Quasiperiodic fluctuations of electron concentration in ionospheric F2 layer: seasonal and diurnal dependences

Barabash V.V.1, Chernogor L.F.2
  1. Institute of Ionosphere, Ukrain
  2. V.N. Karazin Kharkiv National University, Ukrain

Regular and quasiperiodic seasonal and diurnal variations of electron
concentration, N, in ionospheric F2- layer during solar activity
increase (2011) are analyzed. Short-time Fourier transform, adaptive Fourier
transform and wavelet transform were applied to the system spectral analysis.
During all seasons in the ionospheric F2- layer, oscillation with the period of
  140 ÷ 200 min, ∆Na ≈ (0.2 ÷2)·1011 м−3, relative amplitude ∆Na /N ≈ 0.1 ÷ 0.2. prevailed.
The duration of this oscillation changed from 5 ÷ 7 to 24 h, depending on
a season. The fluctuation amplitude with other periods was noticeably less.