The chemistry of today's remote, clean atmosphere is largley dominated by the interaction of a few species: methane, carbon monoxide, and hydroxyl radical (which in turn is largely controlled by water vapor and sunlight). This is particularly true in the Southern Hemisphere. The minor isotopes of trace gases provide information on relative strength of various sources. C180 concentrations in particular reflect the relative importance of combustion sources as compared to hydrocarbon oxidation (e.g., methane derived CO). In this seminar I will discuss the general application of trace gas isotopes to atmospheric and paleoatmospheric chemistry, using carbon monoxide as an example. Using both observations and modeling studies, I will present our most recent observations of the minor isotopes 13CO and C180 from air trapped in Antarctic ice cores, and how we can reconstruct the variation in CO relative source strengths over the last several hundred years.
Dr. John Mak is an Associate Professor in the Institute of Terrestrial and Planetary Atmospheres at the School of Marine and Atmospheric Sciences, Stony Brook University, and the Program Director of the Atmospheric Chemistry Program of the National Science Foundation. His research focuses on stable and radioisotopes as tracers of chemistry, origin, and transport in marine and atmospheric environments. Dr. Mak joined Stony Brook University in 1995 after working for two years as a Department of Energy Global Change Distinguished Postdoctoral Fellow at Lawrence Livermore National Laboratory. He received his Ph.D. in Oceanography from the University of California at San Diego in 1992 and his B.S. in Chemistry from the University of California at Irvine.