Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank

A comparative study of simultaneous heat and gas exchange measurements was performed in the large annular Heidelberg Air–Sea Interaction Facility, the Aeolotron, under homogeneous water surface conditions. The use of two gas tracers, N<sub>2</sub>O and C<sub>2</sub>HF<sub&...

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Main Authors: L. Nagel, K. E. Krall, B. Jähne
Format: Article
Language:English
Published: Copernicus Publications 2015-01-01
Series:Ocean Science
Online Access:http://www.ocean-sci.net/11/111/2015/os-11-111-2015.pdf
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spelling doaj-c06ef37b81ce4c4c9789408ae0efd7372020-11-25T01:42:29ZengCopernicus PublicationsOcean Science1812-07841812-07922015-01-0111111112010.5194/os-11-111-2015Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tankL. Nagel0K. E. Krall1B. Jähne2Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, GermanyInstitute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, GermanyInstitute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, GermanyA comparative study of simultaneous heat and gas exchange measurements was performed in the large annular Heidelberg Air–Sea Interaction Facility, the Aeolotron, under homogeneous water surface conditions. The use of two gas tracers, N<sub>2</sub>O and C<sub>2</sub>HF<sub>5</sub>, resulted not only in gas transfer velocities, but also in the measurement of the Schmidt number exponent n with a precision of ±0.025. The original controlled flux, or active thermographic, technique proposed by Jähne et al. (1989) was applied by heating a large patch at the water surface to measure heat transfer velocities. Heating a large patch, the active thermography technique is laterally homogeneous, and problems of lateral transport effects are avoided. Using the measured Schmidt number exponents, the ratio of the scaled heat transfer velocities to the measured gas transfer velocities is 1.046 ± 0.040, a good agreement within the limits of experimental uncertainties. This indicates the possibility to scale heat transfer velocities measured by active thermography to gas transfer velocities, provided that the Schmidt number exponent is known and that the heated patch is large enough to reach the thermal equilibrium.http://www.ocean-sci.net/11/111/2015/os-11-111-2015.pdf
collection DOAJ
language English
format Article
sources DOAJ
author L. Nagel
K. E. Krall
B. Jähne
spellingShingle L. Nagel
K. E. Krall
B. Jähne
Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
Ocean Science
author_facet L. Nagel
K. E. Krall
B. Jähne
author_sort L. Nagel
title Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
title_short Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
title_full Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
title_fullStr Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
title_full_unstemmed Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
title_sort comparative heat and gas exchange measurements in the heidelberg aeolotron, a large annular wind-wave tank
publisher Copernicus Publications
series Ocean Science
issn 1812-0784
1812-0792
publishDate 2015-01-01
description A comparative study of simultaneous heat and gas exchange measurements was performed in the large annular Heidelberg Air–Sea Interaction Facility, the Aeolotron, under homogeneous water surface conditions. The use of two gas tracers, N<sub>2</sub>O and C<sub>2</sub>HF<sub>5</sub>, resulted not only in gas transfer velocities, but also in the measurement of the Schmidt number exponent n with a precision of ±0.025. The original controlled flux, or active thermographic, technique proposed by Jähne et al. (1989) was applied by heating a large patch at the water surface to measure heat transfer velocities. Heating a large patch, the active thermography technique is laterally homogeneous, and problems of lateral transport effects are avoided. Using the measured Schmidt number exponents, the ratio of the scaled heat transfer velocities to the measured gas transfer velocities is 1.046 ± 0.040, a good agreement within the limits of experimental uncertainties. This indicates the possibility to scale heat transfer velocities measured by active thermography to gas transfer velocities, provided that the Schmidt number exponent is known and that the heated patch is large enough to reach the thermal equilibrium.
url http://www.ocean-sci.net/11/111/2015/os-11-111-2015.pdf
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