Dynamics of the thermal structure of the lower atmosphere above Tomsk from the data of acoustic sounding

Abstract

In the present work, results of investigations into the thermal structure of the atmospheric boundary layer from the data of acoustic sounding are given. Acoustic sounding was performed by the Zvuk-3 sodar in the suburbs of Tomsk in different seasons of 2005-2007. The stratification type (class of atmospheric stability), mixing layer height, and temperature inversion layers together with their thickness and heights of their upper and lower boundaries were determined. Their statistical characteristics were also calculated. The characteristics of temperature stratification were in good agreement with the previously obtained data. Thus, in winter the number of surface inversions was maximal. In our case, in December of 2005-2007, the surface inversions were observed in more than 50% of cases. The height of the lower boundary of elevated inversions was in the altitude range 50-100 m, the upper boundary of the elevated inversion was in the altitude range 140-200 m. The average thickness of elevated inversions in December was about 90 m. In summer, inversions were observed mainly at night, because unstable stratification prevailed in the afternoon. The average height of the lower boundary of the elevated inversion in June was 70 m, and that of the upper boundary was 230 m. The ABL structure characteristics obtained with the acoustic radar can be used to predict climatic prerequisites for atmospheric pollution events.