A REEVALUATION OF THE WEBB CORRECTION USING DENSITY-WEIGHTED AVERAGES

Results from a re-evaluation of the flux correction suggested by Webb et al. (Q. J. R. Meteorol. Soc., 106, 85-100, 1980) are presented and discussed. This re-evaluation is based on the equation of continuity as well as the budget equations for dry air, water vapour and atmospheric trace species, where a density-weighted averaging procedure introduced by Hesselberg (Beitr. Phys. fr. Atmos., 12, 141-160, 1926) is used. This averaging procedure seems to be more appropriate than that of Reynolds, especially in the case of atmospheric trace species. The consequences of this flux correction as regards the exchange of atmospheric trace gases between the atmosphere and the ground (vegetation, soil and water) are pointed out.