DOPPLER SODAR MEASUREMENTS OF VERTICAL WIND VELOCITY

M. A. Lokoshchenko, V. G. Perepyolkin, and N. V. Semyonova

A method for Doppler measurements of the vertical wind velocity W and the corresponding technique based on the ECHO-1 vertical sodar are described. The main difference from analogous designs is the principle of noise filtering from the useful signal by means of analysis of the received sound wave phase (not amplitude). Results are presented of comparison of sodar and direct (contact) measurements of the radial wind velocity at the meteorological tower in Obninsk. In 2000, at Moscow State University (MSU), continuous recording of W started, with a measurement threshold limit of 0.01 m/s. The diurnal cycle of this quantity at levels up to 200—300 m is discussed using measurement data for one month. At midday, there is a general tendency to lifting motions with acceleration, supposedly associated with movements of separate thermals under buoyancy. In the evening, as free convection decays, the tendency to weak sinking motions prevails. The amplitude of the vertical wind velocity gradually grows with height up to a 150-m level. The methodological basis of sodar data analysis is discussed.