Laser-Induced Fluorescence Studies of Oxygen Transfer Across Unsheared Flat and Wavy Air−Water Interfaces

Woodrow, Jr. and Philip T.; Duke, Steve R.

doi:10.1021/ie000321j

Cited by 42 publications

(27 citation statements)

References 19 publications

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“…The molecular diffusivity D may vary according to the fluid temperature and the presence of other solutes. Within the turbulent well-mixed bulk, spatial gradients in the down-and cross-wind directions are negligible, but very close to the interface this is not the case (Woodrow & Duke 2001;Takehara & Etoh 2002).…”

Section: Microphysicsmentioning

confidence: 93%

“…The LIF procedures employed during these experiments are described in detail in Walker & Peirson (2008) and were developed for practical application to strongly forced laboratory conditions by extending the techniques originally developed by Wolff & Hanratty (1994) and Woodrow & Duke (2001). Parallel techniques employing HCl and CO 2 have been developed by Münsterer & Jähne (1998) and Takehara & Etoh (2002) respectively.…”

Section: Lif Image Capture and Processing Techniquesmentioning

confidence: 99%

“…Scriven & Pigford (1958) showed that the saturation concentration must exist at the surface. Linear extrapolation of the maximum concentration gradient to the surface yielded concentrations at the surface that were consistently less than the saturation concentration (see also Woodrow & Duke 2001). The error function profile was selected because it is the solution to Fick's law (see (2.4)) for unsteady re-aeration of an aqueous medium of initially uniform concentration C B with aqueous interfacial concentration C I , the solution of which yields…”

Section: Lif Image Capture and Processing Techniquesmentioning

confidence: 99%

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On the microphysical behaviour of wind-forced water surfaces and consequent re-aeration

2014

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A detailed laboratory investigation of the mechanical and low-solubility gas coupling between wind and water has been undertaken using a suite of microphysical measurement techniques. Under a variety of wind conditions and in the presence and absence of mechanically generated short waves, approximately fetch-independent surface conditions have been achieved over short laboratory fetches of several metres. The mechanical coupling of the surface is found to be consistent with Banner (J. Bulk observations of re-aeration are consistent with previous laboratory studies. The surface kinematical behaviour is in accordance with the observations of Peirson & Banner (J. Fluid Mech. vol. 479, 2003, pp. 1-38). Also, their predictions of a strong enhancement of low-solubility gas flux at the onset of microscale breaking is confirmed and direct observations show a concomitant onset of very thin aqueous diffusion sublayers. It is found that the development of strong parasitic capillary waves towards the incipient breaking limit does not noticeably enhance constituent transfer. Across the broad range of conditions investigated during this study, the local instantaneous constituent transfer rate remains approximately log-normally distributed with an approximately constant standard deviation of 0.62 ± 0.15(log e (m s −1 )). Although wind-forced water surfaces are shown to be punctuated by intense tangential stresses and local surface convergence, localized surface convergence does not appear to be the single critical factor determining exchange rate. Larger-scale orbital wave straining is found to be a significant constituent transfer process in contrast to Witting (J. Fluid Mech. vol. 50, 1971, pp. 321-334) findings for heat fluxes, but the measured effects are consistent with his model. By comparing transfer rates in the presence and absence of microscale breaking, low-solubility gas transfer was decomposed into its turbulent/capillary ripple, gravity-wave-related and microscale breaking contributions. It was found that an efficiency factor of approximately 17 % needs to be applied to Peirson & Banner's model, which is extended to field conditions. Although bulk thermal effects were observed and thermal diffusion layers are presumed thicker than their mass diffusion counterparts, significant thermal influences were not observed in the results.

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Section: Microphysicsmentioning

confidence: 93%

Section: Lif Image Capture and Processing Techniquesmentioning

confidence: 99%

Section: Lif Image Capture and Processing Techniquesmentioning

confidence: 99%

See 1 more Smart Citation

On the microphysical behaviour of wind-forced water surfaces and consequent re-aeration

2014

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“…Image processing was performed, involving noise removal, water surface detection, correction of laser attenuation, and correction of optical blurring near the interface. The image processing procedure is described in details by Janzen (2006), being the same of that described by Woodrow and Duke (2001) and Herlina and Jirka (2004).…”

Section: Methodsmentioning

confidence: 99%

Concentration fields near air-water interfaces during interfacial mass transport: oxygen transport and random square wave analysis

Schulz

Janzen

2009

Braz. J. Chem. Eng.

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-Mass transfer across a gas-liquid interface was studied theoretically and experimentally, using transfer of oxygen into water as the gas-liquid system. The experimental results support the conclusions of a theoretical description of the concentration field that uses random square waves approximations. The effect of diffusion over the concentration records was quantified. It is shown that the peak of the normalized rms concentration fluctuation profiles must be lower than 0.5, and that the position of the peak of the rms value is an adequate measure of the thickness of the diffusive layer. The position of the peak is the boundary between the regions more subject to molecular diffusion or to turbulent transport of dissolved mass.

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“…In addition, novel experimental methodologies and detailed microphysical proCorrespondence to: W. E. Asher (asher@apl.washington.edu) cess studies have provided new information concerning the fundamental mechanisms controlling air-water gas exchange (Asher and Litchendorf, 2009;Jirka, 2004, 2008;McKenna and McGillis, 2004;Münsterer and Jähne, 1998;Siddiqui et al, 2004;Woodrow and Duke, 2001;. These field and laboratory data have been used in developing and testing air-sea gas exchange dependencies and have allowed commonly used conceptual models to be tested.…”

Section: Introductionmentioning

confidence: 99%

The effects of experimental uncertainty in parameterizing air-sea gas exchange using tracer experiment data

Asher

2009

Atmos. Chem. Phys.

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Abstract. It is not practical to measure air-sea gas fluxes in the open ocean for all conditions and areas of interest. Therefore, in many cases fluxes are estimated from measurements of air-phase and water-phase gas concentrations, a measured environmental forcing function such as wind speed, and a parameterization of the air-sea transfer velocity in terms of the environmental forcing function. One problem with this approach is that when direct measurements of the transfer velocity are plotted versus the most commonly used forcing function, wind speed, there is considerable scatter, leading to a relatively large uncertainty in the flux. Because it is known that multiple processes can affect gas transfer, it is commonly assumed that this scatter is caused by single-forcing function parameterizations being incomplete in a physical sense. However, scatter in the experimental data can also result from experimental uncertainty (i.e., measurement error). Here, results from field and laboratory results are used to estimate how experimental uncertainty contributes to the observed scatter in the measured fluxes and transfer velocities as a function of environmental forcing. The results show that experimental uncertainty could explain half of the observed scatter in field and laboratory measurements of air-sea gas transfer velocity.

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Laser-Induced Fluorescence Studies of Oxygen Transfer Across Unsheared Flat and Wavy Air−Water Interfaces

Cited by 42 publications

References 19 publications

On the microphysical behaviour of wind-forced water surfaces and consequent re-aeration

On the microphysical behaviour of wind-forced water surfaces and consequent re-aeration

Concentration fields near air-water interfaces during interfacial mass transport: oxygen transport and random square wave analysis

The effects of experimental uncertainty in parameterizing air-sea gas exchange using tracer experiment data

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