Long-term changes and trends in the upper atmosphere—An introduction

Increasing concentration of greenhouse gases affect the entire atmosphere, not only the troposphere. The special issue is devoted to long-term changes and trends in the upper atmosphere, i.e. in the mesosphere, thermosphere and ionosphere, and partly also in the stratosphere. Such long-term changes and trends are caused first of all by increasing concentration of greenhouse gases but other drivers, namely stratospheric ozone changes, changes of water vapour concentration in the stratosphere and mesosphere, long-term changes of geomagnetic activity and secular changes of Earth's magnetic field. This paper provides introduction to the special issue, giving very brief general information on global change of the upper atmosphere and introducing individual papers of the special issue.