AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Regional Signatures from Seawater in Atmospheric Particles
AMANDA FROSSARD, Lynn Russell, Patricia Quinn, Timothy Bates, Scott Elliot, Scripps Institution of Oceanography
Abstract Number: 266 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Marine aerosol particles play an important role in the earth’s radiative balance, yet the sources and composition of the organic fraction remain largely unconstrained. Recent measurements have been made in order to characterize the sources, composition, and concentration of particles in the marine boundary layer. The organic compositions of submicron particles derived from multiple seawater regions have been measured using Fourier Transform Infrared (FTIR) spectroscopy. Cluster analysis of FTIR organic spectra suggest different spectral signatures based on collection location, seawater composition, and ambient conditions. Measurements including aerosol composition from a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS), seawater composition, and wind speed were used to interpret the cluster results, depending on the availability from each campaign. Recent measurements used in the comparison include ambient and generated marine aerosol particles measured on board the R/V Atlantis during CalNex in May and June 2010. The ambient clean marine particles had an average organic mass (OM) of 0.80 micro-gram m$^(-3) and average chlorophyll and wind speed values of 6 m s$^(-1) and 7 micro-gram L$^(-1), respectively. Additional remote ambient marine aerosol particles were collected 100 miles off the coast of Monterey in the eastern Pacific on board the R/V Point Sur during the EPEACE experiment in July 2011 and had an average OM of 0.64 micro-gram m$^(-3) and an average wind speeds of 7 m s$^(-1). These particles are compared with those measured in the southeastern Pacific during VOCALS and the north Atlantic during ICEALOT. One spectral cluster from the eastern Pacific showed the highest fraction of hydroxyl functional groups (77%), which corresponds to periods of high relative chlorophyll concentrations and high wind speeds (>10 m s$^(-1)).