Eddy Covariance Flux

Eddy covariance is a direct method for measuring turbulent fluxes of momentum, heat, moisture, and gases across the air-sea interface. It computes the time-averaged covariance of vertical wind speed with the scalar of interest, w’T’ for sensible heat or w’q’ for moisture, from fast-response sensors sampling at 10 to 20 Hz. A sonic anemometer measures the three wind components and a gas analyzer the CO2 and water vapor; on a ship or buoy, motion correction removes platform heave and tilt. Eddy covariance gives the flux without a bulk transfer coefficient, so it serves as the reference that validates bulk air-sea flux parameterizations.