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Title: Failure of Taylor's hypothesis in the atmospheric surface layer and its correction for eddy-covariance measurements

Taylors’ frozen turbulence hypothesis suggests that all turbulent eddies are advected by the mean streamwise velocity, without changes in their properties. This hypothesis has been widely invoked to compute Reynolds’ averaging using temporal turbulence data measured at a single point in space. However, in the atmospheric surface layer, the exact relationship between convection velocity and wavenumber k has not been fully revealed since previous observations were limited by either their spatial resolution or by the sampling length. Using Distributed Temperature Sensing (DTS), acquiring turbulent temperature fluctuations at high temporal and spatial frequencies, we computed convection velocities across wavenumbers using a phase spectrum method. We found that convection velocity decreases as k –1/3 at the higher wavenumbers of the inertial subrange instead of being independent of wavenumber as suggested by Taylor's hypothesis. We further corroborated this result using large eddy simulations. Applying Taylor's hypothesis thus systematically underestimates turbulent spectrum in the inertial subrange. As a result, a correction is proposed for point-based eddy-covariance measurements, which can improve surface energy budget closure and estimates of CO 2 fluxes.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ; ORCiD logo [3] ;  [2] ;  [4] ; ORCiD logo [1]
  1. Columbia Univ., New York, NY (United States)
  2. Oregon State Univ., Corvallis, OR (United States)
  3. Univ. of Oklahoma, Norman, OK (United States)
  4. Oklahoma State Univ., Stillwater, OK (United States)
Publication Date:
Grant/Contract Number:
SC0014203; SC00142013
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 9; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Columbia Univ., New York, NY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1351945
Alternate Identifier(s):
OSTI ID: 1389660

Cheng, Yu, Sayde, Chadi, Li, Qi, Basara, Jeffrey, Selker, John, Tanner, Evan, and Gentine, Pierre. Failure of Taylor's hypothesis in the atmospheric surface layer and its correction for eddy-covariance measurements. United States: N. p., Web. doi:10.1002/2017GL073499.
Cheng, Yu, Sayde, Chadi, Li, Qi, Basara, Jeffrey, Selker, John, Tanner, Evan, & Gentine, Pierre. Failure of Taylor's hypothesis in the atmospheric surface layer and its correction for eddy-covariance measurements. United States. doi:10.1002/2017GL073499.
Cheng, Yu, Sayde, Chadi, Li, Qi, Basara, Jeffrey, Selker, John, Tanner, Evan, and Gentine, Pierre. 2017. "Failure of Taylor's hypothesis in the atmospheric surface layer and its correction for eddy-covariance measurements". United States. doi:10.1002/2017GL073499. https://www.osti.gov/servlets/purl/1351945.
@article{osti_1351945,
title = {Failure of Taylor's hypothesis in the atmospheric surface layer and its correction for eddy-covariance measurements},
author = {Cheng, Yu and Sayde, Chadi and Li, Qi and Basara, Jeffrey and Selker, John and Tanner, Evan and Gentine, Pierre},
abstractNote = {Taylors’ frozen turbulence hypothesis suggests that all turbulent eddies are advected by the mean streamwise velocity, without changes in their properties. This hypothesis has been widely invoked to compute Reynolds’ averaging using temporal turbulence data measured at a single point in space. However, in the atmospheric surface layer, the exact relationship between convection velocity and wavenumber k has not been fully revealed since previous observations were limited by either their spatial resolution or by the sampling length. Using Distributed Temperature Sensing (DTS), acquiring turbulent temperature fluctuations at high temporal and spatial frequencies, we computed convection velocities across wavenumbers using a phase spectrum method. We found that convection velocity decreases as k–1/3 at the higher wavenumbers of the inertial subrange instead of being independent of wavenumber as suggested by Taylor's hypothesis. We further corroborated this result using large eddy simulations. Applying Taylor's hypothesis thus systematically underestimates turbulent spectrum in the inertial subrange. As a result, a correction is proposed for point-based eddy-covariance measurements, which can improve surface energy budget closure and estimates of CO2 fluxes.},
doi = {10.1002/2017GL073499},
journal = {Geophysical Research Letters},
number = 9,
volume = 44,
place = {United States},
year = {2017},
month = {4}
}