OPINION OF THE LEADER   to the qualification master work of the student of the atmospheric physics department of Saint-Petersburg state university Popov Andrej Alexeevich “The variability of mesoscale waves in the middle atmosphere according to the data of optical measurements”  In the qualification work, A. A. Popov made the analysis of the observations of variations in characteristics of the night emission of hydroxyl at altitudes 80  –  100 km for the purpose of the study of seasonal and inter-annual changes in the intensity of the mesoscale variability in the middle and upper atmosphere. For the first time, the method of the digital filtration of variations with the periods 0.4  –  5.4 hr is used for this purpose by calculating the differences between the consecutive values of the characteristics of night glow, averaged over 15-,  30-,  60- the 120- minute intervals. This procedure was not used earlier for the analysis of night glows. With this method, data of the measurements of the nightglow hydroxyl emission with different spectroscopic instruments in Alma-Ata, Irkutsk and Zvenigorod in the years 2004  –  2017 were analyzed.      Seasonal and inter-annual changes in the monthly-mean values and mesoscale variances of the emission intensity and rotational temperature of hydroxyl were determined. Seasonal changes in the characteristics reveal differences at different stations, which can be explained by latitudinal dependence and differences in the geometry of measurements at the different stations. Interannual changes are caused by long-lived trends and influence of solar activity. A reason for mesoscale variations in characteristics of nightglows could be internal gravity waves (IGWs), parameters of which are determined in the qualification work.      During the work on the theme the master’s degree candidate studied IGW theory and found formulas for estimations of amplitudes and potential wave energy from the results of measuring the dispersions of mesoscale variations in the temperature. He became acquainted with the existing procedures of the data analysis of the observations of nightglows of the upper atmosphere and developed programs for the numerical filtration of the observed values of intensity and rotational temperature of hydroxyl. Masters degree candidate developed programs in the language FORTRAN, carried out the calculations of average characteristics and dispersions of variations in the nightglows in the different spectral ranges at the stations Alma Ata, Irkutsk and Zvenigorod in the years 2004 – 2017. He determined seasonal and interannual changes in the characteristics indicated. According to the results of work, one paper is submitted and accepted for the press and two reports at the international conferences are made.       In the time of studies, A. A. Popov demonstrated skills and habits, which are enough for the solution of the contemporary scientific and computational problems of atmospheric physics. I consider that the study of A. A. Popov corresponds to the requirements, presented to the qualification masters work and deserves appreciation.  Scientific leader, Professor of the atmospheric physics Department of SPbSU, PHD                                                                N. M. Gavrilov