Probing the acid deposition system with a semi-empirical model: The role of oxidant limitation

This paper demonstrates the use of semi-empirical models in understanding the behavior of observations made on the acid deposition system. The analysis involves fitting a semi-empirical model to annually averaged values of concentrations of sulfur in rain. It is found that the model explains over 80% of the variance of the observations. The values of the parameters obtained by the fitting procedure provide insight into the processes governing the observations. For example, we find that the parameter used to represent the oxidant concentration assumes the value of an H₂O₂ equivalent concentration of 1 ppb. This suggests the importance of oxidant limitation in the wet deposition of S.