Investigations on convective boundary layer turbulence using SODAR data

Abstract

Acoustic sounding (SODAR) data collected in convective conditions were analysed to estimate high order statistics of the vertical velocity in the lower half of the Convective Boundary Layer (CBL). Limitations of the instrumentation system were assessed and it turned out that spatial and temporal fi ltering have little effect on skewness and kurtosis, and do not prevent a reliable evaluation of these parameters, provided that a suffi ciently long time period is analysed. Vertical profi les of skewness are grouped into two broadly defi ned classes, one which increases almost linearly with height and the other which shows a constant-with-height behaviour. Both behaviours are shown to be consistent with different parameterisations used in literature. Kurtosis profi les are found to be fairly well described adopting a quadratic relationship between skewness and kurtosis, provided that the correct parameterisation of skewness is used.