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

该项目的总体目标是开发一个框架，使用建模方法来解释低纬度和热带冰川冰芯三角洲氧-18的气候变率。 具体来说，研究人员不仅将研究地表降水中的水同位素，还将研究水同位素与整个大气柱中的蒸汽δ氧-18的关系。研究的重点地区是热带安第斯山脉和青藏高原西北部，其中热带安第斯山脉的冰同位素观测被认为是大气温度的代用指标，而青藏高原则证明了温度和降水信号的混合。陆地热带季风区。 然而，它在中纬度和热带山地冰川冰芯中的气候解释却知之甚少，这给古气候界提出了一个问题：从热带和中纬度冰川中回收的冰芯中的蒸汽三角洲氧-18是温度或降水的代理吗？此外，为了便于冰芯记录的比较，同时减少由于不切实际的低模型地形造成的模型偏差，研究人员将进行高分辨率模型实验，模型地形升高到冰芯的实际高度。模型-数据整合工作的目标是提高对如何从低纬度和热带冰川的冰芯三角洲氧-18降水解释气候变率的理解。潜在的更广泛影响包括对博士后学者和博士生的支持，通过伯德极地气候研究中心向公众开展年度外联活动，重要的是，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.