Measurements of the organic fraction of aerosol will be made on the R/V Ron Brown during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) experiment with the overall goal of reducing uncertainty in aerosol/climate interactions. The compounds that constitute the organic fraction in the atmosphere span a wide range of chemical, thermodynamic, and optical properties, none of which are known sufficiently well to be described in global climate models. The data will represent some of the first measurements of organic functional groups in aerosols in the Southern Hemisphere, and will be used to quantify the amount and types of organic compounds and assess the microphysical and optical roles of organic particles in clouds. Fourier Transform Infrared (FTIR) and X-Ray Fluorescence (XRF) spectroscopy, Aerosol Mass Spectrometry (AMS), and Near-Edge X-Ray Absorption Fine Structure Scanning Transmission X-Ray Microscopy (NEXAFS/STXM) will be used to measure aerosol concentrations of elements, organic functional groups, and organic mass. The following aerosol properties will be measured: organic mass and organic-mass-to-organic-carbon ratios (OM/OC) by FTIR and AMS; organic functional groups by FTIR and organic mass fragments by AMS; and single-particle organic composition and morphology by NEXAFS/STXM. The measured organic composition will be analyzed with microphysical and thermodynamic models.
This project provides the opportunity for a graduate student and a postdoctoral researcher to participate in the multinational scientific team for VOCALS. The collaboration will strengthen international ties and contribute to the advancement of science in a developing country. The investigators and students will participate in and contribute to outreach and K-12 educational programs developed for VOCALS. The broader scientific impacts of this work will be an improved understanding of the climate-related effects of organic aerosols.
The project ATM-0744636 studied the organic fraction of aerosol in marine regions, including both research and educational activities. The research activities consisted of measurements and analyses of atmospheric particles. The educational activities included a number of training activities for graduate students and a junior scientist, as well as outreach to the public through internet and an academic enrichment program for high school students. The findings are reported in 12 peer-reviewed publications. Our measurements have quantified the amount and types of organic compounds through measurements in the VOCALS-REx 2008 and the CalNex 2010 field campaigns. Analysis of samples collected on board the NOAA R/V Ronald Brown off the western coast Chile as part of VOCALS-REx 2008 campaign and during the CalNex cruise in 2010 on the R/V Atlantis included Fourier Transform Infrared (FTIR), X-Ray Fluorescence (XRF) spectroscopy, Aerosol Mass Spectrometry (AMS), and Scanning Transmission X-Ray Microscopy Near-Edge X-Ray Absorption Fine Structure (STXM-NEXAFS) to measure the aerosol concentration of elements, organic functional groups, and organic mass. Specifically these three techniques (FTIR, AMS, STXM-NEXAFS) measured the following three properties of particles: (1) organic mass and organic-mass-to-organic-carbon ratios by FTIR and AMS; (2) organic functional groups (alkane, alkene, aromatic, alcohol, carbonyl, organonitrogen, and organosulfur) by FTIR and orrganic mass fragments by AMS; and (3) single-particle organic composition and morphology by STXM-NEXAFS. These measurements provided some of the first measurements of organic functional groups in atmospheric particles in the Southern Hemisphere, complementing the sparse existing measurements in Australia, South America, and Africa. The measured organic composition has been analyzed using state-of-the-art microphysical and thermodynamic models. With a one-year supplement, we have verified our measurement techniques with an improved inlet system. This work has contributed to our ongoing collaboration on aerosol-cloud-climate interactions with NOAA investigators. As a result of these measurements, this project has made substantial advances in understanding the composition of marine organic aerosol particles, including a clear quantitative assessment of the contribution of carbohydrates from bubble bursting at the sea surface microlayer. There are 12 peer-reviewed publications that reported important aspects of this finding: preliminary evidence for marine organics in cloud droplets (Hawkins et al., 2008), consistency of multiple measurement techniques for marine organics (Russell et al., 2009), evidence for marine organics at California and Northeastern coastal sites (Bahadur et al., 2010; Hawkins and Russell, 2010a; Liu et al., 2011; Day et al., 2010), identification of marine organic components in the southeastern Pacific as part of VOCALS-REx (Hawkins et al., 2010b), single particle characterization of marine organic particles (Takahama et al., 2010; Hawkins and Russell, 2010b), broad chemical consistency in marine organics in four ocean regions (Russell et al., 2010), influence of ship emissions and other pollution on marine organic aerosol (Frossard et al., 2011), and finally improved quantification of marine organics by identification of hydrate contributions (Frossard and Russell, 2012). The measurements of the Russell group also supported several collaborative studies led by other groups, with six published to date (Allen et al., 2011; Wood et al., 2011; Yang et al., 2011; Lapina et al., 2011; Bates et al., 2012; Shepson et al., 2012). This project provided the opportunity for three graduate students and a postdoc to participate in multinational scientific teams as part of two NOAA field studies, VOCALS-REx and CalNex 2010. The doctorate level students completed thesis research based on VOCALS-REx and related studies, incorporating both their own field measurements and those obtained by collaborators. The rich, scientific environment to which these students were exposed substantially enhanced their PhD studies, with two completing PhD theses and finding postdoctoral (and faculty) positions and the third well on her way to completing her PhD. To this end, the students participated in and contributed to outreach and K-12 educational programs developed for VOCALS-REx, and investigator Russell was lead instructor for the UCSD COSMOS cluster on Global Change.
