Abstract
Abstract. Gravity waves (GWs) as well as solar tides are a key driving mechanism for the circulation in the Earth's atmosphere. The propagation of gravity waves is strongly affected by tidal waves as they modulate the mean background wind field and vice versa, which is not yet fully understood and not adequately implemented in many circulation models. The daylight-capable Rayleigh–Mie–Raman (RMR) lidar at Kühlungsborn (54∘ N, 12∘ E) typically provides temperature data to investigate both wave phenomena during one full day or several consecutive days in the middle atmosphere between 30 and 75 km altitude. Outstanding weather conditions in May 2016 allowed for an unprecedented 10-day continuous lidar measurement, which shows a large variability of gravity waves and tides on timescales of days. Using a one-dimensional spectral filtering technique, gravity and tidal waves are separated according to their specific periods or vertical wavelengths, and their temporal evolution is studied. During the measurement period a strong 24 h wave occurs only between 40 and 60 km and vanishes after a few days. The disappearance is related to an enhancement of gravity waves with periods of 4–8 h. Wind data provided by ECMWF are used to analyze the meteorological situation at our site. The local wind structure changes during the observation period, which leads to different propagation conditions for gravity waves in the last days of the measurement period and therefore a strong GW activity. The analysis indicates a further change in wave–wave interaction resulting in a minimum of the 24 h tide. The observed variability of tides and gravity waves on timescales of a few days clearly demonstrates the importance of continuous measurements with high temporal and spatial resolution to detect interaction phenomena, which can help to improve parametrization schemes of GWs in general circulation models.
Highlights
The knowledge of atmospheric waves is crucial for our understanding of the circulation in the Earth’s atmosphere
Gravity waves (GWs) and thermal tides differ in their sources
The propagation of tidal and gravity waves depends on the mean background wind as well as on the interaction of tides and gravity waves
Summary
The knowledge of atmospheric waves is crucial for our understanding of the circulation in the Earth’s atmosphere. Radar measurements of horizontal winds produce nearly continuous data sets, from which the short-term variability of gravity and tidal waves can be investigated, but only in a limited altitude range of approximately 70–100 km (Hoffmann et al, 2010). To cover the entire middle atmosphere, the combination of different lidars using several scattering mechanisms (e.g., Rayleigh and resonance scattering) is the only measurement technique which provides temperature data from the troposphere/lower stratosphere to the mesopause region or even higher with a suitable temporal and vertical resolution to resolve the short-term variability. This paper presents main features of wave activity at midlatitudes for an altitude range from the lower stratosphere to the upper mesosphere on short timescales of 10 days in May 2016 To our knowledge, this is the longest continuous data set retrieved by a RMR lidar.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
