Mesosphere/lower thermosphere winds measured with nearby SKiYMET meteor radars at Collm and Juliusruh, and comparison with Kazan winds

Mesosphere/lower thermosphere winds have been measured by VHF meteor radars at Collm (51.3°N, 13.0°E) and Juliusruh (54.6°N, 13.4°E) for more than a decade. We compare hourly winds from the two radars. We find that the mean meridional wind difference is small and amounts to less than 2 or 3 m/s in winter or summer, respectively. Zonal hourly wind differences are also smaller than 4 m/s. The standard deviations of the differences are in the order of 15 m/s, and they slightly increase with height. The hourly winds at the two sites are strongly correlated, and the remaining differences are probably mainly due to gravity waves and mesoscale wind structures. We also included meteor radar winds from the Kazan radar (56°N, 49°E), which was installed in 2015. Comparison of the hourly mean Juliusruh winds with those from the Kazan meteor radar also show mostly small mean differences, but the hourly winds are uncorrelated. The individual differences are much larger, due to the influence of tides and planetary waves at the different longitudes of these stations.