The MU radar study of nonlinear advective accelerations in the lower and middle atmosphere

A multi-beam method was used to calculate zonal, s(x), and meridional, s(y) , nonlinear advective accelerations from the MU radar observations with the antenna beam pointing in 9 directions. The results of simultaneous measure ments of s(x) and s(y) in the tropo-stratosphere (altitudes 2 -- 18 km) and in the mesosphere (65 -- 80 km) in April 1999 are presented. Short-period variations of s(x) and s(y) may show regions of increased generation of atm ospheric gravity waves. The wave generation increases with the increase in the mean wind and have ma?;ima at the altitudes, where the maxima of tropos pheric and mesospheric jets are located. The dependence of s(x) and s(y) on the mean wind is weaker in the mesosphere than in the tropo-stratosphere. (C) 2001 Elsevier Science Ltd. Ali rights reserved.