AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Organic Composition of Submicron Aerosols in Cloud and Below Cloud in La Jolla, California: the Role of Organic Aerosols in Cloud Formation
ASHLEY CORRIGAN, Rob Modini, Anita Johnson, Janin Guzman Morales, Lynn Russell, Desiree Toom-Sauntry, Annie-Marie Macdonald, John Liggio, Richard Leaitch, Jason Schroder, Allan Bertram, Alex K. Y. Lee, Ran Zhao, Jonathan Abbatt, Scripps Institution of Oceanography, UCSD
Abstract Number: 756 Working Group: Aerosols, Clouds, and Climate
Abstract Submicron particles were collected from May 8- July 4, 2012 at two platforms in La Jolla, CA: Mount Soledad (251 masl) and Scripps Institution of Oceanography pier (14 masl) to investigate the role of organic and black carbon aerosol in and below cloud base. A counterflow virtual impactor (CVI) was used to sample cloud residuals during cloud events on Mount Soledad. During cloud events, chemical composition of cloud residuals was analyzed by aerosol mass spectrometry (AMS), single particle soot photometer (SP2), photo acoustic soot photometer (PASS), and chemical ionization mass spectrometry (CIMS). Organic composition of atmospheric aerosol at both platforms was measured using Fourier transform infrared (FTIR) spectroscopy, aerosol mass spectrometry (AMS at Mount Soledad), and aerosol chemical speciation monitor (ACSM at SIO Pier), to determine differences in organic aerosol in and below cloud base. Campaign average organic functional groups from Fourier transform infrared (FTIR) analysis of PM1 aerosol included alkane, carboxylic acid, organic hydroxyl, organonitrate, non-carboxylic acid carbonyl, and primary amine. Measurements of particle-phase organic functional groups and inorganic ions collected during the Mount Soledad campaign are compared with gas-phase and inorganic aerosol precursors to elucidate controlling factors on secondary organic aerosol formation. Preliminary results indicate the important role organic aerosols play in marine stratocumulus cloud formation.