A micrometeorological investigation of surface exchange parameters

Abstract

An automated system for measuring the dry deposition fluxes of SO2 on a routine basis based on the micrometeorological gradient technique has been developed. The ability of the system to determine turbulent exchange parameters such as the friction velocity u* and the heat flux H was investigated by comparison with an automated eddy correlation system. Determination of u* and H by both methods have generally been found to be in very good agreement for 20 minute averages. Aerodynamic resistances derived from both systems showed no systematic differences but individual values differed considerably. From the analysis it appeared that apart from classical rejection criteria on wind speed and inhomogeneity etc. also measuring cycles with large shift in wind direction have to be removed from the dataset before interpretation.