A Sea-Spray Thermodynamic Parameterization Including Feedback C. W. Fairall *, J-W. Bao, and J....

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A Sea-Spray Thermodynamic Parameterization Including Feedback C. W. Fairall *, J-W. Bao, and J. Wilczak NOAA Environmental Technology Laboratory (ETL) Boulder, CO 1. Background 2. Source strength 3. Feedback 4. Sensitivities 5. Model tests

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Original Droplet Equations Fairall/Andreas circa 1990

Transcript of A Sea-Spray Thermodynamic Parameterization Including Feedback C. W. Fairall *, J-W. Bao, and J....

A Sea-Spray Thermodynamic Parameterization Including Feedback C. W. Fairall *, J-W. Bao, and J. Wilczak NOAA Environmental Technology Laboratory (ETL) Boulder, CO 1.Background 2.Source strength 3.Feedback 4.Sensitivities 5.Model tests Original Droplet Equations Fairall/Andreas circa 1990 S n Surface Source Strength for Sea Spray Droplets Droplet Source Functions P energy wave breaking surface tension r droplet radius Kolmogorov microscale f fraction of P going into droplet production V f =droplet mean fall velocity Fairall et al Fairall, Banner, Asher Physical Model Feedback Partitioning of Droplet Contribution: Stages of cooling/evaporation Simplification: consider large droplets that are ejected, cool to wet bulb temperature and re-enter ocean with negligible change in mass Stages: Cool from To to Tair = Qs Cool from Tair to Twet = Ql_a Evaporation while at Twet = Ql_b Total droplet enthapy transfer Qse=Qs+Ql_a Enthalpy Bowen ratio = Qs/Ql_a=(To-Ta)/(Ta-Twet) Qs=Qse*bowen/(1+bowen) Feedback Characterization T a Effect on the fluxes: Turbulent Fluxes Above the Droplet Evaporation Layer Direct Transfer Coefficients Assumed in Parameterization Ratio of Transfer Coefficients With Droplet Enthalpy Flux Feedback Sensitivity: Source Strength=0.3 Model Tests (Bao and Ginis) IVAN, ISABEL GFDL operational GFDL new zo, zt WRF PLANS HWRF at high resolution matrix of tune values Explicit droplet model (Kepert/ Fairall) in HWRF Coordinate with Penn State LES work Simulation with GFDL Operational Model: Isabel But: Simulations with New Cd and Ce/Ch New Cd Ce/Ch Old Cd Ce/Ch