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Swell and the drag coefficient

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Abstract

Simultaneous measurements of waves and turbulent fluxes were collected from a moored surface buoy in the Philippine Sea. Waves were partitioned into their wind sea and swell components, and the ratio of swell to wind sea energy was used to assign a swell index. The 10-m neutral drag coefficient was calculated using the eddy correlation method. Four hundred hours of data were processed in 30 minute runs for wind speeds 8.5 to 16.5 m s−1 when the peak wave direction was within 90° of the wind direction and included observations during mixed seas, swell dominant, and wind sea dominant conditions. The data were analyzed to explore the influence of swell on the drag coefficient. It was found that when compared to periods of equal wind speed, the drag coefficient was reduced up to 37 % when swell energy was twice that of the wind sea energy. It is believed that this reduction was due to a decrease in the turbulent flux around the swell frequency, suggesting that the swell diminishes the surface aerodynamic roughness.

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References

  • Alves JHGM, Branner ML, Young IR (2003) Revisiting the Pierson-Moskowitz asymptotic limits for fully-developed wind waves. J Phys Oceanogr 33:1301–1323

    Article  Google Scholar 

  • Anctil F, Donelan MA, Drennan WM, Graber HC (1994) Eddy-correlation measurements of air-sea fluxes from a discus buoy. J Atmos Ocean Technol 11(4):1144–1150

    Article  Google Scholar 

  • Andreas EL, Mahrt L, Vickers D (2012) A new drag relation for aerodynamically rough flow over the ocean. J Atmos Sci 69(8):2520–2537

    Article  Google Scholar 

  • Charnock H (1955) Wind stress on a water surface. Quart J Royal Meteorol Soc 81:639–640

    Article  Google Scholar 

  • Chen SS, Zhao W, Donelan MA, Tolman HL (2013) Directional wind–wave coupling in fully coupled atmosphere–wave–ocean models: results from CBLAST-hurricane. J Atmos Sci 70(10):3198–3215

    Article  Google Scholar 

  • Collins CO III, Lund B, Waseda T, Graber HC (2014) On recording sea surface elevation with accelerometer buoys: lessons from ITOP 2010. Ocean Dyn 64(6):895–904

    Article  Google Scholar 

  • Collins III CO, Lund B, Ramos R, Drennan WM, Graber HC (2014b) Wave measurement inter-comparison and platform evaluation during the ITOP (2010) experiment. J Atmos Ocean Tech in press

  • D’Asaro EA, Black PG, Centurioni LR, Harr P, Jayne SR, Lin II, Lee CM, Morzel J, Mrvaljevic RK, Niiler PP, Rainville L, Sanford TB, Tang TY (2011) Typhoon-ocean interaction in the western North Pacific: Part 1. Oceanography 24(4):24–31

    Article  Google Scholar 

  • Donelan MA (1982) The dependence of the aerodynamic drag coefficient on wave parameters. 1st intl. conf. on meteorol. & air-sea interaction of the coastal zone, Amer Meteorol Soc: Boston, pp. 381–387, 1982

  • Donelan MA, Dobson FW (2001) The influence of swell on the drag. Wind stress over the ocean. Cambridge Uvi. Press, New York, pp 181–190

    Book  Google Scholar 

  • Donelan MA, Hamilton J, Hui WH (1985) Directional spectra of wind-generated waves. Phil Trans R Soc Lond A315:509–562

    Article  Google Scholar 

  • Donelan MA, Dobson FW, Smith SD, Anderson RJ (1993) On the dependence of sea surface roughness on wave development. J Phys Oceanogr 23:2143–2149

    Article  Google Scholar 

  • Donelan MA, Drennan WM, Katsaros KB (1997) The air-sea momentum flux in conditions of wind sea and swell. J Phys Oceanogr 27(10):2087–2099

    Article  Google Scholar 

  • Drennan WM (2005a) On parameterisations of air-sea fluxes. In: Atmosphere–ocean Interactions, Vol. 2, WIT Press; pp 1–33

  • Drennan WM, Shay LK (2006) On the variability of the fluxes of momentum and sensible heat. Bound-Layer Meteorol 119(1):81–107

    Article  Google Scholar 

  • Drennan WM, Kahma KK, Donelan MA (1999) On momentum flux and velocity spectra over waves. Bound-Layer Meteorol 92:489–515

    Article  Google Scholar 

  • Drennan WM, Graber HC, Hauser D, Quentin C (2003) On the wave age dependence of wind stress over pure wind seas. J Geophys Res 108:C3

    Article  Google Scholar 

  • Drennan WM, Taylor PK, Yelland MJ (2005) Parameterizing the sea surface roughness. J Phys Oceanogr 35:835–848

    Article  Google Scholar 

  • Drennan WM, Graber HC, Collins CO III, Herrera A, Potter H, Ramos RJ, Williams NJ (2014) EASI: an air-sea interaction buoy for high winds. J Atmos Ocean Technol 31:1397–1409

    Article  Google Scholar 

  • Foreman RJ, Emeis S (2010) Revisiting the definition of the drag coefficient in the marine atmospheric boundary layer. J Phys Oceanogr 40:2325–2332

    Article  Google Scholar 

  • García-Nava, H, Ocampo‐Torres FJ, Osuna P, Donelan MA (2009) Wind stress in the presence of swell under moderate to strong wind conditions. J Geophys Res 114 (C12)

  • Högström U, Smedman A, Sahlée E, Drennan WM, Kahma KK, Pettersson H, Zhang F (2009) The atmospheric boundary layer during swell: a field study and interpretation of the turbulent kinetic energy budget for high wave ages. J Atmos Sci 66(9):2764–2779

    Article  Google Scholar 

  • Högström U, Smedman A, Semedo A, Rutgersson A (2011) Comments on ‘A global climatology of wind-wave interaction’ by K. E. Hanley, S. E. Belcher, P. P. Sullivan. J Phys Oceanogr 842(41):1811–1813

    Article  Google Scholar 

  • Högström U, Rutgersson A, Sahlée E, Smedman AS, Hristov TS, Drennan WM, Kahma KK (2013) Air–sea interaction features in the Baltic Sea and at a Pacific trade-wind site: an inter-comparison study. Bound-Layer Meteorol 147(1):139–163

    Article  Google Scholar 

  • Kahma KK, Calkoen CJ (1992) Reconciling discrepancies in the observed growth of wind-generated waves. J Phys Oceanogr 22:1389–1405

    Article  Google Scholar 

  • Kara AB, Hurlburt HE, Wallcraft AJ (2005) Stability-dependent exchange coefficients for air-se fluxes. J Atmos Ocean J Atmos Ocean Tech 22:1080–1094

    Article  Google Scholar 

  • Kitaigorodskii SA (1962) Applications of the theory of similarity to the analysis of wind-generated wave motion as a stochastic process. Izv Akad Nauk SSR, Geophys Ser 1:105–117

    Google Scholar 

  • Kitaigorodskii, SA (1973) The Physics of Air-Sea Interaction, Isr. 859 Program for Sci Transl Jerus

  • Kitaigorodskii SA, Volkov YA (1965) On the roughness parameter of the sea surface and the calculation of momentum flux in the near-water layer of the atmosphere. Izv, Atmos Ocean Phys 1:973–988

    Google Scholar 

  • Kraus EB, Businger JA (1994) Atmosphere–ocean interaction. Oxford University Press, New York, p 362

    Google Scholar 

  • Miyake M, Stewart R, Burling RW (1970) Spectra and cospectra of turbulence over water. Quart J Royal Meteorol Soc 96(407):138–143

    Article  Google Scholar 

  • Monin AS, Obukhov A (1954) Basic laws of turbulent mixing in the surface layer of the atmosphere. Contrib Geophys Inst Acad Sci USSR 151:163–187

    Google Scholar 

  • Moskowitz L (1964) Estimates of the power spectrums for fully-developed seas for wind speeds of 20 to 40 knots. J Geophys Res 69:5161–5179

    Article  Google Scholar 

  • Obukhov AM (1946) ‘Turbulentnost’ v temperaturnoj–neodnorodnoj atmosfere (turbulence in an atmosphere with a Non-uniform temperature). Trudy Inst Theor Geofiz AN SSSR 1:95–115

    Google Scholar 

  • Pan JD, Wang W, Hwang PA (2005) A study of wave effects on wind stress over the ocean in a fetch- limited case. J Geophys Res 110(C2)

  • Pierson WJ, Moskowitz L (1964) A proposed spectral form for fully developed wind seas based on the similarity theory of S.A. Kitaigorodskii. J Geophys Res 69:5158

    Google Scholar 

  • Potter H, Graber HC, Williams NJ, Collins CO III, Rafael RJ, Drennan WM (2015) In situ measurements of momentum fluxes in typhoons. J Atmos Sci 72:104–118

    Article  Google Scholar 

  • Sahlée E, Drennan WM, Potter H, Rebozo MA (2012) Waves and air‐sea fluxes from a drifting ASIS buoy during the Southern Ocean Gas Exchange experiment. J Geophys Res 117(C8)

  • Smedman, AS, Larsén XG, Högström U, Kahma KK, Pettersson H (2003) Effect of sea state on the momentum exchange over the sea during neutral conditions. J Geophys Res: Oceans 108.C11, 3367

  • Smedman A, Högström U, Sahlée E, Drennan WM, Kahma KK, Pettersson H, Zhang F (2009) Observational study of the marine atmospheric boundary layer characteristics during swell. J Atmos Sci 66:2747–2763

    Article  Google Scholar 

  • Smith SD, Anderson RJ, Oost WA, Kraan C, Maat N, DeCosmo J, Katsaros KB, Davidson KL, Bumke K, Hassee L (1992) Sea surface wind stress and drag coefficients: the HEXOS results. Bound-Layer Meteorol 60:109–142

    Article  Google Scholar 

  • Wu J (1980) Wind stress coefficients over the sea surface near neutral conditions: a revisit. J Phys Oceanogr 10:727–740

    Article  Google Scholar 

Download references

Acknowledgments

ITOP was funded by Office of Naval Research under grant N0014-09-1-0392 with additional support from National Science Foundation (OCE-0526442) for the development of the EASI buoy, and Office of Naval Research (DURIP N00014-09-0818) for funding construction of the second EASI buoy. I appreciate input and guidance from colleagues at the University of Miami that worked on the ITOP project, especially Will Drennan, Hans Graber, and Tripp Collins. I am also grateful to the captains and crew of the R/V Roger Revelle. Finally, I acknowledge the support of the National Research Council for my Postdoctoral Research Associate fellowship.

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Correspondence to Henry Potter.

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Responsible Editor: Jörg-Olaf Wolff

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Potter, H. Swell and the drag coefficient. Ocean Dynamics 65, 375–384 (2015). https://doi.org/10.1007/s10236-015-0811-4

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  • DOI: https://doi.org/10.1007/s10236-015-0811-4

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