A statistical analysis of the data of 10 year observations with the Middle and Upper (MU) atmosphere radar gives information about seasonal variations of the intensity of irregular wind disturbances, which are different in the troposphere and mesosphere. A comparison of seasonal variations of internal gravity wave intensity observed by the MU radar with a numerical model of wave spectrum propagation explains the differences of the seasonal variations and gives information about vertical distribution of the intensity of hydrodynamic wave sources. Discussed are the MU radar measurements of nonlinear advective accelerations in the tropo-stratosphere, which reflect the activity of nonlinear wave generation.