SO_2 and O_3 deposition fluxes over Madrid area: results of one year deposition field experiment

摘要

Dry deposition flux of trace gases is often parameterized in models as the concentration of the trace gas at a specific height multiplied by a deposition velocity (V_d) which depends on atmospheric parameters as well as specific surface parameters. The parameterization of the deposition velocity is usually expressed in terms of aerodynamic resistance, which is a function of the physical state of the atmosphere and a surface resistance, which is a function of the chemical, physical and biological properties of the surface. The parameterization of these resistances is under discussion and Held experiments are essential for this objective. A field experiment during one year has been carried out in the Madrid Area for obtaining O_3 and SO_2 deposition fluxes. For this objective, a sonic anemometer and a fast response ozone sonde have been working during this period to measure the ozone fluxes at 5.0 m in height. In addition, the gradient method has been applied to obtain the SO_2 fluxes. These fluxes are use to derive the deposition velocities and the corresponding parameterization over the area. Results show differences between the Wesely~9 model predictions and observations particularly on diurnal hours. The increase in the resistances can be explained by high water vapour deficits and high light intensities which are typical of the period study and also for the Continental-Mediterranean weather conditions. Further research should be performed in order to model resistances under these typical South European ecosystems.