Numerical Modeling of Sulfur and Nitrogen Chemistry in a Narrow Cold-Frontal Rainband: The Impact of Meteorological and Chemical Parameters

Abstract

Abstract To better understand the impact of various meteorological and chemical parameters on chemical deposition from winter storms, the chemistry and microphysics of a narrow cold-frontal rainband and its associated stratiform region were examined with a two-dimensional numerical cloud model. The peak precipitation was associated with the lifting at the leading edge of the cold front. However, the peak sulfate deposition occurred behind the primary updraft, where melting graupel was the dominant source of precipitation, and in the leading rainband. The peak nitrate deposition occurred behind the main updraft and at the leading edge of the main updraft. Sulfur dioxide, aerosol nitrate, and peroxyacetylnitrate were transported to higher altitudes, while aerosol sulfate, nitric acid, and hydrogen peroxide were depleted by the storm. Examination of the pathways for oxidizing aqueous sulfur dioxide showed that iron-catalyzed aerobic oxidation was an important mechanism for converting sulfur dioxide to sulfat...