Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity
Parameterisation of the air-sea gas transfer velocity of CO2 and other trace gases under open-ocean conditions has been a focus of air-sea interaction research and is required for accurately determining ocean carbon uptake. Ships are the most widely used platform for air-sea flux measurements but th...
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ftnuigalway:oai:https://researchrepository.universityofgalway.ie:10379/12370 2024-09-30T14:44:08+00:00 Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity Landwehr, Sebastian Miller, Scott D. Smith, Murray J. Bell, Thomas G. Saltzman, Eric S. Ward, Brian 2018-03-28 http://hdl.handle.net/10379/12370 https://doi.org/10.13025/27441 https://doi.org/10.5194/acp-18-4297-2018 unknown Copernicus GmbH Atmospheric Chemistry and Physics Landwehr, Sebastian; Miller, Scott D. Smith, Murray J.; Bell, Thomas G.; Saltzman, Eric S.; Ward, Brian (2018). Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity. Atmospheric Chemistry and Physics 18 (6), 4297-4315 1680-7324 http://hdl.handle.net/10379/12370 https://doi.org/10.13025/27441 doi:10.5194/acp-18-4297-2018 Attribution-NonCommercial-NoDerivs 3.0 Ireland https://creativecommons.org/licenses/by-nc-nd/3.0/ie/ gas transfer velocity flux measurements flow distortion mobile platforms surface-layer water-vapor wind-speed open-ocean turbulence momentum Article 2018 ftnuigalway https://doi.org/10.13025/2744110.5194/acp-18-4297-2018 2024-09-17T14:44:29Z Parameterisation of the air-sea gas transfer velocity of CO2 and other trace gases under open-ocean conditions has been a focus of air-sea interaction research and is required for accurately determining ocean carbon uptake. Ships are the most widely used platform for air-sea flux measurements but the quality of the data can be compromised by airflow distortion and sensor cross-sensitivity effects. Recent improvements in the understanding of these effects have led to enhanced corrections to the shipboard eddy covariance (EC) measurements. Here, we present a revised analysis of eddy covariance measurements of air-sea CO2 and momentum fluxes from the Southern Ocean Surface Ocean Aerosol Production (SOAP) study. We show that it is possible to significantly reduce the scatter in the EC data and achieve consistency between measurements taken on station and with the ship underway. The gas transfer velocities from the EC measurements correlate better with the EC friction velocity (u(*)) than with mean wind speeds derived from shipboard measurements corrected with an airflow distortion model. For the observed range of wind speeds (u (10) (N) = 3-23 m s(-1)), the transfer velocities can be parameterised with a linear fit to u(*). The SOAP data are compared to previous gas transfer parameterisations using u (10) (N) computed from the EC friction velocity with the drag coefficient from the Coupled Ocean-Atmosphere Response Experiment (COARE) model version 3.5. The SOAP results are consistent with previous gas transfer studies, but at high wind speeds they do not support the sharp increase in gas transfer associated with bubble-mediated transfer predicted by physically based models. Article in Journal/Newspaper Southern Ocean National University of Ireland (NUI), Galway: ARAN Southern Ocean |
institution |
Open Polar |
collection |
National University of Ireland (NUI), Galway: ARAN |
op_collection_id |
ftnuigalway |
language |
unknown |
topic |
gas transfer velocity flux measurements flow distortion mobile platforms surface-layer water-vapor wind-speed open-ocean turbulence momentum |
spellingShingle |
gas transfer velocity flux measurements flow distortion mobile platforms surface-layer water-vapor wind-speed open-ocean turbulence momentum Landwehr, Sebastian Miller, Scott D. Smith, Murray J. Bell, Thomas G. Saltzman, Eric S. Ward, Brian Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
topic_facet |
gas transfer velocity flux measurements flow distortion mobile platforms surface-layer water-vapor wind-speed open-ocean turbulence momentum |
description |
Parameterisation of the air-sea gas transfer velocity of CO2 and other trace gases under open-ocean conditions has been a focus of air-sea interaction research and is required for accurately determining ocean carbon uptake. Ships are the most widely used platform for air-sea flux measurements but the quality of the data can be compromised by airflow distortion and sensor cross-sensitivity effects. Recent improvements in the understanding of these effects have led to enhanced corrections to the shipboard eddy covariance (EC) measurements. Here, we present a revised analysis of eddy covariance measurements of air-sea CO2 and momentum fluxes from the Southern Ocean Surface Ocean Aerosol Production (SOAP) study. We show that it is possible to significantly reduce the scatter in the EC data and achieve consistency between measurements taken on station and with the ship underway. The gas transfer velocities from the EC measurements correlate better with the EC friction velocity (u(*)) than with mean wind speeds derived from shipboard measurements corrected with an airflow distortion model. For the observed range of wind speeds (u (10) (N) = 3-23 m s(-1)), the transfer velocities can be parameterised with a linear fit to u(*). The SOAP data are compared to previous gas transfer parameterisations using u (10) (N) computed from the EC friction velocity with the drag coefficient from the Coupled Ocean-Atmosphere Response Experiment (COARE) model version 3.5. The SOAP results are consistent with previous gas transfer studies, but at high wind speeds they do not support the sharp increase in gas transfer associated with bubble-mediated transfer predicted by physically based models. |
format |
Article in Journal/Newspaper |
author |
Landwehr, Sebastian Miller, Scott D. Smith, Murray J. Bell, Thomas G. Saltzman, Eric S. Ward, Brian |
author_facet |
Landwehr, Sebastian Miller, Scott D. Smith, Murray J. Bell, Thomas G. Saltzman, Eric S. Ward, Brian |
author_sort |
Landwehr, Sebastian |
title |
Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
title_short |
Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
title_full |
Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
title_fullStr |
Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
title_full_unstemmed |
Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
title_sort |
using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity |
publisher |
Copernicus GmbH |
publishDate |
2018 |
url |
http://hdl.handle.net/10379/12370 https://doi.org/10.13025/27441 https://doi.org/10.5194/acp-18-4297-2018 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Atmospheric Chemistry and Physics Landwehr, Sebastian; Miller, Scott D. Smith, Murray J.; Bell, Thomas G.; Saltzman, Eric S.; Ward, Brian (2018). Using eddy covariance to measure the dependence of air–sea co 2 exchange rate on friction velocity. Atmospheric Chemistry and Physics 18 (6), 4297-4315 1680-7324 http://hdl.handle.net/10379/12370 https://doi.org/10.13025/27441 doi:10.5194/acp-18-4297-2018 |
op_rights |
Attribution-NonCommercial-NoDerivs 3.0 Ireland https://creativecommons.org/licenses/by-nc-nd/3.0/ie/ |
op_doi |
https://doi.org/10.13025/2744110.5194/acp-18-4297-2018 |
_version_ |
1811645609860399104 |