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Title: Improvement of vertical velocity statistics measured by a Doppler lidar through comparison with sonic anemometer observations

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 ( w' 2) from zenith stares. But, the competing effects of signal noise and resolution volume limitations, which respectively increase and decrease w' 2, reduce the accuracy of these measurements. Herein, an established method that utilises the autocovariance of the signal to remove noise is evaluated and its skill in correcting for volume-averaging effects in the calculation of w' 2 is also assessed. In addition, this autocovariance technique is further refined by defining the amount of lag time to use for the most accurate estimates of w' 2. And through comparison of observations from two Doppler lidars and sonic anemometers on a 300 m tower, the autocovariance technique is shown to generally improve estimates of w' 2. After the autocovariance technique is applied, values of w' 2 from the Doppler lidars are generally in close agreement ( R 2 ≈ 0.95 -0.98) with those calculated from sonic anemometer measurements.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of Oklahoma, Norman, OK (United States). School of Meteorology
  2. Univ. of Oklahoma, Norman, OK (United States). School of Meteorology, Cooperative Inst. for Mesoscale Meteorological Studies
  3. Univ. of Oklahoma, Norman, OK (United States). School of Meteorology, Advanced Radar Research Center and School of Meteorology
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Atmospheric Measurement Techniques (Online)
Additional Journal Information:
Journal Name: Atmospheric Measurement Techniques (Online); Journal Volume: 9; Journal Issue: 12; Journal ID: ISSN 1867-8548
Publisher:
European Geosciences Union
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1395316