A Model-Data Approach to Better Understand Paleoclimate Records of Stable Water Isotopes in High-Elevation, Lower-Latitude Glaciers

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This project generally aims to develop a framework using modeling approaches to interpret climate variability from ice core delta Oxygen-18 in low-latitude and tropical glaciers. Specifically, the researchers will examine water isotopes not only in surface precipitation, but also in relationship with the vapor delta Oxygen-18 throughout the atmospheric column. The key regions of investigation are the tropical Andes and northwestern Tibetan Plateau where isotopic observations of ice from the tropical Andes are presumed a proxy for atmospheric temperature while the Tibetan Plateau evidences a mixture of temperature and precipitation signals.Vapor delta oxygen-18 is studied and used most extensively to represent temperature variability in the polar regions or precipitation variability in cave speleothems in low-land tropical monsoon regions. Its climatic interpretation in ice cores from mid-latitude and tropical mountain glaciers, however, is more poorly understood, raising a question for the paleoclimate community: Is vapor delta oxygen-18 from ice cores recovered from tropical and mid-latitude glaciers a proxy for temperature or precipitation?Furthermore, to facilitate comparisons of ice core records and simultaneously reduce model bias due to unrealistically low model topography, the researchers will perform high-resolution model experiments with model topography elevated to the actual altitude of the ice cores. The goal of the model-data integration exercise is to improve understanding of how to interpret climate variability from ice core delta Oxygen-18 precipitation in low-latitude and tropical glaciers.The potential Broader Impacts include support of a post-doctoral scholar and doctoral student, annual outreach activities to the public through the Byrd Polar Climate Research Center, and, importantly, addressing a knotty climate science interpretation issue.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.