Simultaneous ground-based observations of a large quasi 26 d wave from three different measurement sites in northern mid-latitudes

We present simultaneous observations of a remarkable planetary wave event in mesospheric temperature observed by three different ground-based mid-latitude OH spectrometers at stations in Germany (Greifswald (54° N, 13° E), Wuppertal (51° N, 7° E), and Hohenpeißenberg (48° N, 11° E)) during boreal winter 2016/2017. Additionally, temperature profile observations with the satellite instruments SABER/TIMED and MLS/Aura are used for supporting information on the global distribution of the wave event. The observed wave had a period of about 26 d and an amplitude of partly up to about 20 K. The satellite temperature observations confirmed that the wave signature exhibited all the characteristics of the well known Rossby (1,4) normal mode oscillation. To the best of our knowledge this is the first study reporting on such a strong Rossby (1,4) wave in the middle atmosphere of the Northern Hemisphere. The wave signature was also identified in atomic oxygen mixing ratios in the mesopause region and lower thermosphere observed with SABER illustrating the importance of such wave events not only for the temperature distribution but also for the temporal variation of trace-gas distributions.