Validation of three-component wind lidar sensor for traceable highly resolved wind vector measurements

Oertel, Stefan; Eggert, Michael; Gutsmuths, Christian; Wilhelm, Paul; Müller, H.; Többen, Helmut

doi:10.5194/jsss-8-9-2019

Cited by 12 publications

(10 citation statements)

References 11 publications

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“…The major drawback of synchronized multi-LiDAR measurements is the low availability of data due to blockage (e.g., the available data from dual LiDARs scanning ridges was 50-70% [175]). Recently, new LiDAR systems with three spatially separated emitters [176] or with three receiving units [177] have been developed to measure 3D wind vector with high spatial and temporal resolutions. These systems show considerable potentials for conducting wind measurements in complex terrain, as well as for gust detection where high temporal resolution is desired.…”

Section: Discussionmentioning

confidence: 99%

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

et al. 2019

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Doppler wind LiDAR (Light Detection And Ranging) makes use of the principle of optical Doppler shift between the reference and backscattered radiations to measure radial velocities at distances up to several kilometers above the ground. Such instruments promise some advantages, including its large scan volume, movability and provision of 3-dimensional wind measurements, as well as its relatively higher temporal and spatial resolution comparing with other measurement devices. In recent decades, Doppler LiDARs developed by scientific institutes and commercial companies have been well adopted in several real-life applications. Doppler LiDARs are installed in about a dozen airports to study aircraft-induced vortices and detect wind shears. In the wind energy industry, the Doppler LiDAR technique provides a promising alternative to in-situ techniques in wind energy assessment, turbine wake analysis and turbine control. Doppler LiDARs have also been applied in meteorological studies, such as observing boundary layers and tracking tropical cyclones. These applications demonstrate the capability of Doppler LiDARs for measuring backscatter coefficients and wind profiles. In addition, Doppler LiDAR measurements show considerable potential for validating and improving numerical models. It is expected that future development of the Doppler LiDAR technique and data processing algorithms will provide accurate measurements with high spatial and temporal resolutions under different environmental conditions.

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Section: Discussionmentioning

confidence: 99%

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

et al. 2019

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“…The most widely used wind remote sensing devices are conventional monostatic Doppler lidar systems that have been established in wind energy applications in recent years (e.g. Pearson et al, 2009). Such systems utilize a common transmitting and receiving beam that measures the wind velocity component in beam direction via a Doppler shift of the received scattering light from aerosols travelling along the path of the transmitting laser beam (Drain, 1980).…”

Section: Bistatic Doppler Lidarmentioning

confidence: 99%

“…As a reference instrument, we employ a high-resolution bistatic Doppler lidar, which has been developed at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany (Oertel et al, 2019). This optical remote sensing device is naturally free of any flow distortion errors and determines the 3D wind vector in a volume of less than 0.0005 m 3 , for measurement heights up to 200 m at an output frequency of up to 10 s −1 , which is comparable to the sampling characteristics of a typical sonic anemometer.…”

Section: Introductionmentioning

confidence: 99%

Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar

et al. 2020

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Abstract. Accurate measurements of turbulence statistics in the atmosphere are important for eddy-covariance measurements, wind energy research, and the validation of atmospheric numerical models. Sonic anemometers are widely used for these applications. However, these instruments are prone to probe-induced flow distortion effects, and the magnitude of the resulting errors has been debated due to the lack of an absolute reference instrument under field conditions. Here, we present the results of an intercomparison experiment between a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar, which is inherently free of any flow distortion. This novel remote sensing instrument has otherwise very similar spatial and temporal sampling characteristics to the sonic anemometer and hence served as a reference for this comparison. The presented measurements were carried out over flat homogeneous terrain at a measurement height of 30 m. We provide a comparative statistical analysis of the resulting mean wind velocities, the standard deviations of the vertical wind speed and the friction velocity and investigate the reasons for the observed deviations based on the turbulence spectra and co-spectra. Our results show an agreement of the mean wind velocity measurements and the standard deviations of the vertical wind speed with a comparability of 0.082 and 0.020 m s−1, respectively. Biases for these two quantities were 0.003 and 0.012 m s−1, respectively. Slightly larger differences were observed for friction velocity. Analysis of the corresponding co-spectra showed that the CSAT3B underestimates this quantity systematically by about 3 % on average as a result of co-spectral losses in the frequency range between 0.1 and 5 s−1. We also found that an angle-of-attack-dependent transducer-shadowing correction does not improve the agreement between the CSAT3B and the Physikalisch-Technische Bundesanstalt (PTB) lidar effectively.

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“…The novel three-component lidar system developed by the PTB is aimed to overcome the present limitation to almost homogeneous wind fields given by the monostatic working principle (Oertel et al, 2019). The basic idea of this system relies on utilizing a bistatic measurement setup (Harris et al, 2001), i.e.…”

Section: Bistatic Doppler Lidarmentioning

confidence: 99%

“…Further problems of past studies are the influence of shadowing between adjacent sensors and support structures, lack of homogenous flat terrain, and the uncertainty of the coordinate rotations. As a reference instrument, we employ a highresolution bistatic Doppler lidar, which has been developed at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany (Oertel et al, 2019). This optical remote sensing device is naturally free of any flow-distortion errors Atmos.…”

mentioning

confidence: 99%

Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar

Mauder¹,

Eggert²,

Gutsmuths³

et al. 2019

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Accurate measurements of turbulence statistics in the atmosphere are important for eddy-covariance measurements, wind energy research, and the validation of atmospheric numerical models. Sonic anemometers are widely used for these applications. However, these instruments are prone to probe-induced flow distortion effects, and the magnitude of the resulting errors has been debated due to the lack of an absolute reference instrument under field conditions. Here, we present the results of an intercomparison experiment between a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar, which 15 is inherently free of any flow-distortion. This novel remote sensing instrument has otherwise very similar spatial and temporal sampling characteristics as the sonic anemometer and hence served as a reference for this comparison. The presented measurements were carried out over flat homogeneous terrain, at a measurement height of 30 m. We provide a comparative statistical analysis of the resulting mean wind velocities, the standard deviations of the vertical wind speed and the friction velocity and investigate the reasons for the observed deviations based on the turbulence spectra and cospectra. Our results 20 show a very good agreement of the mean wind velocity measurements and the standard deviations of the vertical wind speed, with comparabilities of 0.082 and 0.017 m s −1 , respectively. Biases for these two quantities were very low, being smaller than 0.01 m s −1 , which corresponds to about 1 % in relative terms. Slightly larger differences were observed for friction velocity.Analysis of the corresponding cospectra showed that the CSAT3B underestimates this quantity systematically by about 3 % on average as a result of too steep a drop-off in the inertial sub-range. We also found that an angle-of-attack dependent 25 transducer-shadowing correction does not improve this agreement effectively because it leads to an artificial correlation between the three wind components and therefore severely distorts the shape of the cospectra.

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Validation of three-component wind lidar sensor for traceable highly resolved wind vector measurements

Cited by 12 publications

References 11 publications

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar

Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar

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