SODAR

Sodar (Sound Detection And Ranging) is a remote sensing technique for measuring wind speed in the three dimensional wind vector to heights of about 200 m above ground level and with a height resolution of 5 to 10 meters. Due to the mobility of the mini-sodars, it is possible to determine the strongly varying wind conditions in complex terrain.

For a reliable prediction of wind energy potential, a Sodar measuring campaign carried out over a few months is the ideal complement to a 12 month met mast wind measuring system.

Sodar with equipment container

Generator

Delivery

The measurements are based on sound pulses which are emitted from the device and reflected from the inhomogeneous (turbulent) air. The Doppler effect causes a frequency shift in the reflected sound pulse from which the speed and distance parallel to the sound beam can be calculated. By sending three beams into different directions the wind speed vector can be calculated from the reflected sound.

Sodar Campaign with technical specifications

Instrument: Aero Vironment Mini Sodar
Measuring Period: 15 June 1999 to 29 September 1999
Minimum Altitude: 15 m
Maximum Altitude: 200 m
Height Resolution: 5 m
Transmit Frequency used: 4500 Hz
Averaging interval used: 10 min / 1 min
Wind Speed Accuracy: < 0.25 m/s
Wind Direction Accuracy: +/- 2 deg

A detailed report can be downloaded here.