Lower ionosphere model for noon quiet conditions and conditions of sudden ionospheric disturbances according to the data on VLF propagation

• Published in: Geomagnetism and Aeronomy Vol. 51; no. 1; pp. 78 - 87
• Main Authors: Orlov, A. B., Uvarov, A. N.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01.02.2011; Springer Nature B.V
• Subjects: Aeronomy; Atmospheric models; Earth and Environmental Science; Earth Sciences; Geophysics; Geophysics/Geodesy; Ionosphere; International Reference Ionosphere; FIRI Model; Disturbed Condition; Lower Ionosphere; Quiet Condition
• ISSN: 0016-7932; 1555-645X; 0016-7940
• DOI: 10.1134/S0016793211010105

The parameters of a model of the lower daytime ionosphere for quiet conditions and conditions of SID within the 25–75 km height interval are estimated according to experimental SPA data (at frequencies of 11.9 and 13.6 kHz), the strength of electromagnetic fields (15–25 kHz), and the phase velocity (10.2 kHz) obtained at various long paths within the 40° S–40° N latitude band for a period of high solar activity (the Wolf number is 100). At heights of 45–75 km, the created model provides the electron concentration profile and altitude dependence of the parameter of the loss coefficient type. At heights of 25–45 km, the model gives (in the cold plasma approximation) an equivalent description of the dependence on height of the ion concentration. On the basis of six samplings of VLF data formed over two-month intervals, seasonal variations of the model parameters are estimated. Joint consideration of the data for quiet and disturbed conditions and also insertion of the effective ion “layer” with a concentration maximum at a height of 35 km is a peculiar features of the model creation method.