During the night, in the F region, equatorial ionospheric irregularities manifest as plasma depletions observed by satellites and may cause radio signals to fluctuate. We checked the distribution traits of ionospheric F-region irregularities in the low latitudes using 16 Hz electron density observations made by the faceplate onboard Swarm satellites. Using the high-resolution faceplate data, we were able to identify ionospheric irregularities of scales of only a few hundred metres.

The diurnal cycles of precipitation are not phase-locked to daily insolation; rather, their occurrences are associated with propagating systems. The early morning precipitation (EMP) events are distinctly characterized by large mean amplitudes and randomly distributed phases also marked by strong connectivity between precipitation systems over land and ocean. This implies that, even for a 24 h lead time, probabilistic forecast may be necessary to assess the hazard of heavy precipitation.

The paper analytically and numerically treats the new theoretical basis for ground-based and satellite monitoring of the most powerful processes in the lower atmosphere and Earth (hurricanes, earthquakes, etc.), solar-wind magnetosphere (magnetic storms) and ionosphere (lightning discharges, thunderstorms, etc.). This can be provided by the determination of phases and amplitudes of radio waves in the Earth and ionosphere. In perspective, damage from the natural disasters can be decreased.

During the most intense storm of solar cycle 24, the magnetosphere–ionosphere interaction, which is primarily associated with field-aligned currents (FACs), was much stronger than usual. Measurements onboard the low-latitude polar-orbiting Swarm satellites have shown that the intensities of FACs increase dramatically during the storm-time substorms. The extreme values of 1 s (7.5 km width) FACs reach 80 μA m⁻². The lowest latitude of the FAC region is limited to 49–50 MLat.

An equatorial plasma bubble (EPB) event, emerging near dawn and developing after sunrise, was simultaneously observed by an all-sky imager and the global navigation satellite system (GNSS) network. The observed EPBs showed westward drifts, different from post-sunset EPBs. The EPBs occurred in the recovery phase of a geomagnetic storm, possibly playing a key role in initializing their developments. The results provide a new perspective of EPBs, enriching our knowledge of ionospheric irregularity.

This study correlates ionospheric parameters with the integrated solar radiation for an analysis of the delayed ionospheric response in order to confirm previous studies on the delay and to further specify variations of the delay (seasonal and spatial). Results also indicate the dependence on the geomagnetic activity as well as on the 11-year solar cycle. The results are important for the understanding of ionospheric processes and could be used for the validation of ionospheric models.

Oxygen ions are an important element in the mass and energy transport in the magnetospheric dynamic process during intense substorms (AE  >  500 nT). We did this work to better understand the O⁺ at the dusk flank magnetopause varying with solar wind conditions and AE index during intense substorms. The results show the O⁺ abundance at the duskside magnetopause has a corresponding relation to that in the duskside near-Earth plasma sheet.

Spatial-energy distributions of the stationary fluxes of protons, helium ions, and ions of the carbon–nitrogen–oxygen (CNO) group in the Earth's radiation belts (ERBs) are considered here using data from satellites from 1961 to 2017. It is found that the results of these measurements line up, with some regular patterns present. Solar-cyclic (11-year) variations in the distributions of protons, helium ions, and CNO group ion fluxes in the ERB are presented.

The additional transfer of momentum and energy induced by locally breaking gravity wave hotspots in the lower stratosphere may lead to a destabilization of the polar vortex, which is strongly dependent on the position of the hotspot. The simulations with a global circulation model show that hotspots located above Eurasia cause a total decrease in the stationary planetary wave (SPW) activity, while the impact of hotspots located in North America mostly increase the SPW activity.

Severe meteorological storm Fabienne passing above central Europe was observed. Significant variations of atmospheric and ionospheric parameters were detected. Above Europe, stratospheric temperature and wind significantly changed in coincidence with frontal transition. Within ionospheric parameters, we have detected significant wave-like activity shortly after the cold front crossed the observational point. During the storm event, we have observed strong horizontal plasma flow shears.

A unique stratospheric balloon-borne observation of noctilucent clouds (NLCs) was performed at night on 5–6 July 2018. A sounding balloon, carrying the NLC camera, reached 20.4 km altitude. NLCs were observed from the stratosphere at large scales (100–1500 km) for the first time. Propagations of gravity waves of various scales were registered. This experiment is rather simple and can be reproduced by the broad geoscience community and amateurs, providing a new technique in NLC observations.

The magnetic field that is carried by the solar wind slowly decreases in strength as it moves further from the Sun. However, there are sometimes localized decreases in the magnetic field strength, called magnetic holes. These are small structures where the magnetic field strength decreases to less than 50 % of the surroundings and the plasma density increases. This paper presents a statistical study of the behaviour of these holes between Mercury and Venus using MESSENGER data.

The paper shows a statistical analysis of Pc3 and Pc5 pulsations recorded during 60 d (September to November 1994) by a meridional magnetometer profile crossing the dip equator in central South America. This is the first time that a detailed mapping of latitudinal dependence of pulsation amplification at very low latitudes has been performed. One of the most prominent findings is that our equatorial Pc5s might be related to both horizontally and vertically incident MHD waves in the ionosphere.

In this work, we studied the HILDCAA disturbance time effects in the TEC by analyzing local time and seasonal dependences, and the influences of the solar wind velocity on a sample of 10 intervals occurring in 2015 and 2016. The main results show great variability in the hourly distribution of the dTEC between one interval and another, seasonal behavior different from that presented by geomagnetic storms, and interestingly no relation between the dTEC disturbances and the magnitude of the HSS.

High-resolution measurements of the magnetic profiles of collisionless shocks in space show that large amplitude oscillations appear on the high-magnetic field side. The positions and relative amplitude of these oscillations are shown theoretically to vary in accordance with the potential jump at the shock crossing. The theoretically predicted variety is confirmed by observations.

This is the first survey of pulsating auroras which is differentiated by type. Pulsating auroras are found to be almost always an early-morning phenomenon and are almost entirely lacking persistent structuring before midnight. Long-lived patches which are known to move with convection primarily appear after midnight. These patches are a less common form of pulsating aurora and are found to originate from the inner magnetosphere, in agreement with past observations of their source region.