A Unified Air-Sea Flux Parameterization Incorporating Winds, Waves, and Sea Spray Generation

In this paper we report on the development of a parameterization structure for the estimation of the fluxes of momentum, sensible heat, and latent heat over the ocean. The parameterization is principally intended for use in coupled air-ocean-wave models. It is based on a combination of the NOAA COARE bulk flux parameterization and the Fairall-Banner-Morrison (FBM) sea spray parameterization. COARE3.5 is the latest version (Edson et al., 2013). It has been fit to 15,000 hrs of direct covariance flux data for wind speeds from 0 – 25 m/s. The original FBM model (documented in Fairall et al. 2009) is a scaling model where sea spray is produced by breaking waves. Droplet production is driven by energy dissipated by wave breaking. Ejection into the atmospheric flow is scaled by wind speed, slope of the dominant wave. Droplet evaporation physics are used to compute the effects of the spray on the total (direct and spray-mediated) heat and moisture fluxes. The COARE and FBM models have been upgraded based on idealized wave model calculations using the UNSW wave model. The wind stress in the COARE data and the wave model are well-described by a Charnock parameter, alpha, of the form alpha=A(U*/cp)^B. The FBM model has been extended to allow use of the spectral version of the wave breaking dissipation. Thus the spray production by each wave-number of the breaking spectrum is computed and the total spray production is the sum over the spectrum. Three version of the code have been developed - fully physical, partially parameterized, and fully parameterized – depending on the data available from the parent coupled model.