The method earlier used for the foF2 long-term trends analysis is applied to reveal hmF2 long-term trends at 27 ionosonde stations in the European and Asian longitudinal sectors. Observed M(3000)F2 data for the last 3 solar cycles are used to derive hmF2 trends. The majority of the studied stations show significant hmF2 linear trends with a confidence level of at least 95% for the period after ...

In spite of being interrupted several times in its long history operation since 1950, the routine observation ionosphere with various ionosondes installed at Chung-Li station Taiwan has been achieved successively for more than seven decades. this article, system characteristics latest ionosonde and algorithm developed by National Central University ionogram scaling true height analysis, which s...

In this study, we investigate the negative ionospheric response over European sector during two storms that took place on 8 September 2017, primarily, by exploiting observations ten locations. The spatial and temporal variations of TEC, foF2 hmF2 characteristics are examined with aim to explain physical mechanisms underlying strong response. We detected very sharp electron density (in terms TEC...