IFU operates a MiniSODAR for probing the lower 200 m of the boundary layer with a vertical resolution of 5 m, and a "long-distance" SODAR which can measure up to more than 1000 m above ground with a vertical resolution between 20 and 50 m. The MiniSODAR is used for the detection of nocturnal cold air flows, pathways of fresh rural air entering cities, structures in stable nocturnal boundary layers and for the determination of parameters needed for dispersion modelling and wind energy applications. The long-distance SODAR can monitor the boundary layer during its diurnal course. Convective structures which are present over the whole vertical extend of the boundary layer become visible. Depending on noise and meteorological conditions 1300 m above ground can be reached. Both measuring devices determine the three components of the wind field and turbulence parameters.