## 8 Discussion  
The temporal evolution of Ne disturbances detected by Swarm satellites is significantly correlated with the change in the persisting seismic activity in the Papua New Guinea region and in the other regions. The disturbances in Ne measured by Swarm are observed in close proximity to the earthquake series in all examples, whereas the highest values of solar radio flux are less often reflected in Ne variations. It can be observed that the largest peaks of the Swarm Ne PSD at a 300 km wavelength occur near critical seismic activity, like the earthquake series, the first earthquake after relaxation, a larger earthquake amongst some number of smaller earthquakes, or the largest earthquakes in the region. The lowest Swarm Ne PSDs coincide typically with the relaxation time or with moderate seismic activity. Figure 15: The same as in Figure 13, but for the daytime in the spring of 2016. Subfigure titles (a–c) refer directly to individual Swarm satellites. The observation of a three-month winter period in Papua New Guinea reveals different Swarm Ne disturbances, which have specific spectral patterns during different moments of continuous tectonic activity. In other words, specific spectral patterns can be found not only at the time of the largest earthquakes. The STFT analysis and the spectrograms indicate that Swarm Ne disturbances at wavelengths shorter than 300 km repeat for sudden seismic events, whereas longer-term processes that are related to seismic activity rather affect longer wavelengths. Several similar spectral representations of disturbed signals in residual Ne data are found several times, including two similar disturbances that are observed by the same satellite on different days or potentially the same disturbance observed by two satellites in consecutive passes over the region. The variation in ionospheric Ne at the Swarm altitudes is quite dynamic, and it is hard to assign every disturbed signal detected onboard Swarm to individual earthquakes. However, long-term persisting Ne changes at higher frequencies are well correlated with persistent and composite seismic activity. Therefore, longer series of Ne signal variations at 200-400 km wavelengths could be even more applicable than three-month samples in the analysis of long-term LAIC. The 10-day moving average of Swarm Ne PSDs indicates the largest long-lasting responses detected by Swarm, which almost always correspond to seismic activity increases and in many cases take place a few days before the strong earthquakes or earthquake series. The external sources of Ne disturbances, like the critical Sun activity or geomagnetic storms, can be mixed with seismically triggered internal ones in LEO satellite signals. However, the Ne disturbances are less correlated with ap and Dst indices than with earthquakes, and although there are some places where single Ne disturbances coincide best with ap/Dst variations, the groups of Ne disturbances and, in particular, their moving average fit much more to the seismic records in terms of time. Nevertheless, in future work, specific Ne disturbances that are suspected to have a geomagnetic origin, such as the discussed large Swarm B Ne peaks, could be further analyzed with respect to different geomagnetic conditions. The solar radio flux in the analyzed time series appears to be more correlated with the earthquake series than with Swarm disturbances. It is surprising, but in every Figure out of Figures 7-15, the increased parameter F10.7 coincides at most one time with a high Swarm Ne PSD at a 300 km wavelength, but often twice with increased seismic activity. The Swarm Ne PSD is also correlated with the seismic activity increases more than one time in almost every figure out of Figures 7-15, and many of these coincidences are at a time of low F10.7. This proves that both phenomena, i.e., solar activity and the earthquakes affect Swarm Ne, but the sources work separately, coincide only from time to time, and produce different Ne irregularities. The additional finding refers to the daytime Swarm signals.