Regular TEC variations in mid-latitude and polar regions

We carry out morphological spectral analysis of regular total electron content (TEC) variations, based on the data of dual-frequency GPS/GLONASS receivers located in mid-latitude and polar regions for the period from 2002 till 2015. We reveal basic harmonics, existent in TEC spectrum and determine their features. It is shown that variations with periods of 1, 1/2 ... and up to 1/5 of a day, 27-days as well as 1, 1/2 ... of a year constantly present in TEC spectrum. The amplitude and the number of clearly prominent harmonics vary according to solar activity level. It is noted that TEC variations patterns throughout the year in the mid- and high-latitude regions are similar. We also compared the dynamics of TEC variations with global electron content and F10.7 solar radio flux changes and showed that in general, all the ionospheric harmonics repeat F
_{10 7}
dynamics.