Sub-auroral polarisation streams (SAPSs) are very fast plasma flows that occur at mid-latitudes, which can affect the atmosphere. In this paper, we use four ground-based radars to obtain a wide coverage of SAPSs that occurred over the USA, along with interferometer cameras in Virginia and Massachusetts to measure winds. The winds are strongly affected but in different ways, implying that the balance forces on the atmosphere is strongly dependent on proximity to the disturbance.

We analyse the climatology of the ionosphere over Nepal based on GPS-derived vertical total electron content (VTEC) during 2008–2018. The study illustrates the diurnal, monthly, annual, seasonal and solar cycle variations in VTEC. The results show equinoctial asymmetry in TEC in maximum phases in 2014, followed by descending, ascending and minimum phases. The winter anomalies are seen during increasing and maximum phases of the solar cycle (2011–2014) from almost all stations considered.

This study concerns postmidnight ionospheric irregularities observed during low solar activity conditions. We analyze data from digisondes and optical imaging systems located in an equatorial region over Brazil. The results show that they occur under unfavorable and unexpected conditions. This work can be useful for space weather forecasting during low solar activity.

The novelty of this paper lies in the fact that it addresses the thermosphere–ionosphere coupling in a midlatitude site in north Africa. We have used Fabry–Perot measurements of thermospheric winds and wide-angle camera detection of ionospheric structures at an altitude of about 250 km. We have also used GPS data to extract the TEC over the studied area. We have focused our study on the 27 February geomagnetic storm.

The midnight temperature maximum (MTM) is a phenomenon resulting from the constructive interference of the atmospheric tides. This paper brings the analysis of a long data set (846 nights) from the NATION network along with new analysis techniques (harmonic background removal and 2-D temperature interpolation) to detect the MTM in the mid-latitude range.