A method to assess the accuracy of sonic anemometer measurements

• Main Authors: A. Peña, E. Dellwik, J. Mann
• Format: Article
• Language: English
• Published: Copernicus Publications 2019-01-01
• Series: Atmospheric Measurement Techniques
• Online Access: https://www.atmos-meas-tech.net/12/237/2019/amt-12-237-2019.pdf

<p>We propose a method to assess the accuracy of atmospheric turbulence measurements performed by sonic anemometers and test it by analysis of measurements from two commonly used sonic anemometers, a Metek USA-1 and a Campbell CSAT3, at two locations in Denmark. The method relies on the estimation of the ratio of the vertical to the along-wind velocity power spectrum within the inertial subrange and does not require the use of another measurement as reference. When we correct the USA-1 to account for three-dimensional flow-distortion effects, as recommended by Metek GmbH, the ratio is very close to <span class="inline-formula">4∕3</span> as expected from Kolmogorov's hypothesis, whereas non-corrected data show a ratio close to 1. For the CSAT3, non-corrected data show a ratio close to 1.1 for the two sites and for wind directions where the instrument is not directly affected by the mast. After applying a previously suggested flow-distortion correction, the ratio increases up to <span class="inline-formula">≈1.2</span>, implying that the effect of flow distortion in this instrument is still not properly accounted for.</p>