P2C2: A Hydrogen Isotopic Approach to Resolving Precipitation Seasonality: Application to East Asian Speleothem Oxygen Isotopes

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This project explores using the hydrogen and oxygen isotopic composition of precipitation as a proxy for climate reconstructions from Chinese cave deposits. The primary goal of the research is to develop proxies for monitoring seasonality in hydrologic cycles.The guiding research principle is that cave speleothem delta Oxygen-18 records the weighted annual average isotopic composition of precipitation making it to the cave whereas the delta Deuterium of leaf wax monitors the growing season (typically summer) isotopic composition of precipitation. The research plan is guided by the hypothesis that the delta Deuterium of leaf wax will have a phase response consistent with summer-monsoon records from India and East Asia and that the winter signal will have a phase consistent with the combined effects of northern hemisphere winter solar insolation minima and ice volume maxima.The primary broader impacts involve support for an underrepresented minority student, collaboration among U.S. and Chinese scientists, and a scientific focus on water resource issues in a water-stressed region that carries important social benefits.