A study of ionospheric data recorded at Slough/Chilton, UK, from 1935 to 2012, has revealed longterm changes in the relative strength of the annual and semiannual variability in the ionospheric F2 layer critical frequencies. Comparing these results with data from the southern hemisphere station at Stanley in the Falkland Islands between 1945 and 2012 reveals a trend that appears to be anti-corr...

This study is the first attempt to examine the quiet-condition variations in scale height (Hm) near the F2layer peak in the equatorial ionosphere. The data periods of Hm derived from the Jicamarca ionograms are JanuaryDecember 1996 and April 1999–March 2000. The results show that the greatest and smallest Hm values are generally at 11:00–12:00 LT and 04:00–05:00 LT, respectively. Additionally, ...

We examine systematic differences between topside electron density measurements and different model formulations including α-Chapman, NeQuick, an improved NeQuick (NeQuick-corr) formulation, recently proposed. The global data set used, was extracted from Radio Occultation (RO) profiles on board Low-Earth Orbit satellites the COSMIC/FORMOSAT-3 (Constellation Observing System for Meteorology, Ion...

A method is proposed for reconstructing the electron density profiles N(h) of IRI model from ionograms topside satellite sounding ionosphere. An feature presence traces signal reflection Earth's surface. The profile reconstruction carried out in two stages. At first stage, –profile calculated lower boundary ionosphere to height (total profile) by presented this paper using ionogram. In case, mo...

The fact is noted that sufficiently high power density HF radio waves incident on the bottom side ionosphere will produce optical emissions. It was previously suggested that the mechanism for such excitation will switch from thermal electron collision excitation to supra-thermal electron collision excitation, as the ionospheric plasma density at the reflection height switches from much below 5 ...

On the 28 October 2021, a total of thirteen solar flares occurred. Of these, there were two M- and one X-class while rest fell within C-class category. The first second M-class peaked at 0740 UT 1028 UT, respectively, X1.0 class reached peak 1535 UT. While it is known that strong cause absorption frequencies in high frequency (HF) range, F2 layer was consistently present on 2021 as shown by cri...

The rapid displacement of the ocean floor during large earthquakes or volcanic eruptions causes propagation tsunami waves on surface ocean, and consequently internal gravity (IGWs) in atmosphere. IGWs pierce through troposphere into ionospheric layer. In addition to transferring energy ionosphere, they cause significant variations parameters, so have considerable effects radio this dispersive m...