Date of Award

Winter 2007

Project Type

Thesis

Program or Major

Earth Sciences

Degree Name

Master of Science

Abstract

The sources, sinks, and overall importance of water-soluble organic carbon (WSOC) in the atmosphere are not well understood. To better address this lack of knowledge, measurements of WSOC in both the gas (WSOC G) and particulate WSOCP phases were made using a newly developed technique during five research campaigns. Part 1 of this thesis investigates atmospheric and firn-air WSOC related to the post-depositional processing of organic compounds within Arctic snow during a research campaign at Summit, Greenland. Part 2 of this thesis highlights the discovery that at all locations where data were collected, WSOCG concentrations are significantly larger than those of WSOCP.

A clear and consistent result from all five research campaigns is that WSOCG concentrations are significantly larger than those of WSOC P. The average values of the fractions of WSOCG compared to the total WSOC (fg) for the five campaigns ranged from 0.64 to 0.93. This variation in fg implies that significant differences in WSOC phase partitioning exist between locations, despite the consistent predominance of WSOCG. During the two longest campaigns, in Houston, Texas, and Summit, Greenland, a similar, repeatable diurnal pattern was observed with minimum values for fg occurring at night. This behavior is attributed, at least in part, to temperature related gas-to-particle partitioning. These trends suggest that the measured WSOCG and WSOCP are related and potentially comprised of similar groups of organic species, at least at certain times. This finding and observed fg values greater than 0.5 indicate that a large amount of organic material that participates in aerosol processes is not taken into account by aerosol measurements alone.

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