Four Methods for LIDAR Retrieval of Microscale Wind Fields

Abstract

This paper evaluates four wind retrieval methods for micro-scale meteorology applications with volume and time resolution in the order of 30 m 3 and 5 s. Wind field vectors are estimated using sequential time-lapse volume images of aerosol density fluctuations. Suitably designed mono-static scanning backscatter LIDAR systems, which are sensitive to atmospheric density aerosol fluctuations, are expected to be ideal for this purpose. An important application is wind farm siting and evaluation. In this case, it is necessary to look at the complicated region between the earth's surface and the boundary layer, where wind can be turbulent and fractal scaling from millimeter to kilometer. The methods are demonstrated using first a simple randomized moving hard target, and then with a physics based stochastic space-time dynamic turbulence model. In the latter case the actual vector wind field is known, allowing complete space-time error analysis. Two of the methods, the semblance method and the spatio-temporal method, are found to be most suitable for wind field estimation.

Investigating Suppression of Cloud Return with a Novel Optical Configuration of a Doppler Lidar

“…Since then, several generations have been released, and now the lidars can be precisely focused up to a height of 200 m to reconstruct 3D wind vectors from the conical scanning at different altitudes. Currently, cw lidars are widely applied in wind energy for wind field retrieval [11][12][13], power performance assessment [14,15], wake characterization and modelling [16][17][18], controls and loads [19][20][21], and complex flows [22][23][24] to increase overall annual energy production and reduce shutdown of turbines, which demonstrates that lidars are playing an increasingly important role in wind energy, both in academia and industry.…”