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Production and Removal at the sea-air interface

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Production and Removal at the sea-air interface

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  1. Dependence of spray flux on breaking wavesFairall, C AF: NOAA / ETL, 325 Broadway, Boulder, CO 80305 United States M.Bannerand Morison, R The University Of New South Wales, School of Mathematics, The University of New South Wales, Sydney, NSW 2052 Australia Peirson, WThe University Of New South Wales, Civil Engineering, The University of New South Wales, Sydney, NSW 2052 Australia

  2. Production and Removal at the sea-air interface 1 2 3 4 5 1 Turbulent xport 2 Molecular diff. 3 Mean fall speed 4 Inertia 5 Source Number(r)/m^2/sec HOWEVER: At least one additional piece of information is required to characterize the soure. *Initial ejection velocity Wej *Effective height h Rate of change=Inputs-Removal=Source-Deposition For concentration n (#/volume)

  3. Source function whitecap scaling:A single whitecap produces sea spray distribution swhitecap[r]

  4. Scaling Arguments

  5. Source Scaling with Forcing • Forcing = • Whitecap fraction • U3 • U*3 • DE2/3 • DE Energy going into wave breaking • Л(c) length of breaking waves per unit area

  6. Droplet Source Functions Fairall et al. 1994 Fairall, Banner, Asher Physical Model h Sig wave height/2 P energy wave breaking σ surface tension r droplet radius η Kolmogorov microscale f fraction of P going into droplet production Vf=droplet mean fall velocity

  7. SPANDEX – SPUME Droplet StudyPhotograph of PDA and DMT probes for the Spray Production and Dynamics Experiment (Water Research Facility, Manly, Australia; January 2003).Bill Asher, Mike Banner, Chris Fairall, Bill Peirson

  8. Droplet Source Strength: Deduced from droplet concentration data Above the source region, Sn =0. Vertical transport balances fall velocity in equilibrium so constant=0 Within source region, Sn≈ Vg n

  9. Samples from Wind Tunnel StudySPANDEX Droplet spectra profiles Droplet spectra normalized by power law equation

  10. Source Function Scaled by Friction Velocity Total near-surface droplet mass and the estimated mass flux near the surface (z=12.5 and 15.0 cm) as a function of u*. The SPANDEX data are indicated by circles. The red line represents the parameterization of Fairall et al. (1994) and the green solid line a recent update of that parameterization obtained from a physically-based model (Fairall et al., 2005).

  11. Source Function Scaled by Small-Scale Wave Energy

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