We use a novel technique to infer long-term compositional changes to the thermosphere from the annual variation of the ionospheric F2 region. A global analysis of these data reveal that long-term changes differ between geographic locations in a way that is very similar to the observed variation in the ionospheric response to increased atmospheric CO2 levels. In the absence of long-term measurements of thermospheric composition, further, detailed, modelling work is required.

In this paper we present further observations of the solar-wind particles being accelerated to rather higher energies while passing through the HCS or a current sheet formed at the front of an interplanetary coronal mass ejection. This additional acceleration can explain the anticorrelation of ion and electron fluxes frequently observed around the ICME’s leading front. This acceleration can also provide a plausible explanation of the appearance of bidirectional strahls.

This paper addresses the background of electron density (Ne) and temperature (Te and their relationship during local nighttime based on DEMETER satellite data. It also discusses the enhanced negative correlation of Ne and Te around strong earthquakes and the possible electric-field-coupling mechanism as well as digital calculation.

The forcings of the semiannual oscillation (SAO) of the tropical zonal wind in the stratopause region are investigated based on ERA-Interim reanalysis and HIRDLS satellite observations. In particular, the SAO driving by mesoscale gravity waves is estimated directly from satellite observations of gravity waves. Our study confirms previous indirect evidence that planetary waves dominate during the westward driving of the SAO, while gravity waves mainly provide eastward forcing.

In this study we use two-loop model SCW (SCW2L) to quantitatively investigate distortion of the ionospheric footpoint pattern in response to changes of different SCW2L parameters. Calculation results show that SCW-related footprint shifts result in formation of auroral bulge and westward travelling surge and may contribute to rotation of auroral streamers, and that SCW2L combined with the AM03 model nicely describes the azimuthal progression and the observed magnitude of the auroral expansion.