SODAR MEASUREMENTS OF WIND SPEED AND WIND DIRECTION ABOVE BIG CITY (MOSCOW)

The results of long-term measurements both of wind speed, and of wind direction in the lower air layer up to 500 m height above Moscow city with the use of Doppler sodar are presented for period from 2004 to 2009. Excellent spatial and temporal resolution of the sodar data allows for studying a fine-structure of the wind stratification in the atmospheric boundary layer in details. The main tendency of the wind speed annual course is higher values in cold period and comparatively smaller ones in warm period. Separate monthly-averaged values of wind speed in the air layer from 40 to 200 m vary in limits from 4 to 7 m/s of approximately. The maximal-maximorum value of wind speed above Moscow (up to the level of 500 m) averaged for 10 minutes has been found thrice as 31 m/s. The statistical distribution of wind speed is characterized by positive skewness and is close to the logarithmically normal law. A mode of the total wind speed distribution is nearly of 4 m/s. Periodogram analysis demonstrates statistically significant cyclicity at the wind speed dynamics connected with synoptic period (several days). Diurnal cyclicity is weaker – at least, in winter. The most frequent wind in Moscow city is South-Western with a speed from 5 to 10 m/s, the rarest – North-Eastern. Key words: acoustic remote sensing, atmospheric boundary layer, wind profiles, statistical distributions, spectral analysis, synoptic perio