Funding is provided to test the hypothesis that the oxygen isotopic composition of sulfate in ice cores can provide quantitative information on atmospheric oxidant concentrations for past climates. Specifically, the researchers will use a global chemical transport model, GEOS-Chem, to perform a series of model simulations to examine the global sensitivity of sulfate oxygen isotopes to changing climatic conditions and atmospheric oxidant concentrations on glacial-interglacial timescales. The researchers will drive their chemistry model by meteorology calculated by a general circulation model, GISS ModelE, and a global vegetation model, BIOME4-TG.
The overall scientific goal of the research is to conduct an analysis, using ice cores, of the sensitivity of sulfate oxygen isotopes to changes in oxidant concentrations and climate on glacial-interglacial timescales. Successful calibration of paleo OH concentrations might aid efforts to constrain the past budgets of species such as methane (CH4) whose lifetimes depend on the magnitude of the OH sink reaction. This could consequently help to improve the wider science community's understanding of methane in climate as well as the interaction of oxidants in the atmosphere over time.
