Vertically pointing sodar

We installed a vertically-pointing single-antenna version of the LATAN-3M sodar system at the coastline. The sodar has a frequency-coded sounding signal which allows several measurements per range gate thus providing higher data availability and quality compared to single-frequency signals. The frequency-coded signal includes eight consecutive 50 ms pulses with frequencies of 3.32, 3.46, 3.58, 3.66, 3.76, 3.9, 4.02, and 4.13 kHz. The vertical measurement range is 10 to 340 m.
The measured parameters include vertical velocity with a resolution of 3 s and the signal-to-noise ratio determined as the ratio of the peak of the spectrum of the return signal relative to the height of the adjacent bands around it. From the data it is possible to derive for example profiles of mean vertical velocity and its variance. In case of a shallow ABL, the signal-to-noise ratio can be used to determine the ABL height. This type of sodar has been previously used to detect wind-shear driven turbulence, convective turbulence, strong katabatic flows and moist air advection with wave structures in the stably stratified boundary layer.