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Title: Validating precision estimates in horizontal wind measurements from a Doppler lidar

Abstract

Results from a recent field campaign are used to assess the accuracy of wind speed and direction precision estimates produced by a Doppler lidar wind retrieval algorithm. The algorithm, which is based on the traditional velocity-azimuth-display (VAD) technique, estimates the wind speed and direction measurement precision using standard error propagation techniques, assuming the input data (i.e., radial velocities) to be contaminated by random, zero-mean, errors. For this study, the lidar was configured to execute an 8-beam plan-position-indicator (PPI) scan once every 12 min during the 6-week deployment period. Several wind retrieval trials were conducted using different schemes for estimating the precision in the radial velocity measurements. Here, the resulting wind speed and direction precision estimates were compared to differences in wind speed and direction between the VAD algorithm and sonic anemometer measurements taken on a nearby 300 m tower.

Authors:
 [1];  [2];  [2];  [3];  [4]; ORCiD logo [5]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.
  3. National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Cooperative Institute for Research in Environmental Sciences, Boulder, CO (United States)
  4. National Center for Atmospheric Research, Boulder, CO (United States)
  5. Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1353004
Report Number(s):
NREL/JA-5000-68401
Journal ID: ISSN 1867-8548
Grant/Contract Number:
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Atmospheric Measurement Techniques (Online)
Additional Journal Information:
Journal Name: Atmospheric Measurement Techniques (Online); Journal Volume: 10; Journal Issue: 3; Journal ID: ISSN 1867-8548
Publisher:
European Geosciences Union
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; 47 OTHER INSTRUMENTATION; doppler lidar; wind speed; direction measurement

Citation Formats

Newsom, Rob K., Brewer, W. Alan, Wilczak, James M., Wolfe, Daniel E., Oncley, Steven P., and Lundquist, Julie K. Validating precision estimates in horizontal wind measurements from a Doppler lidar. United States: N. p., 2017. Web. doi:10.5194/amt-10-1229-2017.
Newsom, Rob K., Brewer, W. Alan, Wilczak, James M., Wolfe, Daniel E., Oncley, Steven P., & Lundquist, Julie K. Validating precision estimates in horizontal wind measurements from a Doppler lidar. United States. doi:10.5194/amt-10-1229-2017.
Newsom, Rob K., Brewer, W. Alan, Wilczak, James M., Wolfe, Daniel E., Oncley, Steven P., and Lundquist, Julie K. Thu . "Validating precision estimates in horizontal wind measurements from a Doppler lidar". United States. doi:10.5194/amt-10-1229-2017. https://www.osti.gov/servlets/purl/1353004.
@article{osti_1353004,
title = {Validating precision estimates in horizontal wind measurements from a Doppler lidar},
author = {Newsom, Rob K. and Brewer, W. Alan and Wilczak, James M. and Wolfe, Daniel E. and Oncley, Steven P. and Lundquist, Julie K.},
abstractNote = {Results from a recent field campaign are used to assess the accuracy of wind speed and direction precision estimates produced by a Doppler lidar wind retrieval algorithm. The algorithm, which is based on the traditional velocity-azimuth-display (VAD) technique, estimates the wind speed and direction measurement precision using standard error propagation techniques, assuming the input data (i.e., radial velocities) to be contaminated by random, zero-mean, errors. For this study, the lidar was configured to execute an 8-beam plan-position-indicator (PPI) scan once every 12 min during the 6-week deployment period. Several wind retrieval trials were conducted using different schemes for estimating the precision in the radial velocity measurements. Here, the resulting wind speed and direction precision estimates were compared to differences in wind speed and direction between the VAD algorithm and sonic anemometer measurements taken on a nearby 300 m tower.},
doi = {10.5194/amt-10-1229-2017},
journal = {Atmospheric Measurement Techniques (Online)},
number = 3,
volume = 10,
place = {United States},
year = {Thu Mar 30 00:00:00 EDT 2017},
month = {Thu Mar 30 00:00:00 EDT 2017}
}

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  • When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of itsmore » high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. Moreover, the radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.« less
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