Operational reliability and accuracy of SODARs in wing vortex characterization

Acoustic radars, or SODARs, obtain strong reflections of acoustic pulses from atmospheric turbulence, and the Doppler shift allows wind speeds to be measured. A companion paper shows that high-quality real-time measurements of wing vortex strength and position can be obtained using well-established SODAR technology. Here we review and evaluate those situations known to cause reduced data availability: low-turbulence; rainfall; and high background noise levels. The relationships between SODAR signal strength and the relevant environmental parameters are derived based on operational experience in a range of sites and applications. The climatology of these parameters for several major airports is then estimated and used to obtain measures of likely performance of SODARs as operational tools for 'now-casting' vortex behaviour at these airports. It is shown that, because of the distinctive and strong vortex signals, SODAR offer a viable technology for routine vortex monitoring.