AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Summertime Maximum of Organic Functional Group Concentrations and High Organic Nitrogen from Ocean Biogenic Aerosols at Coastal West Antarctica during AWARE
JUN LIU, Jeramy Dedrick, Lynn Russell, Andy Vogelmann, Gunnar Senum, Stephen Springston, Chongai Kuang, Janek Uin, Dan Lubin, Anne Jefferson, Scripps Institution of Oceanography
Abstract Number: 795 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Atmospheric aerosols can serve as Cloud Condensation Nuclei (CCN), affecting cloud properties and cloud albedo. Almost fifteen months of continuous observations of aerosol particle and CCN number and organic functional group mass concentrations, as well as selected periods of hygroscopicity measurements, were collected from November 2015 to January 2017 at McMurdo Station (77°51'S, 166°40'E) in West Antarctica. Submicron aerosol particle number and organic functional group mass concentrations both were high during the two summers (357 cm-1 and 0.16 g m-3, December 2015 to March 2016 and October 2016 to December 2017) and decreased to background levels in the winter (58 cm-1 and 0.04 g m-3, April to September 2016). The influence from the local transportation emissions on organic functional group mass concentrations analyzed by Fourier transform infrared spectroscopy (FTIR) was identified by K-means clustering and Positive Matrix Factorization (PMF) of the IR spectra. The seasonal variation after removing these emissions indicates that the background aerosol particles in this region are largely of marine origin and that phytoplankton activity could be affecting primary aerosol formation from sea spray. In addition to amine groups typical of marine conditions, spectra also included peak shifts indicative of carbonyl groups that are consistent with amide and amino acid groups. The hygroscopicity measured by both CCN counter and HTDMA (Humidified Tandem Differential Mobility Analyzer) was nearly constant during the year. The number of CCN was 3-10 times higher in summer than in winter, tracking the change in particle number concentration.