Relationships between aerosols and precipitation in the southern Appalachian Mountains



There are many uncertainties associated with aerosol-precipitation interactions, particularly in mountain regions where a variety of processes at different spatial scales influence precipitation patterns. Statistical relationships between aerosols and precipitation were examined in the southern Appalachian Mountains to determine the seasonal and synoptic influences on these relationships, as well as the influence of air mass source region. Precipitation events were identified based on regional precipitation data and classified using a synoptic classification scheme developed for this study and published in a separate manuscript (Kelly et al. 2012). Hourly aerosol data were collected at the Appalachian Atmospheric Interdisciplinary Research (AppalAIR) facility at Appalachian State University in Boone, NC (1110 m asl, 36.215°, –81.680°). Backward air trajectories provided information on upstream atmospheric characteristics and source regions. During the warm season (June–September), greater aerosol loading dominated by larger particles was observed, whereas cool season (November–April) precipitation events exhibited overall lower aerosol loading with an apparent influence from biomass burning particles. A significant relationship between aerosol optical properties and precipitation intensity was observed, which may be indicative of aerosol-induced precipitation enhancement in each season, particularly during warm season non-frontal precipitation.