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Flux System Characterization of Marine Boundary Layer for Dispersion. Chris Fairall NOAA ETL (Big Cheese) Jeff Hare CIRES / ETL (Flux System) Michelle Ryan STC / ETL (Sondes) Dan Law ETL (Profiler) Dan Wolfe ETL (Profiler, Sondes) Sergio Pezoa ETL (Engineer).
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Flux SystemCharacterization of Marine Boundary Layer for Dispersion Chris Fairall NOAA ETL (Big Cheese) Jeff Hare CIRES / ETL (Flux System) Michelle Ryan STC / ETL (Sondes) Dan Law ETL (Profiler) Dan Wolfe ETL (Profiler, Sondes) Sergio Pezoa ETL (Engineer)
Generation of Turbulence – Modification and characterization of the MBL Mechanical (w’) Convective (T’ & q’)
Instrumentation - turbulence • Ultrasonic anemometer / thermometer • Infrared hygrometer • Infrared carbon dioxide gas analyzer • 3-axis accelerometer / rotation rate
Flux Products • Sensible heat flux (Hs = ρCp<w’T’> ) • Latent heat flux (Hl = ρLe<w’q’> ) • Momentum flux (τ = -ρ <u’w’> ) • Carbon dioxide flux (<w’CO2’> ) • Others (DMS, O3, etc)
Instrumentation – Mean state • Aspirated temperature / relative humidity • Optical rain gauge • Pyranometer / pyrgeometer (thanks, Eric) • Sea surface temperature (snake) • Mean wind (from sonic) • SCS (Survey Depahtment) • Laser wave height • GPS
Instrumentation - other • Ceilometer • Wind profiler • Radiosondes – wind, T / RH profiles • C-band precipitation radar • Cloud radar - Pavlos • Doppler lidar
Particle and Gas Transfer Basic Flux Equation: • z=height above surface • x=size dependent concentration • w’=vertical air motion fluctuation • Dx=size dependent molecular diffusion coeff • Vg=mean gravitational settling velocity, function of particle • ws’= air-particle slip velocity • Sx=size/height dependent source function in flux form For gases, Vg and slip terms are 0; Our cases source=0 Near the surface, we use eddy diffusion representation of turbulent transport
Gas Transfer • Solve a simple differential equation Sc=Dx/νΛ≈10 For gas deposition, Xo=0 and F=-Vdx Xz Complications: Two fluid problem (air – water) such as CO2 Xa=concentration in water; Xw=concentration in water Dimensionless solubility α=Xw/Xa (in equilibrium)
Case for Ozone • Ozone reacts with some chemical,Y, in ocean with rate constant Cxy
Particle Deposition • Function of particle radius, r • Slip velocity represents inertial deposition in molecular layer, Vi