Small-scale auroral features are still being discovered and are not well understood. Where aurorae are caused by particle precipitation, the newly reported fragmented aurora-like emissions (FAEs) seem to be locally generated in the ionosphere (hence, aurora-like). We analyse data from multiple instruments located near Longyearbyen to derive their main characteristics. They seem to occur as two types in a narrow altitude region (individually or in regularly spaced groups).

Magnetosheath jets are high-velocity features within the Earth's turbulent magnetosheath, separating the Earth's magnetic domain from the solar wind. The characteristics of the jets are difficult to assess statistically as a function of their lifetime because normally spacecraft observe them only at one position within the magnetosheath. This study first confirms the accuracy of the model used, Vlasiator, by comparing it to MMS spacecraft, and then carries out the first jet lifetime statistics.

The composition of the upper atmosphere has been difficult to measure with localised observations relying on spacecraft, suborbital rockets or measurements of airglow from ground-based observatories. The height profile of ionisation within the neutral upper atmosphere is influenced by the composition of the neutral gas. We present a method for determining the neutral upper-atmosphere composition from measurements of the ionisation profile and compare these with spacecraft measurements.

The paper focuses on the differentiation between large clusters of thunderstorms and smaller ones, such as supercells. The analysis was also enriched by DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite flybys, which granted us better insight into the origins of these phenomena. The main conclusion from the paper shows that the more condensed in size the thunderstorm is, the stronger discharge it generates.

The knowledge of decadal temperature trends in the stratosphere, mesosphere, and lower thermosphere (20 to 100 km) is important for both scientific and practical reasons and for the relation to climate change. Almost all long-term measurements are made at fixed or limited local time intervals. The differences among the various measurements can be significant. Our results show that at least some of these differences may be due to the different local times at which the temperatures are measured.

We investigate the delayed ionospheric response using the observed and CTIPe-model-simulated TEC against the solar EUV flux. The ionospheric delay estimated using model-simulated TEC is in good agreement with the delay estimated for observed TEC. The study confirms the model's capabilities to reproduce the delayed ionospheric response against the solar EUV flux. Results also indicate that the average delay is higher in the Northern Hemisphere as compared to the Southern Hemisphere.

Numerical modelling is used to simulate atmospheric circulation and calculate residual mean meridional circulation (RMC) during sudden stratospheric warming (SSW) events. Calculating the RMC is used to take into account wave effects on the transport of atmospheric quantities and gas species in the meridional plane. The results show that RMC undergoes significant changes at different stages of SSW and contributes to SSW development.

The commented publication by Janzhura and Troshichev (2011) constitutes an essential part of the basis for the IAGA endorsement by Resolution 3 (2013) of PC index calculations. However, there is strong disagreement between indications of near real-time methods in the title, abstract, statements in the text, and figure captions, as well as in illustrations of results in the article compared to results from recalculations of the relations by rigorous use of the presented near real-time procedure.