AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Observations of Fluorescent Aerosol at the Maido Observatory on La Reunión
ANNE PERRING, Ellis Shipley Robinson, Mark T. Hernandez, Odessa Gomez, David O'Connor, J. Alex Huffman, Joshua P. Schwarz, Jerome Brioude, Stephanie Evan, Aurelie Colomb, Valentin Duflot, Jean-Marc Metzger, Pierre Tulet, Ru-Shan Gao, David Fahey, CU CIRES- NOAA ESRL
Abstract Number: 563 Working Group: Bioaerosols
Abstract Primary Biological Aerosol Particles (PBAP) may impact atmospheric processes in a number of ways; as a component of aerosol and via potential roles in cloud formation and precipitation. Current observations, however, are inadequate to assess the true atmospheric importance of PBAP on global or regional scales especially in remote marine environments and the Southern Hemisphere. Here we present measurements of fluorescent aerosol (a proxy for PBAP) made at the Maido Observatory on the French island of La Reunión in the southern Indian Ocean. Two Wide-Band Integrated Bioaerosol Sensors (WIBS 4A) were run at staggered gain to detect particles of diameter ~0.3 um to 15 um. Strong diurnal cycles in both total particle and fluorescent particle loadings were observed. The fraction of fluorescent particles was 2-20%. Particle concentrations were much higher during the day than at night, however the fluorescent fraction often varied inversely. We examine the relationship of fluorescent aerosol loadings and characteristics to meteorological conditions and other particle- and gas-phase tracers. We also use the measured single-particle fluorescent signals and optical size distributions to infer relative contributions of bacteria and fungal spores to the observed loadings. Typical diurnal flow patterns at the observatory result in sampling predominantly local island sources during the day and airmasses from a larger geographical area at night. We use this to examine fluorescent aerosol loadings and characteristics from both local island sources and the larger surrounding marine environment.