameters, particularly in NPmax, are somewhat reduced during the solar maximum (when the variability in F10.7 solar flux is much higher compared to the solar minimum) which is more evident in the stronger 21 solar cycle. A larger number of significant components are seen in the spectra of the percentage variation of both IECmax and NPmax during both solar phases of the two solar cycles compared to the corresponding F10.7 solar flux spectra. The number of additional components for both the parameters with periods less than 15 days are more for the low solar activity years than for the solar maximum years. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
