EAGER: A Comparison of Lacustrine Carbonate d18O and Organic Matter dD from Drought Sensitive Lakes in the Western United States

仪器气候记录表明，北美西部的干旱模式对太平洋的可变性以及厄尔尼诺南方涛动和北美季风之间的相互作用很敏感。需要更深入地了解这些模式过去的行为，以改进对未来干旱和暴雨周期的预测。这项拟议的研究将：1)为在没有单相碳酸盐可用于Delta-18氧分析的湖泊系统中使用三角洲-氚记录提供概念证明；2)增加一个不断增长的定量古气候数据集网络，这将为我们理解北美西部的干旱模式和相关的天气气候遥相关提供关键的时空视角。拟议的项目将从百年尺度上从美国西部两个干旱敏感的湖泊中开发两个封闭盆地湖泊的湖泊沉积物有机质del-D记录。第一个是卡斯特湖，这是华盛顿州一个经过充分研究的系统，十年来一直在使用湖面传感器、水温记录仪、沉积物捕集器、气象站以及每年一次的地面、湖泊和溪流采样来检测水化学和稳定同位素。卡斯特湖已经公布了十年尺度的氧同位素记录，这为与藻类Del-D进行比较提供了机会。第二个湖，格雷厄姆湖，也是位于新墨西哥州的干旱敏感系统，新墨西哥州是一个对干旱研究非常感兴趣的地区。该团队访问了这个系统，验证了它符合他们拟议工作的标准，并计划为这项研究恢复一系列重叠的岩芯。更广泛的影响是，如果这种新的del-D技术在这些没有单相碳酸盐的湖泊中成功，产生的来自美国西部的古变形数据集网络将提供有关湿/干循环的时间、持续时间和大小的重要新信息，并结合正在进行的研究，确定北美晚全新世干旱的空间模式。

Instrumental climate records indicate that drought patterns in western North America are sensitive to Pacific Ocean variability and to interactions between the El Niño Southern Oscillation, and the North American monsoon. A deeper understanding of the past behavior of these modes is needed to improve predictions of future drought and pluvial cycles. This proposed research would: 1) provide proof of concept for the use of delta-Deuterium records in lake systems where single phase carbonates are not available for delta-18 Oxygen analyses and 2) add to a growing a network of quantitative paleoclimate data sets that would add a critical spatial and temporal perspective to our understanding of aridity patterns in western North America and associated synoptic climate teleconnections.The proposed project will develop lake sediment organic matter del-D records from two closed-basin lakes at centennial scale from two drought-sensitive lakes in the western US for the last 2,000 years. The first, Castor Lake, is a well-studied system in Washington State that has been instrumented for a decade with lake level sensors, water temperature loggers, sediment traps, a weather station, and annual ground, lake and stream sampling for water chemistry and stable isotopes. A decadal scale record of oxygen isotopes has been published from Castor Lake, and offers an opportunity for comparison with Algal del-D. The second lake, Graham Lake, is also a drought-sensitive system located in New Mexico, a region of great interest for drought studies. The team has visited this system, verified that it meets the criteria for their proposed work and plans to recover a series of overlapping cores for this study.The broader impacts are that if this new del-D technique is successful in these lakes without single phase carbonates, the resulting network of paleodrought datasets from the western US would provide important new information on the timing, duration and magnitude of wet/dry cycles and combined with ongoing research, identify spatial patterns of aridity in North America during late Holocene.