SoDAR 101

With our recent acquisition of Atmospheric Systems Corporation we have started to receive questions asking about SoDAR technology and how wind profiling works.

SoDAR is an acronym which stands for Sonic Detection And Ranging.  The term refers to an instrument which uses sound to measure wind speed and direction at altitudes up to 3,000 ft. 

SoDAR operates by emitting a short sound pulse, then listening to the atmospheric echo from the pulse. The echo is a result of the continuous interaction between the outward propagation of acoustic energy and atmospheric turbulence. The echo, when received by the SoDAR is processed for its frequency content.  A change in frequency is associated with the turbulent movement of the atmosphere and the wind field above the SoDAR antenna.  Using the Doppler shift principles, the echo frequency of the pulse will be greater than the emission frequency if the movement of the wind field is toward the SoDAR antenna.  If the wind field movement is away from the antenna the echo frequency will be lower than the pulse frequency.

The outgoing pulse is not affected in frequency until it is echoed by the interaction with atmospheric turbulence and bounced back to the microphones of the antenna. This observed fact enables a frequency coherent SoDAR to associate a particular frequency shift with a particular distance from the antenna. Using information from three different directions (and decoding the data in terms of its first order geometry, the altitude gated frequencies enable a full wind profile to be measured.

For more information about our SoDAR Systems please contact us at sales@minisodar.com or sales@metone.com