Editorial Type:
Article
Article Type:
Research Article

Aeration Due to Breaking Waves. Part I: Bubble Populations

A. Graham School of Ocean and Earth Science, Southampton Oceanography Centre, University of Southampton, Southampton, United Kingdom

Search for other papers by A. Graham in
Current site
Google Scholar
PubMed Close
,
D. K. Woolf School of Ocean and Earth Science, Southampton Oceanography Centre, University of Southampton, Southampton, United Kingdom

Search for other papers by D. K. Woolf in
Current site
Google Scholar
PubMed Close
, and
A. J. Hall George Deacon Division, Southampton Oceanography Centre, University of Southampton, Southampton, United Kingdom

Search for other papers by A. J. Hall in
Current site
Google Scholar
PubMed Close
Print Publication:
01 May 2004
DOI:
https://doi.org/10.1175/1520-0485(2004)034<0989:ADTBWP>2.0.CO;2
Page(s):
989–1007
Restricted access

Abstract

The population of bubbles produced by breaking waves in (10 m) winds of up to 12 m s−1 is analyzed using calibrated images from a vertical pencil-beam sonar system placed on the seabed near the Dutch coast. The structure in the images is parameterized, and the volumetric bubble backscatter is inverted to yield bubble concentrations. Data were obtained at three acoustic frequencies, with inversion effected by prescribing a bubble spectrum with two free variables, leaving a redundant measurement to test the robustness of the model. Median concentrations may in this way be obtained up to the sea surface. Measurements are multiply regressed on wind and dominant-wave variables. Bubbles penetrate to a depth of about a factor of 6γ−1 times the significant wave height Hs, where γ is the wave age, or ratio of dominant-wave phase speed to wind speed. The measured mean bubble radius decreases weakly with depth, unless waves are gently sloping, at about 5% m−1. At 0.4 m, the mean radius ranges from 30 to 80 μm and is typically about two-thirds of the radius contributing most to void fraction. The total, depth-integrated surface area of the bubbles and their upward displacement of the sea surface, or “void displacement,” increase as wind speed to the powers 7 ± 1 and 8 ± 1, respectively, dependences ascribed to the preferential breaking of short, steep wind waves. It is estimated, on extrapolating trends, that the total bubble surface area on average is equal to that of the sea surface above them, and the mean void displacement is equal to the mean bubble radius, at a wind speed of about 15 m s−1.

Current affiliation: Department of Environmental and Geographical Sciences, Manchester Metropolitan University, Manchester, United Kingdom

Current affiliation: James Rennell Division, Southampton Oceanography Centre, University of Southampton, Southampton, United Kingdom

Corresponding author address: Dr. A. Graham, Dept. of Environmental and Geographical Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester M1 5GD, United Kingdom. Email: a.graham@mmu.ac.uk

Abstract

The population of bubbles produced by breaking waves in (10 m) winds of up to 12 m s−1 is analyzed using calibrated images from a vertical pencil-beam sonar system placed on the seabed near the Dutch coast. The structure in the images is parameterized, and the volumetric bubble backscatter is inverted to yield bubble concentrations. Data were obtained at three acoustic frequencies, with inversion effected by prescribing a bubble spectrum with two free variables, leaving a redundant measurement to test the robustness of the model. Median concentrations may in this way be obtained up to the sea surface. Measurements are multiply regressed on wind and dominant-wave variables. Bubbles penetrate to a depth of about a factor of 6γ−1 times the significant wave height Hs, where γ is the wave age, or ratio of dominant-wave phase speed to wind speed. The measured mean bubble radius decreases weakly with depth, unless waves are gently sloping, at about 5% m−1. At 0.4 m, the mean radius ranges from 30 to 80 μm and is typically about two-thirds of the radius contributing most to void fraction. The total, depth-integrated surface area of the bubbles and their upward displacement of the sea surface, or “void displacement,” increase as wind speed to the powers 7 ± 1 and 8 ± 1, respectively, dependences ascribed to the preferential breaking of short, steep wind waves. It is estimated, on extrapolating trends, that the total bubble surface area on average is equal to that of the sea surface above them, and the mean void displacement is equal to the mean bubble radius, at a wind speed of about 15 m s−1.

Current affiliation: Department of Environmental and Geographical Sciences, Manchester Metropolitan University, Manchester, United Kingdom

Current affiliation: James Rennell Division, Southampton Oceanography Centre, University of Southampton, Southampton, United Kingdom

Corresponding author address: Dr. A. Graham, Dept. of Environmental and Geographical Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester M1 5GD, United Kingdom. Email: a.graham@mmu.ac.uk

Save
Cover Journal of Physical Oceanography
Journal of Physical Oceanography

  • Agrawal, Y. C., E. A. Terray, M. A. Donelan, P. A. Hwang, A. J. Williams, W. M. Drennan, K. K. Kahma, and S. A. Kitaigorodskii, 1992: Enhanced dissipation of kinetic energy beneath surface waves. Nature, 359 , 219–220.

    • Search Google Scholar
    • Export Citation

  • Akulichev, V. A., V. A. Bulanov, and S. A. Klenin, 1986: Acoustic sensing of gas bubbles in the ocean medium. Sov. Phys. Acoust, 32 , 177–180.

    • Search Google Scholar
    • Export Citation

  • Andrew, R. K., D. M. Farmer, and R. L. Kirlin, 2001: Broad band parametric imaging of breaking ocean waves. J. Acoust. Soc. Amer, 110 , 150–162.

    • Search Google Scholar
    • Export Citation

  • Banner, M. L., 1990: The influence of wave breaking on the surface pressure distribution in wind–wave interactions. J. Fluid Mech, 211 , 463–495.

    • Search Google Scholar
    • Export Citation

  • Banner, M. L., and O. M. Phillips, 1974: On the incipient breaking of small scale waves. J. Fluid Mech, 65 , 647–656.

  • Banner, M. L., and W. K. Melville, 1976: On the separation of air flow over water waves. J. Fluid Mech, 77 , 825–842.

  • Banner, M. L., and W. L. Pierson, 1998: Tangential stress beneath wind-driven air–water interfaces. J. Fluid Mech, 364 , 115–145.

  • Banner, M. L., A. V. Babanin, and I. R. Young, 2000: Breaking probability for dominant waves on the sea surface. J. Phys. Oceanogr, 30 , 3145–3160.

    • Search Google Scholar
    • Export Citation

  • Blanc, T. V., 1985: Variation of bulk-derived surface flux, stability, and roughness results due to the use of different transfer coefficient schemes. J. Phys. Oceanogr, 15 , 650–669.

    • Search Google Scholar
    • Export Citation

  • Clay, C. S., and H. Medwin, 1977: Acoustical Oceanography: Principles and Applications. Wiley, 544 pp.

  • Craig, P. D., and M. L. Banner, 1994: Modeling wave-enhanced turbulence in the ocean surface layer. J. Phys. Oceanogr, 24 , 2546–2559.

  • Dahl, P. H., and A. T. Jessup, 1995: On bubble clouds produced by breaking waves: An event analysis of ocean acoustic measurements. J. Geophys. Res, 100 , 5007–5020.

    • Search Google Scholar
    • Export Citation

  • Ding, L., and D. M. Farmer, 1994: Observations of breaking surface wave statistics. J. Phys. Oceanogr, 24 , 1368–1387.

  • Dobson, F. W., S. D. Smith, and R. J. Anderson, 1994: Measuring the relationship between wind stress and sea state in the open ocean in the presence of swell. Atmos.–Ocean, 32 , 237–256.

    • Search Google Scholar
    • Export Citation

  • Donelan, M., M. S. Longuet-Higgins, and J. S. Turner, 1972: Periodicity in whitecaps. Nature, 239 , 449–451.

  • Donelan, M., W. M. Drennan, and K. B. Katsaros, 1997: The air–sea momentum flux in conditions of wind sea and swell. J. Phys. Oceanogr, 27 , 2087–2099.

    • Search Google Scholar
    • Export Citation

  • Farmer, D. M., S. Vagle, and A. D. Booth, 1998: A free-flooding acoustical resonator for measurement of bubble size distributions. J. Atmos. Oceanic Technol, 15 , 1132–1146.

    • Search Google Scholar
    • Export Citation

  • Garrett, C., M. Li, and D. Farmer, 2000: The connection between bubble size spectra and energy dissipation rates in the upper ocean. J. Phys. Oceanogr, 30 , 2163–2171.

    • Search Google Scholar
    • Export Citation

  • Geernaert, G. L., K. B. Katsaros, and K. Richter, 1986: Variation of the drag coefficient and its dependence on sea state. J. Geophys. Res, 91 , 7667–7679.

    • Search Google Scholar
    • Export Citation

  • Gemmrich, J. R., and D. M. Farmer, 1999: Observations of the scale and occurrence of breaking surface waves. J. Phys. Oceanogr, 29 , 2595–2606.

    • Search Google Scholar
    • Export Citation

  • Graham, A., 2004: Aeration due to breaking waves. Part II: Fluxes. J. Phys. Oceanogr, 34 , 1008–1018.

  • Graham, A., and A. J. Hall, 1997: The horizontal distribution of bubbles in a shallow sea. Cont. Shelf Res, 17 , 1051–1082.

  • Hwang, P. A., Y-H. L. Hsu, and J. Wu, 1990: Air bubbles produced by breaking wind waves: A laboratory study. J. Phys. Oceanogr, 20 , 19–28.

    • Search Google Scholar
    • Export Citation

  • Jago, C. F., and S. E. Jones, 1998: Observation and modelling of the dynamics of benthic fluff resuspended from a sandy bed in the southern North Sea. Cont. Shelf Res, 18 , 1255–1282.

    • Search Google Scholar
    • Export Citation

  • Jessup, A. T., and V. Hesany, 1996: Modulation of ocean skin temperature by swell waves. J. Geophys. Res, 101 , 6501–6511.

  • Jessup, A. T., C. J. Zappa, M. R. Loewen, and V. Hesany, 1997: Infrared remote sensing of breaking waves. Nature, 385 , 52–55.

  • Kinsman, B., 1984: Wind Waves: Their Generation and Propagation on the Ocean Surface. Dover, 676 pp.

  • Kolovayev, P. A., 1975: Investigation of the concentration and statistical size distribution of wind-produced bubbles in the near-surface ocean layer. Oceanology, 15 , 659–661.

    • Search Google Scholar
    • Export Citation

  • Kolovayev, P. A., and A. Kh Dekterev, 1992: On the concentration and statistical distribution of the sizes of air bubbles produced by the wind in coastal waters of the Black Sea. Oceanology, 32 , 305–308.

    • Search Google Scholar
    • Export Citation

  • Kraan, C., W. A. Oost, and P. A. E. M. Janssen, 1996: Wave energy dissipation by whitecaps. J. Atmos. Oceanic Technol, 13 , 262–267.

  • Lamarre, E., and W. K. Melville, 1991: Air entrainment and dissipation in breaking waves. Nature, 351 , 469–472.

  • Lamarre, E., and W. K. Melville, 1994: Void-fraction measurements and sound-speed fields in bubble plumes generated by breaking waves. J. Acoust. Soc. Amer, 95 , 1317–1328.

    • Search Google Scholar
    • Export Citation

  • Leibovich, S., 1977: On the evolution of the system of wind drift currents and Langmuir circulations in the ocean. Part 1: Theory and averaged current. J. Fluid Mech, 79 , 715–743.

    • Search Google Scholar
    • Export Citation

  • Liss, P. S., and P. G. Slater, 1974: Flux of gases across the air–sea interface. Nature, 247 , 181–184.

  • Liss, P. S., and Coauthors, 1997: Report Group 1—Physical processes in the microlayer and the air–sea exchange of trace gases. The Sea Surface and Global Change, P. S. Liss and R. A. Duce, Eds., University Press, 1–33.

    • Search Google Scholar
    • Export Citation

  • Longuet-Higgins, M. S., 1987: The propagation of short surface waves on longer gravity waves. J. Fluid Mech, 177 , 293–306.

  • Longuet-Higgins, M. S., and E. D. Cokelet, 1976: The deformation of steep surface waves on water. I. A numerical method of computation. Proc. Roy. Soc. London, A350 , 1–26.

    • Search Google Scholar
    • Export Citation

  • Longuet-Higgins, M. S., and E. D. Cokelet, 1978: The deformation of steep surface waves on water. II. Growth of normal-mode instabilities. Proc. Roy. Soc. London, A364 , 1–28.

    • Search Google Scholar
    • Export Citation

  • Medwin, H., 1977: Counting bubbles acoustically: A review. Ultrasonics, 15 , 7–13.

  • Medwin, H., and N. D. Breitz, 1989: Ambient and transient bubble spectral densities in quiescent seas and under spilling breakers. J. Geophys. Res, 94 , 12751–12759.

    • Search Google Scholar
    • Export Citation

  • Melville, W. K., 1982: The instability and breaking of deep-water waves. J. Fluid Mech, 115 , 165–185.

  • Melville, W. K., 1983: Wave modulation and breakdown. J. Fluid Mech, 128 , 489–506.

  • Melville, W. K., 1994: Energy dissipation by breaking waves. J. Phys. Oceanogr, 24 , 2041–2049.

  • Melville, W. K., 1996: The role of surface-wave breaking in air–sea interaction. Annu. Rev. Fluid Mech, 28 , 279–321.

  • Nimmo Smith, W. A. M., S. A. Thorpe, and A. Graham, 1999: Surface effects of bottom-generated turbulence in a shallow tidal sea. Nature, 400 , 251–254.

    • Search Google Scholar
    • Export Citation

  • Osborn, T., D. M. Farmer, S. Vagle, S. A. Thorpe, and M. Cure, 1992: Measurements of bubble plumes and turbulence from a submarine. Atmos.–Ocean, 30 , 419–440.

    • Search Google Scholar
    • Export Citation

  • Pace, N. G., A. Cowley, and A. M. Campbell, 1997: Short pulse acoustic excitation of microbubbles. J. Acoust. Soc. Amer, 102 , 1474–1479.

    • Search Google Scholar
    • Export Citation

  • Phillips, O. M., 1977: The Dynamics of the Upper Ocean. University Press, 336 pp.

  • Phillips, O. M., 1985: Spectral and statistical properties of the equilibrium range in wind-generated gravity waves. J. Fluid Mech, 156 , 505–531.

    • Search Google Scholar
    • Export Citation

  • Phillips, O. M., and M. L. Banner, 1974: Wave breaking in the presence of wind drift and swell. J. Fluid Mech, 66 , 625–640.

  • Phillips, O. M., F. L. Posner, and J. P. Hansen, 2001: High range resolution radar measurements of the speed distribution of breaking events in wind-generated ocean waves: Surface impulse and wave energy dissipation rates. J. Phys. Oceanogr, 31 , 450–460.

    • Search Google Scholar
    • Export Citation

  • Plueddermann, A. J., J. A. Smith, D. M. Farmer, R. A. Weller, W. R. Crawford, R. Pinkel, S. Vagle, and A. Gnanadesikan, 1996: Structure and variability of Langmuir circulation during the Surface Waves Processes Program. J. Geophys. Res, 101 , 3525–3543.

    • Search Google Scholar
    • Export Citation

  • Rapp, R. J., and W. K. Melville, 1990: Laboratory models of deep-water breaking waves. Philos. Trans. Roy. Soc. London, A331 , 735–800.

    • Search Google Scholar
    • Export Citation

  • Rieder, K. F., and J. A. Smith, 1998: Removing wave effects from the wind stress vector. J. Geophys. Res, 103 , 1363–1374.

  • Rieder, K. F., J. A. Smith, and R. A. Weller, 1996: Some evidence of colinear wind stress and wave breaking. J. Phys. Oceanogr, 26 , 2519–2524.

    • Search Google Scholar
    • Export Citation

  • Smith, M. H., P. M. Park, and I. E. Consterdine, 1993: Marine aerosol concentrations and estimated fluxes over the sea. Quart. J. Roy. Meteor. Soc, 119 , 809–824.

    • Search Google Scholar
    • Export Citation

  • Smith, M. J., E. M. Poulter, and J. A. McGregor, 1996: Doppler radar measurements of wave groups and breaking waves. J. Geophys. Res, 101 , 14269–14282.

    • Search Google Scholar
    • Export Citation

  • Soloviev, A. V., and P. Schlüssel, 1994: Parameterization of the cool skin of the ocean and of the air–ocean gas transfer on the basis of modeling surface renewal. J. Phys. Oceanogr, 24 , 1339–1346.

    • Search Google Scholar
    • Export Citation

  • Suiter, H. R., 1992: Pulse length effects on the transmissivity of bubbly water. J. Acoust. Soc. Amer, 91 , 1383–1387.

  • Terray, E. A., M. A. Donelan, Y. C. Agrawal, W. M. Drennan, K. K. Kahma, A. J. Williams, P. A. Hwang, and S. A. Kitaigorodskii, 1996: Estimates of kinetic energy dissipation under breaking waves. J. Phys. Oceanogr, 26 , 792–807.

    • Search Google Scholar
    • Export Citation

  • Thorne, P. D., P. J. Hardcastle, D. Flatt, and J. D. Humphery, 1994: On the use of acoustics for measuring shallow water suspended sediment processes. IEEE J. Oceanic Eng, 19 , 48–57.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., 1982: On the clouds of bubbles formed by breaking wind-waves in deep water, and their role in air–sea gas transfer. Philos. Trans. Roy. Soc. London, A304 , 155–210.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., 1984: The effect of Langmuir circulation on the distribution of submerged bubbles caused by breaking wind waves. J. Fluid Mech, 114 , 237–250.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., 1986: Measurements with an automatically recording inverted echo sounder; ARIES and the bubble clouds. J. Phys. Oceanogr, 16 , 1462–1478.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., 1992: Bubble clouds and the dynamics of the upper ocean. Quart. J. Roy. Meteor. Soc, 118 , 1–22.

  • Thorpe, S. A., 1993: Energy loss by breaking waves. J. Phys. Oceanogr, 23 , 2498–2502.

  • Thorpe, S. A., 1995: Dynamical processes of transfer at the sea surface. Progress in Oceanography, Vol. 35, Pergamon, 315–352.

  • Thorpe, S. A., and A. J. Hall, 1980: The mixing layer of Loch Ness. J. Fluid Mech, 101 , 687–703.

  • Thorpe, S. A., and A. J. Hall, 1983: The characteristics of breaking waves, bubble clouds, and near-surface currents observed using side-scan sonar. Cont. Shelf Res, 1 , 353–384.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., P. Bowyer, and D. K. Woolf, 1992: Some factors affecting the size distributions of oceanic bubbles. J. Phys. Oceanogr, 22 , 382–389.

    • Search Google Scholar
    • Export Citation

  • Thorpe, S. A., M. S. Cure, A. Graham, and A. J. Hall, 1994: Sonar observations of Langmuir circulation, and estimation of dispersion of floating particles. J. Atmos. Oceanic Technol, 11 , 1273–1294.

    • Search Google Scholar
    • Export Citation

  • Vagle, S., and D. M. Farmer, 1992: The measurement of bubble-size distributions by acoustical backscatter. J. Atmos. Oceanic Technol, 9 , 630–644.

    • Search Google Scholar
    • Export Citation

  • Walsh, A. L., and P. J. Mulhearn, 1987: Photographic measurements of bubble populations from breaking wind waves at sea. J. Geophys. Res, 92 , 14553–14565.

    • Search Google Scholar
    • Export Citation

  • Woolf, D. K., 1993: Bubbles and the air–sea transfer velocity of gases. Atmos.–Ocean, 31 , 517–540.

  • Wu, J., 1995: Small-scale wave breaking: A widespread sea surface phenomenon and its consequence for air–sea exchanges. J. Phys. Oceanogr, 25 , 407–412.

    • Search Google Scholar
    • Export Citation

  • Zedel, L., and D. Farmer, 1994: Surface wave period modulations in near surface ambient sound. J. Geophys. Res, 99 , 8041–8052.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 649 197 46
PDF Downloads 303 86 2