Coherent Doppler lidar measurements are of increasing interest for the wind energy industry. Wind measurements are fundamental inputs for the evaluation of potential energy yield and performance of wind farms. Three‐dimensional scanning Doppler lidar may provide a new basis for wind farm site selection, design and optimization. In this paper, the authors discuss Doppler lidar measurements obtained for a wind energy development. The possibility of using lidar measurements to more fully characterize the wind field is discussed, specifically terrain effects, spatial variation of winds, power density and the effect of shear at different layers within the rotor swept area. Vector retrieval methods have been applied to the lidar data, and results are presented on an elevated terrain‐following surface at hub height. The vector retrieval estimates are compared with tower measurements, after interpolation to the appropriate level. Doppler lidar data are used to estimate the spatial power density at hub height (for the period of the deployment). An example wind farm layout is presented for demonstration purposes based purely on lidar measurement, even though the lidar data acquisition period cannot be considered climatological. The strength of this approach is the ability to directly measure spatial variations of the wind field over the wind farm. Also, because Doppler lidar can measure winds at different vertical levels, an approach for estimating wind power density over the rotor swept area (rather than only the hub height) is explored. Finally, advanced vector retrieval algorithms have been applied to better characterize local wind variations and shear. Copyright © 2012 John Wiley & Sons, Ltd.

Pulsed coherent Doppler lidar systems have matured rapidly, especially at solid-state wavelengths. Turnkey systems are commercially available and are being deployed for various aviation applications. Doppler lidar data is used in the airport terminal area to map hazardous wind shear and turbulence levels and to detect and track wake vortices. Future applications could include slant path visibility monitoring. Several permanent installations and rapidly deployable instrument configurations have been achieved. The benefit of the infrared Doppler lidar relative to its microwave counterparts is the ability to sense clear air hazards, especially those in and around local terrain features. The fact that the lidar beam is quite narrow eliminates artifacts associated with sidelobe-induced ground clutter. This paper summarizes our autonomous pulsed lidar developments and reviews sample results.

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In this paper we describe the evolution of Lockheed Martin Coherent Technologies' (LMCT) 25 year WindTracer ® technology. We also present experimental results from recent ground-based measurement campaigns that demonstrate measurement accuracy in both single-and dual-Doppler configurations with a primary emphasis on wind energy applications. Results and lessons learned from a recent airborne measurement campaign for airborne wind profiling applications are also included. WindTracer ® EvolutionLMCT's WindTracer ® technology has been evolving over the past 30 years. The earliest system [1] was a research grade Doppler wind lidar employing a 10 Hz, 10 mJ, flash-lamp pumped non-eye-safe 1.06 micron wavelength Nd:YAG laser and a 20 cm aperture. This sensor first demonstrated boundary layer measurements to ranges greater than 5 km in 1988. In the early 1990's amplifiers were added in a series of steps and by 1991 the energy was increased to 1 J. This lidar system demonstrated greater than 26 km vertical wind profiles at Kennedy Space center in conjunction with a shuttle launch in the early 1991 [2].In the late 1980s, Coherent Technologies also began developing eyesafe technologies. By 1990 an eye-safe, 26 mJ, 5.7 Hz, 2.091 um, Tm,Ho:YAG lidar was developed [3]. The laser technology quickly advanced throughout the 1990s; with flashlamp pumped laser pulse energies up to 100 mJ being demonstrated, meanwhile diode pumped 10 mJ 100 Hz systems were also developed.All the earliest systems had large optical footprints and required an experienced operator, but by mid-1990 turnkey diode-pumped systems were developed for airborne operation [4,5]. By1999 very compact, diode-pumped, transceiver products called the MAG 1 and MAG-1A were developed. These 2um, 2 mJ, 500 Hz systems employed 10 cm apertures [6]. Portable 9'x8'x8' lidar shelters with full hemispherical scanners were also developed. These shelters had sufficient room inside for several operators, even though the systems could also be operated remotely or autonomously. Much of the early history through 2004 is described in greater detail in reference 5.In 2007, the wind lidar system was redesigned to take advantage of low cost telecom components, e.g., a DFB diode master oscillator. This system employs a 1.6 um Er:YAG power oscillator, producing 2.3 mJ pulses at 750 Hz with a 12.5 cm aperture. Of the diode pumped systems, this most recent WindTracer® transceiver (WTX) has demonstrated the longest measurement range (> 33 km), due to the shorter wavelength and larger aperture. In 2013, a 6'x5'x6' shelter was developed for applications requiring more compact footprints. Recently, under the AFRL Precision Air Drop program, the container is being redesigned to an even smaller footprint (4'x3.5'x3') with a predicted total weight below 700 lbs. Both compact systems employ the standard WTX sensor. WindTracer ® Validation ExperimentsRecently, LMCT has conducted two research programs demonstrating WindTracer ® measurement accuracy in both single-and dual-Doppler wind vector retrieva...