ZephIR - how does it work?

Dr Michael Harris, Senior Scientist at Natural Power, has spent over a decade working in the field of lidar research and design. Michael was fundamental in the design concept of ZephIR at one of europe’s leading research and development institutes. Below, he outlines the principles of lidar.

“An eye-safe infrared beam illuminates natural aerosols in the atmosphere (such as dust, pollen and water droplets) and a small fraction of the light is back scattered 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 one second of data can be used to derive the horizontal and vertical wind speed components and wind direction. This can then be repeated from 10 metres up to a height of 200 metres, at five or more user-defined heights by focussing the transmitted beam.”

Michael is invited to present lidar papers and tuition sessions within a wide range of organisations across Europe and North America. He has conducted fundamental optics research at JILA (Boulder, Colorado) and the University of Essex.