AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Vertical Distributions of Bioaerosol Over the Eastern U.S.
ANNE PERRING, Ellis Shipley Robinson, Shang Liu, Joshua P. Schwarz, Ru-Shan Gao, NOAA ESRL
Abstract Number: 60 Working Group: Bioaerosols
Abstract The prevalence of bioaerosol in the atmosphere is relevant to atmospheric chemistry, microbial ecology, and climate. Bioaerosol can act as effective cloud condensation nuclei and ice nuclei, representing a potential feedback between vegetation and precipitation. They often comprise a significant fraction of supermicron aerosol near the surface, and may contribute substantially to total aerosol mass in a variety of environments. Very few measurements are available, however, to constrain loadings of bioaerosol in the free troposphere, thus impeding assessment of their overall importance. Here we present vertical profiles of fluorescent aerosol concentration (a common proxy for bioaerosol) spanning particle sizes from 0.8 to 10 μm, observed over the eastern U.S. during the summer of 2016 using a Wide Band Integrated Bioaerosol Sensor (WIBS). The instrument was installed aboard a NOAA Twin Otter research aircraft which was also equipped with a Printed Optical Particle Sensor (POPS) that measured the concentration and optical size of particles in between 14 nm and 3000 nm. The airspeed and inlet configuration were optimized for efficient sampling of aerosol with diameters up to 10 μm, and vertical profiles extended from 1000’ to 17,500’ AGL, spanning a temperature range relevant to ice formation. 100 hours of data were obtained that cover a latitude range from 30N to 46N and target a variety of potential bioaerosol source regions including forests, croplands, the Gulf of Mexico, and Lake Michigan. Vertical distributions, which showed large day-to-day variability in bioaerosol loadings above the boundary layer, are analyzed in the context of ecological region, meteorology and long-range transport. Bioaerosol mass loadings and number and mass size distributions are compared to those of total aerosol observed with the POPS. Finally, observed vertical profiles are compared to current model parameterizations and implications are discussed.