Atmospheric 14CO is produced throughout Earth's atmosphere. Subsequent to its formation, 14CO is oxidized to CO2, primarily by OH, or hydroxyl radicals. OH is the primary atmospheric oxidant, and therefore its abundance determines the lifetime of many reduced trace gases, including methane, hydrocarbons, and CO. However, because of its very low abundance, high reactivity and variability, direct measurements of OH are of limited value. To determine spatially and temporally averaged OH abundances, we use 14CO as a tracer.
In collaboration with the National Institute for Water and Atmosphere, New Zealand, and the Max Planck Institute for Chemistry, Mainz, Germany, we have a network of 6 sites where samples are collected on a weekly or biweekly basis. These sites span a latitude range of 77S to 60N. We then use 3-D atmospheric climate models and general circulation models to help interpret our results.
Here we will discuss the general application of 14CO to atmospheric chemistry as well as present recent measurements of 14CO from three field sites, representing a range in latitude: Samoa, Mauna Loa, and The Westmann Islands, Iceland.
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See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)