Sierra Dabby L&S Math & Physical Sciences
Anomalous Oxygen-Mass Independent Fractionation in Ozone Formation
Ozone formation is accompanied by anomalous oxygen isotope effects. Oxygen has three stable isotopes: 16O, 17O, and 18O (relative abundances of 99.76%, 0.04% and 0.20% with 17O and 18O discovered at Berkeley by Nobel Laureate William Giauque). Isotope geochemists measure these stable isotopes as ratios, 17O/16O or 18O/16O, which have a relationship with slope ~0.5. However, in ozone (O3) formation, the resulting ozone is equally enriched in 17O and 18O relative to 16O and the 17O/16O vs 18O/16O relationship has a slope of 1. This is dubbed mass-independent fractionation (O-MIF). In the stratosphere, ozone can photochemically transfer its O-MIF to carbon dioxide (CO2). However, there are large differences between the 17O/18O slope in stratospheric CO2, in the laboratory when CO2 is exposed to ozone, and in different stratospheric regions. My research will probe a hypothesized temperature dependence of O-MIF transfer from ozone to CO2 using a novel measurement system. The O-MIF in CO2 forms the basis for many tracers of past climates for which knowing the magnitude of the temperature dependence of the O-MIF is critical.
Message To Sponsor
Thank you so much for supporting my research at Berkeley this summer! Being an undergraduate researcher has been critical to my intellectual experience and has let me expand on the topics I’ve explored in my coursework. Research has let me find niches in atmospheric science that I’m passionate about, and I'm excited to explore these further in a planned PhD program.