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. The Middle Atmosphere Alomar Radar System (MAARSY) installed at the island ofAndoya has been run for continuous probing of atmospheric winds in theupper troposphere and lower stratosphere (UTLS) region. In the current study,we present high-resolution wind measurements during the period between 2010and 2013 with MAARSY. The spectral analysis applying the Lomb–Scargleperiodogram method has been carried out to determine the frequency spectra ofvertical wind velocity. From a total of 522 days of observations, thestatistics of the spectral slope have been derived and show a dependence onthe background wind conditions. It is a general feature that theobserved spectra of vertical velocity during active periods (with windvelocity >  10  m s−1 ) are much steeper than during quiet periods(with wind velocity  10  m s−1 ). The distribution of spectral slopesis roughly symmetric with a maximum at − 5/3 during active periods, whereas avery asymmetric distribution with a maximum at around − 1 is observed duringquiet periods. The slope profiles along altitudes reveal a significant heightdependence for both conditions, i.e., the spectra become shallower withincreasing altitudes in the upper troposphere and maintain roughly a constantslope in the lower stratosphere. With both wind conditions consideredtogether the general spectra are obtained and their slopes are compared withthe background horizontal winds. The comparisons show that the observedspectra become steeper with increasing wind velocities under quietconditions, approach a spectral slope of − 5/3 at a wind velocity of 10  m s−1 andthen roughly maintain this slope ( − 5/3) for even stronger winds. Ourfindings show an overall agreement with previous studies; furthermore,they provide a more complete climatology of frequency spectra of verticalwind velocities under different wind conditions. Keywords. Meteorology and atmospheric dynamics (turbulence; waves and tides)

High-resolution vertical velocities and their power spectrum observed with the MAARSY radar – Part 1: frequency spectrum