A New Optical Bubble Measuring Device; A Simple Model for Bubble Contribution to Gas Exchange

Jähne, Bernd; Wais, T.; Barabás, Miklós

doi:10.1007/978-94-017-1660-4_22

Cited by 19 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to Keeling (1993) three size regimes could be considered: 1) small bubbles with radius (r) r<5×10 −5 m which completely disappear by dissolution in the water, 2) intermediate bubbles in which the gases equilibrate with gases dissolved in the water and 3) large bubbles with r>5×10 −4 m in which oxygen is not in equilibrium with the water (Jahne et al, 1984;Memery and Merlivat, 1985). All three classes may be important in oxygen transfer.…”

Section: Introductionmentioning

confidence: 99%

Gas transfer under breaking waves: experiments and an improved vorticity-based model

Tsoukala

Moutzouris²

2008

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. In the present paper a modified vorticity-based model for gas transfer under breaking waves in the absence of significant wind forcing is presented. A theoretically valid and practically applicable mathematical expression is suggested for the assessment of the oxygen transfer coefficient in the area of wave-breaking. The proposed model is based on the theory of surface renewal that expresses the oxygen transfer coefficient as a function of both the wave vorticity and the Reynolds wave number for breaking waves.Experimental data were collected in wave flumes of various scales: a) small-scale experiments were carried out using both a sloping beach and a rubble-mound breakwater in the wave flume of the Laboratory of Harbor Works, NTUA, Greece; b) large-scale experiments were carried out with a sloping beach in the wind-wave flume of Delft Hydraulics, the Netherlands, and with a three-layer rubble mound breakwater in the Schneideberg Wave Flume of the Franzius Institute, University of Hannover, Germany.The experimental data acquired from both the small-and large-scale experiments were in good agreement with the proposed model. Although the apparent transfer coefficients from the large-scale experiments were lower than those determined from the small-scale experiments, the actual oxygen transfer coefficients, as calculated using a discretized form of the transport equation, are in the same order of magnitude for both the small-and large-scale experiments. The validity of the proposed model is compared to experimental results from other researchers.Although the results are encouraging, additional research is needed, to incorporate the influence of bubble mediated gas exchange, before these results are used for an environmental friendly design of harbor works, or for projects involving waste disposal at sea.

show abstract

Section: Introductionmentioning

confidence: 99%

Gas transfer under breaking waves: experiments and an improved vorticity-based model

Tsoukala

Moutzouris²

2008

Ann. Geophys.

View full text Add to dashboard Cite

show abstract

“…The transfer velocities themselves are not affected. A detailed analysis of the time scales involved and how they depend on the bubble radius is given in Jähne et al (1984).…”

Section: Bubble Mediated Gas Transfermentioning

confidence: 99%

“…The processes mirroring bubbles in the water, spray droplets in the air, is less well studied, with the exception of the transfer of water vapor and heat (Mestayer and Lefauconnier, 1988;Andreas and Emanuel, 2001;Zheng et al, 2008). Only recently, Andreas et al (2017), evaluated the time scales governing spray-mediated gas transfer for gases other than water vapor in a similar fashion as Jähne et al (1984) did for bubble-mediated transfer more than three decades earlier.…”

Section: Spray Mediated Gas Transfermentioning

confidence: 99%

Air-sea gas exchange at hurricane wind speeds

Krall¹,

Jähne²

2019

Preprint

View full text Add to dashboard Cite

Abstract. Gas transfer velocities were measured in two high-speed wind-wave tanks (Kyoto University and the SUSTAIN facility, RSMAS, University of Miami) using fresh water, simulated seawater and seawater for wind speeds between 7 and 80 m s−1. Using a mass balance technique, transfer velocities of a total of 12 trace gases were measured, with dimensionless solubilities ranging from 0.005 to 150 and Schmidt numbers between 149 and 1360. This choice of tracers allowed to separate gas transfer across the free interface from gas transfer at closed bubble surfaces. The major effect found was a very steep increase of the gas transfer across the free water surface at wind speeds beyond 33 m s−1, which is the same for fresh water, simulated seawater and seawater. This steep increase might start at a lower wind speed in the open ocean as compared to the short-fetch wind-wave tanks. Bubble-induced gas transfer plays no significant role for all tracers in fresh water and for tracers with moderate solubility such as carbon dioxide and DMS in seawater, while for low solubility tracers bubble-induced gas transfer in seawater was found to be about 1.7 times larger than the transfer at the free water surface at the highest wind speed of 80 m s−1.

show abstract

“…As mentioned in Section 2.1, the Fairall et al [13] parameterisation has been constrained to allow for variation of ozone diffusivity in water due to temperature [30] and salinity [33] and variation of ozone solubility with temperature [34]. Using box model simulations, the effect of SST on the deposition velocity was investigated for typical North Eastern Atlantic conditions (wind speed of 8 m s −1 and oceanic reactivity of 500 s −1 ).…”

Section: Sensitivity Of Deposition Velocity To Sea-surface Temperaturmentioning

confidence: 99%

Regional‐Scale Ozone Deposition to North‐East Atlantic Waters

Coleman

Varghese

Tripathi

et al. 2010

Advances in Meteorology

View full text Add to dashboard Cite

A regional climate model is used to evaluate dry deposition of ozone over the North East Atlantic. Results are presented for a deposition scheme accounting for turbulent and chemical enhancement of oceanic ozone deposition and a second non-chemical, parameterised gaseous dry deposition scheme. The first deposition scheme was constrained to account for sea-surface ozone-iodide reactions and the sensitivity of modelled ozone concentrations to oceanic iodide concentration was investigated. Simulations were also performed using nominal reaction rate derived fromin-situozone deposition measurements and using a preliminary representation of organic chemistry. Results show insensitivity of ambient ozone concentrations modelled by the chemical-enhanced scheme to oceanic iodide concentrations, and iodide reactions alone cannot account for observed deposition velocities. Consequently, we suggest a missing chemical sink due to reactions of ozone with organic matter at the air-sea interface. Ozone loss rates are estimated to be in the range of 0.5–6 ppb per day. A potentially significant ozone-driven flux of iodine to the atmosphere is estimated to be in the range of 2.5–500 M moleccm−2 s−1, leading to a mixing-layer enhancement of organo-iodine concentrations of 0.1–22.0 ppt, with an average increase in the N.E. Atlantic of around 4 ppt per day.

show abstract

A New Optical Bubble Measuring Device; A Simple Model for Bubble Contribution to Gas Exchange

Cited by 19 publications

References 2 publications

Gas transfer under breaking waves: experiments and an improved vorticity-based model

Gas transfer under breaking waves: experiments and an improved vorticity-based model

Air-sea gas exchange at hurricane wind speeds

Regional‐Scale Ozone Deposition to North‐East Atlantic Waters

Contact Info

Product

Resources

About