CAREER: California Megadroughts in Context: Integrating High Resolution Speleothem Records with Isotope-enabled Climate Models and Translating Climate Data for the K-12 Classroom

该CAREER项目的总体目标是将来自两个加州洞穴的末次冰消期和全新世气候变化的高分辨率、多代理洞穴沉积物记录与同位素支持的古气候模型相结合，以限制降水量和降水来源的变化，并确定加州水文变化的驱动因素，包括严重干旱。 Speleothem记录（即，氧和碳同位素、晶体组构、微量元素、锶和铀同位素）。 一个同位素启用反应运输建模工具将被用来解析环境代理的多个相互关联的环境影响。 这项研究将有助于推进speleothem初始铀同位素比，渗透率的新兴代理，通过关键的气候转变进行高分辨率的测量，并通过调查洞穴滴水铀同位素比的空间和时间变化。本项目中开发的加州中部和北方洞穴沉积记录将与其他区域记录相结合，以创建沿着美国西海岸降水变化的随时间变化的地图。将这些地图与同位素气候模型对末次冰消期和全新世的时间切片进行定量比较，将有助于澄清降水变化和区域气候变率背后的驱动机制。该研究的预期成果包括：1）发展美国西海岸沿着降水变化的历史，包括从多个代理的重叠石笋记录延伸到33，000年前; 2）与同位素激活的反应传输模型的代理和监测数据的交叉验证; 3）评估洞穴沉积物初始铀同位素比值作为古渗透指标; 4）详细记录年际到数十年降水变率，对比现代降水对海洋-大气振荡的响应，并对这些模式随时间的演变进行展望; 5）通过代理模式比较，评估加州降水变率的驱动机制，包括大尺度条件; 6）提高了对水分来源变化在干旱条件发展和衰退中的作用的认识。该教育计划建立在研究人员与范德比尔特大学科学与数学学院（SSMV）的持续关系基础上，一个为期一年的辅导团队的高中学生从大都会纳什维尔公立学校（MNPS）谁将进行现场实验，地球化学研究，并最终创建一个在线教育工具，用于田纳西州的教室。 在线门户网站的目标是以一种对教师有用和可访问的方式在线提供丰富的气候和古气候数据，希望通过使数据驱动的方式改变气候科学在K-12课堂上的教学方式，沉浸式学习更容易实现。该项目将涉及研究生，本科生和高中生生产的教育产品，有可能对田纳西州的科学教室和超越持久的积极影响。

This CAREER project generally aims to integrate high-resolution, multi-proxy speleothem records of climate change during the last deglaciation and Holocene from two California caves with isotope-enabled paleoclimate models in an effort to constrain changes in precipitation amount and source and identify the drivers of hydrologic change in California, including severe drought. Speleothem records (i.e., oxygen and carbon isotopes, crystal fabrics, trace elements, strontium and uranium isotopes) will be developed from cave monitoring. An isotope-enabled reactive transport modeling tool will be used to parse the multiple interrelated environmental influences on environmental proxies. This research will help advance speleothem initial uranium isotope ratios, an emerging proxy for infiltration rate, by conducting high-resolution measurements through key climatic transitions and by investigating the spatial and temporal variability of Uranium isotope ratios in cave drip water. Central and northern California speleothem records developed in this project will be integrated with other regional records to create time-varying maps of precipitation change along the U.S. west coast. Quantitative comparison of these maps with isotope-enabled climate models for time slices through the last deglaciation and Holocene will help clarify the driving mechanisms behind precipitation change and regional climate variability. Expected outcomes of the research include: 1) development of a history of precipitation variability along the U.S. west coast consisting of overlapping stalagmite records from multiple proxies for extending to 33,000 years before the present; 2) cross-validation of proxy and monitoring data with isotope-enabled reactive transport models 3) evaluation of speleothem initial Uranium isotope ratios as a paleo-infiltration indicator; 4) detailed records of inter-annual to multi-decadal precipitation variability at sites with contrasting modern precipitation responses to ocean-atmosphere oscillations and perspective on the evolution of these patterns through time; 5) evaluation of the driving mechanisms of California precipitation variability, including megadrought conditions, through proxy-model comparisons; and 6) improved understanding of the role of changing moisture source in the development and decay of drought conditions.The education plan builds on the researcher's ongoing relationship with the School for Science and Math at Vanderbilt University (SSMV) through multi-year mentoring of a team of high school students from the Metropolitan Nashville Public Schools (MNPS) who will conduct field experiments, geochemical research, and ultimately, the creation of an online educational tool for use in Tennessee classrooms. The goal of the online portal is to present the wealth of climate and paleoclimate data available online in a way that is useful and accessible for teachers, with the hope of transforming the way climate science is taught in K-12 classrooms by making data-driven, immersive learning on this topic more achievable. This project will involve graduate, undergraduates, and high school students to produce an educational product that has the potential for a lasting positive influence on Tennessee science classrooms and beyond.