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- Title
Improvement of Vertical Velocity Statistics Measured by a Doppler Lidar through Comparison with Sonic Anemometer Observations.
- Authors
Bonin, Timothy A.; Newman, Jennifer F.; Klein, Petra M.; Chilson, Phillip B.; Wharton, Sonia
- Abstract
Since turbulence measurements from Doppler lidars are being increasingly used within wind energy and boundary-layer meteorology, it is important to assess and improve the accuracy of these observations. While turbulent quantities are measured by Doppler lidars in several different ways, the simplest and most frequently used statistic is vertical velocity variance (σ²ω) from zenith stares. However, the competing effects of signal noise and resolution volume limitations, which respectively increase and decrease σ²ω, reduce the accuracy of these measurements. Herein, an established method that utilizes the autocovariance of the signal to remove noise is evaluated and its skill in also correcting for volume-averaging effects in the calculation of σ²ω is assessed. Additionally, this autocovariance technique is further refined by defining the amount of lag time to use for the most accurate estimates of σ²ω. Through comparison of observations from two Doppler lidars and sonic anemometers on a 300-m tower, the autocovariance technique is shown to improve estimates of σ²ω over a variety of atmospheric conditions. After the autocoviance technique is applied, values of σ²ω from the Doppler lidars are generally in close agreement (R² & â & 0.95-0.98) with those calculated from sonic anemometer measurements.
- Subjects
DOPPLER effect; WIND power; SIGNAL-to-noise ratio
- Publication
Atmospheric Measurement Techniques Discussions, 2016, p1
- ISSN
1867-8610
- Publication type
Article
- DOI
10.5194/amt-2016-134