Authors: G. Baumgarten, M. Almowavy, K. Baumgarten, E. Becker, J. Fiedler, M. Gerding, F.-J. Lübken, I. Strelnikova

Gravity waves (GW) are essential for transferring energy from lower to the upper atmosphere. One method to study the activity of gravity waves is to estimate their potential energy (GWPED) from temperature profiles observed by lidar or satellite. We make use of two lidar instruments ad mid to high latitudes to measure temperatures in the upper atmosphere within the altitude range of 30 to 80 km. One instrument is located in Kühlungsborn, Germany (54N) and the second is part of the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) in Andenes, Norway (69N). Both lidars make use of advanced spatial and spectral filtering allowing for measuring temperatures up to the mesosphere during day and night. We have applied the same data processing to extract GWPED from both data-sets and investigated observational filters by using three different methods for extracting GW fluctuations: constant mean background, temporally filtered and vertically filtered. We addressed the seasonal variability of GWPED over ALOMAR and Kühlungsborn within the period of 2012 – 2016. From latitudinal comparison we found that GWPEDs are surprisingly similar qualitatively and quantitatively. A seasonal behavior is clear in the vertically filtered data with a winter to summer ratio of factor of 3 however, is not pronounced in the temporally filtered data in both locations. Additionally, the climatology of GWPED from Lidars was compared with the one calculated from SABER satellite observations, and the results are indicating the same characteristics. The same observational filters were applied to the GW resolving model KMCM allowing for investigation the horizontal characteristics of observational filters and the effects of the observed GW.