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

Mauder, Matthias; Eggert, Michael; Gutsmuths, Christian; Oertel, Stefan; Wilhelm, Paul; Voelksch, Ingo; Wanner, Luise; Tambke, Jens; Bogoev, Ivan

doi:https://doi.org/10.5194/amt-13-969-2020

Articles | Volume 13, issue 2

https://doi.org/10.5194/amt-13-969-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-13-969-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 2

Research article

|

02 Mar 2020

Research article |

| 02 Mar 2020

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

Matthias Mauder, Michael Eggert, Christian Gutsmuths, Stefan Oertel, Paul Wilhelm, Ingo Voelksch, Luise Wanner, Jens Tambke, and Ivan Bogoev

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Final revised paper (published on 02 Mar 2020)
Preprint (discussion started on 06 May 2019)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Comments in pdf file', Anonymous Referee #2, 03 Jun 2019
- AC1: 'Final response to RC1', Matthias Mauder, 26 Jul 2019
RC2: 'Review of Mauder et al.,', John Frank, 04 Jun 2019
- AC2: 'Final response to RC2', Matthias Mauder, 26 Jul 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Matthias Mauder on behalf of the Authors (31 Jul 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (01 Aug 2019) by Szymon Malinowski

RR by Anonymous Referee #2 (16 Aug 2019)

RR by John Frank (20 Aug 2019)

Suggestions for revision or reasons for rejection

I have read the author’s comments to both reviewers and the revised manuscript and believe that this paper is acceptable for publication after the consideration of one minor comment:

In the revised manuscript on page 3, line 25-27, a new sentence has been added that states “This is important because horizontal wind velocities are usually much larger than vertical wind velocities, and a distorted measurement of the horizontal wind speed directly affects the vertical wind speed measurement”. This statement is vague and could be misinterpreted.

In the context of this paragraph, this statement is probably meant to explain the advantages of the non-orthogonal CSAT3 versus previous anemometers that were orthogonal. Yet, for an orthogonal anemometer, this statement could be inaccurate because the horizontal and vertical measurements are entirely independent. It could be argued that flow distortions due to the horizontal transducers/structure might fundamentally distort the wind flow in all dimensions such that the vertical component is fundamentally changed, leading to an accurate measurement of a distorted vertical wind component. I’m not sure if this has ever been proven or disproven. Regardless, for an orthogonal anemometer, it is not clear that there is any correlation between horizontal and vertical measurement errors.

Regarding a non-orthogonal anemometer, it is important to note that all measurement errors originate in the transducer measurements. This means that while a distorted horizontal measurement will directly affect the transducer measurements, it might not affect the vertical wind speed measurement. This would occur if the measurement error only affects the horizontal components of the transducer measurements. In this case, while the transducers measurements would be affected, the vertical wind measurement (which is proportional to the sum of the three transducer measurements in a non-orthogonal anemometer) could still be unaffected.

I would ask the authors to consider revising this sentence.

Otherwise, well done.
John Frank

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ED: Publish subject to minor revisions (review by editor) (20 Aug 2019) by Szymon Malinowski

AR by Matthias Mauder on behalf of the Authors (13 Sep 2019) Author's response Manuscript

ED: Publish as is (28 Jan 2020) by Szymon Malinowski

AR by Matthias Mauder on behalf of the Authors (29 Jan 2020)

Short summary

Sonic anemometers are prone to probe-induced flow distortion effects. 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 flow distortion. Our results show an agreement of the mean wind velocity measurements and the standard deviations of the vertical wind speed with comparabilities of 0.082 and 0.020 m s⁻¹, respectively. Friction velocity is underestimated by the CSAT3B by 3 %.