Reynolds (*) decomposition is used to obtain fluctuating components of vertical velocity and the scalar of interest, while its fundamental equation multiplies the fluctuating components by atmospheric density to obtain the surface flux.  
A 1988 paper by Baldocchi et al. developed the mathematical and physical assumptions necessary to obtain the one-dimensional transport required by this measurement technique.  This technique assumes that there is no net advection of the energy or gas being measured, but does not require neutral stability like Bowen Ratio Energy Balance method.  The friction velocity, u star, is used to remove periods when it calculates erroneous fluxes.  Reynolds (*) decomposition is used to obtain fluctuating components of vertical velocity and the scalar of interest, while its fundamental equation multiplies the fluctuating components by atmospheric density to obtain the surface flux.  For 10 points, name this micrometeorological technique used by the Ameriflux, CarboEurope, and iLEAPS to measure the direct exchange of energy, water, and other matter between the Earth's surface and atmosphere.
A 1988 paper by Baldocchi et al. developed the mathematical and physical assumptions necessary to obtain the one-dimensional transport required by this measurement technique.  
{Eddy Covariance} [accept {Eddy Correlation} or {EC}] (6) [RA]