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- ItemLocal stratopause temperature variabilities and their embedding in the global context(Göttingen : Copernicus Publ., 2020) Eixmann, Ronald; Matthias, Vivien; Höffner, Josef; Baumgarten, Gerd; Gerding, MichaelThe stratopause is by definition the transition between the stratosphere and mesosphere. During winter the circulation at mid-latitudes and high latitudes in the stratosphere is mainly driven by quasi-stationary planetary waves (PWs), while the circulation in the mesosphere is mainly driven by gravity waves (GWs). The question arises of whether PWs or GWs dominate the variability of the stratopause. The most famous and dramatic variability of the middle atmosphere is a sudden stratospheric warming (SSW) generated by PWs interacting with the polar vortex. A similar phenomenon but smaller in magnitude and more regional is stratopause temperature enhancements (STEs) initially observed by local measurements and generated by breaking PWs. Thus it seems that PWs dominate the variability of the stratopause. In this study we want to quantify to which extent quasi-stationary PWs contribute to the stratopause variability. To do that we combine local lidar observations at Kühlungsborn (54∘ N, 11∘ E) and Andenes (69∘ N, 16∘ E) with global MERRA-2 reanalysis data bringing the local variability of the stratopause into the global context. Therefore we compare the temperature time series at Kühlungsborn and Andenes at 2 hPa, the altitude where STEs maximize, with characteristics (amplitude and phase) of PWs with wave numbers 1, 2 and 3. We found that for Kühlungsborn and Andenes 98 % of the local day-to-day variability of the stratopause can be explained by the variability of PWs with wave number 1, 2 and 3. Thus, the winter stratopause day-to-day variability is highly dominated by the variability of PWs.
- ItemHistory of the Juliusruh ionospheric observatory on Rügen(Göttingen : Copernicus Publ., 2016) Weiß, J.The history of the Juliusruh ionospheric observatory on Rügen is closely connected to the history of ground-based ionospheric sounding. After a short introduction to the ionospheric research and the sounding technique, the founding of the Juliusruh station in 1954 and its development until today are described. The different methods of ground-based sounding – as far as they apply to Juliusruh – are briefly discussed. The condition of life and work in a small team on the island of Rügen, remote from the respective parent institute, is also the subject of this article, whose author headed Juliusruh Station from 1965 to 2004.