Motion-correlated flow distortion and wave-induced biases in air–sea flux measurements from ships
Motion-correlated flow distortion and wave-induced biases in air–sea flux measurements from ships
Direct measurements of the turbulent air–sea fluxes of momentum, heat, moisture and gases are often made using sensors mounted on ships. Ship-based turbulent wind measurements are corrected for platform motion using well established techniques, but biases at scales associated with wave and platform motion are often still apparent in the flux measurements. It has been uncertain whether this signal is due to time-varying distortion of the air flow over the platform or to wind–wave interactions impacting the turbulence. Methods for removing such motion-scale biases from scalar measurements have previously been published but their application to momentum flux measurements remains controversial. Here we show that the measured motion-scale bias has a dependence on the horizontal ship velocity and that a correction for it reduces the dependence of the measured momentum flux on the orientation of the ship to the wind. We conclude that the bias is due to experimental error and that time-varying motion-dependent flow distortion is the likely source.
10619-10629
Prytherch, J.
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Yelland, M.J.
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Brooks, I.M.
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Tupman, D.J.
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Moat, B.I.
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Norris, S.J.
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25 September 2015
Prytherch, J.
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Yelland, M.J.
3b2e2a38-334f-430f-b110-253a0a835a07
Brooks, I.M.
e1e4e3cb-8165-40f2-900b-81ff12bc1de2
Tupman, D.J.
d7a2cae6-b32a-404d-8bce-9be3ea6598f1
Moat, B.I.
497dbb18-a98f-466b-b459-aa2c872ad2dc
Norris, S.J.
f97ad34b-2db3-4a7b-8b88-58b51fbd9a9c
Prytherch, J., Yelland, M.J., Brooks, I.M., Tupman, D.J., Moat, B.I. and Norris, S.J.
(2015)
Motion-correlated flow distortion and wave-induced biases in air–sea flux measurements from ships.
Atmospheric Chemistry and Physics, 15 (18), .
(doi:10.5194/acp-15-10619-2015).
Abstract
Direct measurements of the turbulent air–sea fluxes of momentum, heat, moisture and gases are often made using sensors mounted on ships. Ship-based turbulent wind measurements are corrected for platform motion using well established techniques, but biases at scales associated with wave and platform motion are often still apparent in the flux measurements. It has been uncertain whether this signal is due to time-varying distortion of the air flow over the platform or to wind–wave interactions impacting the turbulence. Methods for removing such motion-scale biases from scalar measurements have previously been published but their application to momentum flux measurements remains controversial. Here we show that the measured motion-scale bias has a dependence on the horizontal ship velocity and that a correction for it reduces the dependence of the measured momentum flux on the orientation of the ship to the wind. We conclude that the bias is due to experimental error and that time-varying motion-dependent flow distortion is the likely source.
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Published date: 25 September 2015
Organisations:
Ocean Technology and Engineering, Marine Physics and Ocean Climate
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Local EPrints ID: 382060
URI: http://eprints.soton.ac.uk/id/eprint/382060
PURE UUID: f3215809-3087-4c43-b49d-e684b92e9f8c
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Date deposited: 29 Sep 2015 13:37
Last modified: 14 Mar 2024 21:25
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Contributors
Author:
J. Prytherch
Author:
M.J. Yelland
Author:
I.M. Brooks
Author:
D.J. Tupman
Author:
B.I. Moat
Author:
S.J. Norris
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