scholarly journals A novel wave breaking framework to estimate air-sea gas transfer velocities

2021 ◽  
Author(s):  
Sophia E. Brumer ◽  
Christopher J Zappa
Keyword(s):  
Wave Breaking ◽  
Gas Transfer

scholarly journals First air–sea gas exchange laboratory study at hurricane wind speeds

2013 ◽  
Vol 10 (6) ◽  
pp. 1971-1996
Author(s):  
K. E. Krall ◽  
B. Jähne
Keyword(s):  
Wave Breaking ◽  
High Speed ◽  
Wind Wave ◽  
Breaking Waves ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Wind Speeds ◽  
Hurricane Wind ◽  
Wide Range ◽  
Enhanced Surface

Abstract. In a pilot study conducted in October and November 2011, air–sea gas transfer velocities of the two sparingly soluble trace gases hexafluorobenzene and 1,4-difluorobenzene were measured in the unique High-Speed Wind-Wave Tank at Kyoto University, Japan. This air–sea interaction facility is capable of producing hurricane strength wind speeds of up to u10=67 m s−1. This constitutes the first lab study of gas transfer at such high wind speeds. The measured transfer velocities k600 spanned two orders of magnitude, lying between 11 cm h−1 and 1180 cm h−1 with the latter being the highest ever measured wind induced gas transfer velocity. The measured gas transfer velocities are in agreement with the only available dataset at hurricane wind speeds (McNeil and D'Asaro, 2007). The disproportionately large increase of the transfer velocities found at highest wind speeds indicates a new regime of air–sea gas transfer, which is characterized by strong wave breaking, enhanced turbulence and bubble cloud entrainment. It was found that tracers spanning a wide range of solubilities and diffusivities are needed to separate the effects of enhanced surface area and turbulence due to breaking waves from the effects of bubble and spray mediated gas transfer.

scholarly journals First laboratory study of air–sea gas exchange at hurricane wind speeds

Ocean Science ◽  
2014 ◽  
Vol 10 (2) ◽  
pp. 257-265 ◽  
Author(s):  
K. E. Krall ◽  
B. Jähne
Keyword(s):  
Wave Breaking ◽  
High Speed ◽  
Wind Wave ◽  
Gas Transfer ◽  
High Wind ◽  
Transfer Velocity ◽  
Data Set ◽  
Wind Speeds ◽  
Bubble Cloud ◽  
Hurricane Wind

Abstract. In a pilot study conducted in October and November 2011, air–sea gas transfer velocities of the two sparingly soluble trace gases hexafluorobenzene and 1,4-difluorobenzene were measured in the unique high-speed wind-wave tank at Kyoto University, Japan. This air–sea interaction facility is capable of producing hurricane strength wind speeds of up to u10 =67 m s−1. This constitutes the first lab study of gas transfer at such high wind speeds. The measured transfer velocities k600 spanned two orders of magnitude, lying between 11 cm h−1 and 1180 cm h−1 with the latter being the highest ever measured wind-induced gas transfer velocity. The measured gas transfer velocities are in agreement with the only available data set at hurricane wind speeds (McNeil and D'Asaro, 2007). The disproportionately large increase of the transfer velocities found at highest wind speeds indicates a new regime of air–sea gas transfer, which is characterized by strong wave breaking, enhanced turbulence and bubble cloud entrainment.

scholarly journals Gas transfer velocity in the presence of wave breaking

Tellus B ◽  
2016 ◽  
Vol 68 (1) ◽  
pp. 27034 ◽  
Author(s):  
Li Shuiqing ◽  
Zhao Dongliang
Keyword(s):  
Wave Breaking ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Gas Transfer Velocity

Effect of Microscale Wave Breaking on Air-Water Gas Transfer

2013 ◽  
pp. 23-29 ◽  
Author(s):  
C. J. Zappal ◽  
W. E. Asher ◽  
A. T. Jessup ◽  
J. Klinke ◽  
S. R. Long
Keyword(s):  
Wave Breaking ◽  
Gas Transfer ◽  
Water Gas

New parameterizations of air-sea CO2 gas transfer velocity on wave breaking

2021 ◽  
Author(s):  
Shuo Li ◽  
Alexander Babanin
Keyword(s):  
Wind Speed ◽  
Wave Breaking ◽  
Global Ocean ◽  
Gas Transfer ◽  
Data Sets ◽  
Orbital Velocity ◽  
Transfer Velocity ◽  
Gas Transfer Velocity ◽  
Wave Parameters ◽  
Transfer Models

<p>Ocean surface waves and wave breaking play a pivotal role in air-sea Carbon Dioxide (<em>CO<sub>2</sub></em>) gas exchange by producing abundant turbulence and bubbles. Contemporary gas transfer models are generally implemented with wind speed, rather than wave parameters, to quantify <em>CO<sub>2</sub></em> transfer velocity (<em>K<sub>CO2</sub></em>). In our work, the direct relationship of <em>K<sub>CO2</sub></em> and waves is explored through the combination of laboratory experiment, field observational data and estimation of global ocean uptake of <em>CO<sub>2</sub></em>.</p><p>In laboratory, the waves and <em>CO<sub>2 </sub></em>transfer at water surface are forced for simultaneous measurements in a wind-wave flume. Three types of waves are exercised: mechanically generated monochromatic waves, pure wind waves with 10-meter wind speed ranging from 4.5 <em>m/s</em> to 15.5 <em>m/s</em>, and the coupling of monochromatic waves with superimposed wind force. The results show that <em>K<sub>CO2 </sub></em>is well correlated with wave height and orbital velocity. In the connection of <em>K<sub>CO2 </sub></em>with breakers, wave breaking probability (<em>b<sub>T</sub></em>) should also be considered. The wind speed is competent too in describing <em>K<sub>CO2 </sub></em>but may be inadequate for varied wave ages. A non-dimensional formula (hereafter the RHM model) is proposed in which gas transfer velocity is expressed as a main function of wave Reynolds number (<em>R<sub>HM </sub>= U<sub>w</sub>H<sub>s</sub>/ν<sub>w</sub></em>, where <em>U<sub>w</sub></em> is wave orbital velocity, <em>H<sub>s</sub></em> is significant wave height, <em>ν<sub>w</sub></em> is viscosity of water) while wind is accounted as an enhancement factor (<em>1+Û</em>, where <em>Û </em>is non-dimensional wind speed denoting the reverse of wave age). For wave breaking dominated gas exchange, second formula (hereafter the BT model) is developed by replacing components of <em>R<sub>HM </sub></em>with breaker’s statistics and integrates an additional factor of <em>b<sub>T. </sub></em></p><p>Utilizing campaign observations from open ocean, the RHM model can effectively reconcile the laboratory and field data sets. The BT model related with wave breaking, on the other hand, is adapted by including a complementary term of bubble-mediated gas transfer in which the bubble injection rate is parameterized with <em>R<sub>HM</sub></em>. The updated BT model also performs well for the data. The conventional wind-based models show similar features as in laboratory experiments: the wind speed successfully captures the variation of gas transfer for respective observation yet is insufficient to neutralize the gaps among data sets.</p><p>Our wave-based gas transfer models are applied for the estimation of net annual <em>CO<sub>2</sub></em> fluxes of global ocean in the period of year 1985-2017. The results are in high agreement with previous studies. The wind-based gas transfer models might underestimate the <em>CO<sub>2</sub></em> fluxes although the estimations still distribute within the range of uncertainty. Moreover, the models using wave parameters are found advantageous over the wind-based models in reducing the uncertainties of gas fluxes.</p>

scholarly journals Microscale wave breaking and air-water gas transfer

2001 ◽  
Vol 106 (C5) ◽  
pp. 9385-9391 ◽  
Author(s):  
C. J. Zappa ◽  
W. E. Asher ◽  
A. T. Jessup
Keyword(s):  
Wave Breaking ◽  
Gas Transfer ◽  
Water Gas

Study on air-sea CO2 exchange with wave breaking

2020 ◽  
Author(s):  
Shuo Li ◽  
Alexander Babanin ◽  
Fangli Qiao ◽  
Dejun Dai ◽  
Shumin Jiang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Gas Exchange ◽  
Significant Role ◽  
Wave Breaking ◽  
Co2 Exchange ◽  
Gas Transfer ◽  
Data Sets ◽  
Transfer Velocity ◽  
Ocean Surface Waves ◽  
Hydrodynamic Processes

<p>Hydrodynamic processes at air-sea interface play a significant role on air-sea CO<sub>2</sub> gas exchange, which further affects global carbon cycle and climate change. CO<sub>2</sub> gas transfer velocity (K<sub>CO2</sub>) is generally parameterized with wind speed but ocean surface waves have direct impact on the gas exchange. Thus, the relationship between wave breaking and CO<sub>2</sub> gas exchange was studied through laboratory experiments and by utilizing field campaign data. The results from laboratory show that wave breaking plays a significant role in CO<sub>2</sub> gas exchange in all experiments while wind forcing can also influence K<sub>CO2</sub>. A non-dimensional empirical formula is established in which K<sub>CO2 </sub>is expressed as the product of wave breaking probability, transformed Reynolds number and an enhancement factor of wind speed. The parameterization is then improved by considering the bubble-mediated gas transfer based on both laboratory and ship campaign data sets. In the end, the formula is employed in the estimation of global CO<sub>2</sub> uptake by ocean and the result is found consistent with reported values.</p>

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