Numerical simulation of a heterodyne Doppler LIDAR for wind measurement in a turbulent atmospheric boundary layer

Brousmiche, Sébastien [UCL] Bricteux, Laurent [UCL] Sobieski, Piotr [UCL] Macq, Benoît [UCL] Winckelmans, Grégoire [UCL]

This study concerns the modeling and the design of a monostatic heterodyne pulsed LIDAR. The heart of the system is constituted of a 1.55 mu m able to produce high pulse repetition frequency. The aim of this work is to assess its efficiency to perform accurate wind speed measurements in the low atmospheric boundary layer, from a 2-D scanning pattern, in the presence of refractive turbulence. A complete LIDAR numerical simulation technique has been developed. Its main originality is the integration of both optical and fluid dynamics numerical methods to take into account the signal coherence loss due to refractive turbulence and speckle effect as well as the fine structures of the wind field. The wind speed profiles along each line-of-sight are retrieved from the return signal using a low-order autoregressive model. An adequate averaging model is then used estimate horizontal components of the wind speed for altitudes up to 150 m.