The paper presents the variability in thermal tides in the middle atmosphere from temperature observations as well as from horizontal wind data using a new diagnostic approach which takes into account a possible intermittency of tides. The data are analyzed from a local as well as from a global perspective to distinguish between different tidal modes. Surprisingly, there are dominating tidal modes, which are seen in the local data, and a phase relation between temperature and winds is evaluated.

We study how the Earth's space environment responds to two different amplitude interplanetary coronal mass ejection (ICME) events that occurred in 2012 and 2014 by using the GUMICS-4 global MHD model. We examine local and large-scale dynamics of the Earth's space environment and compare simulation results to in situ data. It is shown that during moderate driving simulation agrees well with the measurements; however, GMHD results should be interpreted cautiously during strong driving.

This paper concerns the question of whether the maximum Earth ring current strength exists and at which moment the ring current can start to break up, thus making a new mechanism of the ring current decrease during the magnetic storm. We study this effect using the Stormer theory of particle motion. After transition of critical strength, Stormer's inner trapping region opens up and the ring current charged particles get the opportunity to leave it, thus decreasing the current strength.

In this work we present an analysis of the dynamics of suprathermal ions of different masses (H⁺, He⁺, O⁺) during prolonged dipolarizations in the near-Earth magnetotail according to Cluster/RAPID observations in 2001–2005. All dipolarizations from our database were associated with fast flow braking and consisted of multiple dipolarization fronts (DFs). We found statistically that fluxes of suprathermal ions started to increase ~ 1  min before the dipolarization onset and continued.

We observe the planetary and gravity wave activity in the vertical profile of ozone at the mid-European ozonosonde stations The performance of the used detection method is satisfactory. There are differences in the following characteristics of the structure caused by the planetary and gravity wave: the annual variation, the size, and the vertical distribution. The results are influenced by the ozonosonde vertical resolution only for small and medium structures.

Simulations of locally breaking gravity wave hot spots in the stratosphere show a suppression of wave propagation at midlatitudes, which is partly compensated for by additional wave propagation through the polar region. This leads to a displacement of the polar vortex towards lower latitudes. The effect is highly dependent on the position of the artificial gravity wave forcing. It is strongest (weakest) for hot spots at lower to middle latitudes (higher latitudes).

We propose that the temperature of the Na exosphere of Mercury near the subsolar point is not at high as proposed in previous works. Using a numerical model and the appropriate energy distributions for each release mechanism, we can explain observations made by MESSENGER in April 2012. Our results show that close to the surface, the dominant release mechanism for Na is evaporation due to the solar irradiation, and at high altitudes the best candidate is the release by micro-meteoroid impacts.

In this paper, for the first time, absolute gravity wave momentum flux (GWMF) on temporal scales from terannual variation up to solar cycle length is investigated. The systematic spectral analysis of SABER absolute GWMF is presented and physically interpreted. The various roles of filtering and oblique propagating are discussed, which is likely an important factor for MLT dynamics, and hence can be used as a stringent test bed of the reproduction of such features in global models.

The sun’s radiation exhibits a cycle with a period of ~11 years. We need to understand how the atmospheric temperature and ozone react to this solar variation, as it can affect climate. The response depends on energy transfer, chemical reactions, and atmospheric motions. There is no consensus as to some details. For example, the responses depend on the local times of the variations. This study provides results of effects of local time on the responses, from 20 to 100 km, based on measurements.

To simulate the vertical propagation of atmospheric waves, experimental data on pressure variations at the Earth's surface are used. These data are associated with the meteorological source. The simulation results have allowed for the first time estimates of the amplitudes of temperature wave disturbances in the upper atmosphere caused by waves from the atmospheric front. The simulations have been performed using the Lomonosov supercomputer.

We provide an analysis of processing setting impacts on tropospheric gradients estimated from GNSS observation processing. These tropospheric gradients are related to water vapour distribution in the troposphere and therefore can be helpful in meteorological applications.

The paper investigates the occurrence of polar mesosphere summer echoes (PMSEs) over a solar cycle. Besides the statistical study of the layered PMSE occurrence ratio, the authors propose a method to deal with the discontinuous EISCAT radar measurements. The method makes it easier to establish a relationship between the layered PMSEs and solar and geomagnetic activities. The paper presents a relatively large data set that brings results. It can be recommended in future research on the PMSEs.

The fundamental mode of oscillations of the solar atmosphere, f-mode, plays an important role in solar physics. At an early stage of observation, it was found that its frequency is related to the wavelength by a ratio characteristic of waves on the surface of deep water. Subsequent observations revealed its inaccuracy. We derived waves with a different frequency–wavelength ratio and compared them with other possible waves of this type in both the solar and terrestrial atmosphere.

This paper describes the aerosol measurement setup and results obtained from the BEXUS18 stratospheric balloon within the A5-Unib (Advanced Atmospheric Aerosol Acquisition and Analysis) experiment performed on 10 October 2014 in northern Sweden (Kiruna). The experiment and the results here presented broaden the understanding of the processes linking the presence of charges with particles all over the vertical heights from the ground to the stratosphere.

Flow channel extending in north–south directions is produced in the initial pulse of Pi2 pulsations associated with the field line dipolarization. Drifts in the ionosphere of the order of kilometers per second accumulated plasmas at the low-latitude end of the flow channel. The plasma compression in the ionosphere produced field-aligned currents, parallel electric fields, and auroral expansion. We called the compressive ionosphere a "dynamic ionosphere".

We investigated the statistical relationship between solar activity and the occurrence rate of major sudden stratospheric warmings (MSSWs). For this purpose, the 10.7 cm radio flux (F10.7) has been used as a proxy for solar activity. The calculations have been performed based on two datasets of central day (NCEP–NCAR-I and combined ERA) for the period from 1958 to 2013. The analysis revealed a positive correlation between MSSW events and solar activity.