the science
An eye-safe infrared beam illuminates natural aerosols in the atmosphere (such as dust, pollen and droplets) and a small fraction of the light is backscattered into a receiver. Motion of the target particles along the beam direction leads to a change in the light’s frequency through Doppler shift which is then accurately measured.
A conical scan pattern is used to move the beam and intercept the wind at different angles, building up a series of measurements around a disc of air from which the wind speed vector is obtained.
ZephIR® obtains each measurement in just 20 milliseconds, and three seconds of data are used to derive the horizontal and vertical wind speed components and wind direction. This can be repeated up to a height of 150 metres, at five user defined heights by focussing the transmitted beam.
At each height a total of 150 points of data are gathered which enhance the quality of measurement, providing additional information on turbulence essential for sites with complex terrain.
- Turbulence intensity showing the variation across the site due to complex terrain and flow conditions
- Extreme turbulence determining levels of turbulence with the potential to damage machines, or seriously degrade performance