## 2 Observations and Method for Data Analysis
### Formosat-3/cosmic (F3/c) Electron Density Profiles Data and Methodology  
These data are used for investigating the electron density profile response to concrete wave components only in December 2008, i.e., this dataset is a subsidiary one. The details about the F3/C electron density profile observations can be found in [PERSON] and [PERSON], 2011 [56], while the validation of these data was performed by comparing them with those of incoherent scatter radars and ionosondes in [PERSON] et al., 2007 [76]. Here, we will only briefly repeat that the electron density profiles were retrieved by the advanced GPS receivers on board of the F3/C constellation system, which are composed of six identical microsatellites, by using a radio occultation (RO) inversion technique [76; 77].  
We note that the electron density data employed in the present study were downloaded quite long time ago from the website: [[http://cosmic-io.cosmic.ucar.edu/cdaac/](http://cosmic-io.cosmic.ucar.edu/cdaac/)]([http://cosmic-io.cosmic.ucar.edu/cdaac/](http://cosmic-io.cosmic.ucar.edu/cdaac/)) (accessed on 10 April 2024). These data were widely used in our previous research [26; 56; 57], which forms the background of the present study. Unfortunately, the above-mentioned website is no longer active. The electron density, similarly to our previous studies, is measured by its plasma frequency in MHz. The altitude-latitude (between 100 and 800 km height with a step of 20 km and between \(70^{\circ}\) N to \(70^{\circ}\) S with a step of \(10^{\circ}\)) structure of the ionospheric electron density tidal response will be considered in this case study. It has already been mentionedthat the neutral wind and electric field effects on the ionosphere are at variance with the geomagnetic field configuration; that is why the distribution of the ionospheric parameters is usually presented in geomagnetic latitude instead of geographic one. Therefore, the F3/C electron density data, similarly to the TEC data, were re-arrayed in terms of the coordinate system of modify latitude from \(-70^{\circ}\) to \(70^{\circ}\) at each \(10^{\circ}\), and geographic longitude from \(-180^{\circ}\) to \(180^{\circ}\) at each \(15^{\circ}\). The data were analyzed in the same way as those of SABER and TEC data.  
Similarly to the SABER data, here, also, an important problem in the electron density tidal response assessment is the determination of the reference noise level. This is due to the F3/C satellite data sampling pattern and the variability of the ionosphere, particularly near the F-region maximum at low latitudes. This problem has been investigated in detail by [PERSON] and [PERSON], 2012 [55]. The analysis revealed that all COSMIC tidal waves extracted from a given 60-day window with amplitudes larger than 0.02 MHz are accepted as statistically significant.  
Climatology (2002-2022), Seasonal and Interannual Variability of the SABER/TIMED Nonmigrating Tides in the Lower Thermosphere  
It has already been clarified in the Introduction that this study will not consider all nonmigrating tides (there are 32 of them), but only those nonmigrating tides which are largely responsible for the global longitudinal structures both in the lower thermosphere and in the ionosphere. It is certain that the strongest nonmigrating tides, which are the diurnal and semidiurnal ones, could make a large contribution to the production of longitudinal structures. Precisely such 5 (five) tides will be examined in detail in this paper; according to the above-mentioned standard nomenclature these are: DE3, DE2, DW2, SW4, and SE2. Further, the climatology of these nonmigrating tides will be considered in the MLT region. However, their seasonal and interannual variability will be shown only in the lower thermosphere (in this case it is altitude of 110 km) because, as mentioned in the Introduction, the neutral dynamics renders the lower thermosphere into the strongest driver of the ionospheric variability.