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Aerosol-Precipitation Interactions in the Southern Appalachian Mountains

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Ginger Marie Kelly (Creator)
Institution
Appalachian State University (ASU )
Web Site: http://www.library.appstate.edu/
Advisor
L. Baker Perry

Abstract: Aerosols directly and indirectly influence the surface energy balance and therefore have an important impact on weather and climate. The indirect effects of aerosols, associated with changes in cloud properties and lifetimes, remain poorly understood. Likewise, 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. Aerosol-precipitation linkages were examined in the southern Appalachian Mountains, guided by the following research questions: 1) How do aerosol properties observed during precipitation events vary by season (e.g., summer vs. winter) and synoptic event type (e.g., frontal vs. orographic); 2) how do they compare between summer (June, July, August) 2009 and 2010, and 3) what influence does air mass source region have on aerosol properties? Precipitation events were identified based on data from the Boone Automated Weather Observing System Station, Boone Environmental and Climate Observing Network station, regional National Weather Service cooperative observer stations, and observations from the Community Collaborative Rain, Hail, and Snow network. Events were classified using a synoptic classification scheme created for this thesis. Hourly aerosol data were collected by the Appalachian Atmospheric Interdisciplinary Research facility at Appalachian State University. Backward air trajectories provided information on upstream atmospheric characteristics and source regions. Warm season precipitation events were characterized by much higher aerosol optical properties, including both natural and anthropogenic aerosols. The presence of larger, hygroscopic organic particles acting as effective cloud condensation nuclei enhanced warm season precipitation. Cool season precipitation events exhibited overall lower aerosol optical properties dominated my small organic particles. The change in aerosol values from event beginning to event maturation suggests that AppalAIR is impacted by hygroscopic particles from regional sources including local biogenic emissions and biomass burning. The methodology employed in this thesis will be useful in aerosol-precipitation studies in other mountainous regions. The synoptic classification scheme created for this thesis characterized precipitation events in the southern Appalachian Mountains and will be important to climate researchers and weather forecasters in understanding orographic processes of precipitation. Aerosol properties associated with precipitation events were investigated and described in terms of seasonal and synoptic patterns. These findings will contribute to the parameterization of aerosols in weather and climate models and will enhance our understanding of future climate change in the southern Appalachian Mountains and other mountainous regions.

Additional Information

Publication
Thesis
Kelly, G.M. (2011). Aerosol-Precipitation Interactions in the Southern Appalachian Mountains. Unpublished master's thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2011