Dry-air boundary conditions for correction of eddy flux measurements

For measurements of eddy fluxes in the atmospheric boundary layer of gases (such as CO₂) whose average concentration is very large compared to the fluctuations, corrections for air density fluctuations are required. With the boundary condition of no flux of dry air at the surface, the evaporation correction to eddy fluxes is 2.6 times larger than has been estimated with the boundary condition of no mass flux at all at the surface. The heat flux correction is also increased by a few per cent.