EAR-PF: Quantifying evaporation in Mono Basin: Bridging the gap between hydrologic modeling and paleoclimate records using triple oxygen and clumped isotope geochemistry

EAR-PF：量化莫诺盆地的蒸发：利用三重氧和聚集同位素地球化学弥合水文模型和古气候记录之间的差距

• 批准号: 2204433
• 负责人: Anne Fetrow
• 金额: $ 18万
• 依托单位: Fetrow, Anne C
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204433&HistoricalAwards=false
• 关键词: EAR; PF; Quantifying; evaporation; Mono

Freshwater in the Western United States will become an increasingly precious resource and its allocation will become even more contentious as climate change accelerates and human populations expand. To be able to assist the policymakers and communities who are making water resource management decisions, we must be able to more accurately predict how freshwater resources in watersheds will fluctuate in the future. The Mono Basin watershed in eastern California is one of the main water sources for approximately 11 million people in Los Angeles and presents an important example of the need for timely and science-informed water management strategies. This project aims to improve our understanding of a critical, but commonly poorly constrained, aspect of the Mono Basin hydrologic system: the amount of water lost due to evaporation from its iconic terminal lake, Mono Lake. Misestimation of water lost to evaporation can lead to the over-allocation of existing and future water resources. This project will combine powerful geochemical and hydrologic modeling tools to better quantify evaporation in the Mono Lake watershed and extend our understanding of the variability of regional hydrology and climate in recent history. This research will provide urgently needed information to inform water allocation and conservation decisions and improve the understanding of how critical Sierra Nevadan water resources have been affected by human activity and will likely vary in the future due to the changing global climate. The research team will work closely with the outreach and education staff of the Mono Lake Committee, a key conservation group in the region, to develop citizen-science sampling opportunities and Mono Basin-focused curriculum modules for 6-12th graders to increase community engagement in issues of water resource management and build a stronger understanding of the important role that hydroclimate research can play in policy decisions. While hydrologic mass balance modeling provides a powerful tool in estimating hydrologic variability of critical watersheds, there are key parameters that remain poorly constrained, such as amount of water lost to evaporation. The lack of an accurate estimate of evaporative water loss from major reservoirs creates large uncertainties for hydrologic models and hinders the accuracy of predicting future variability of important water resources. In the face of climate change, Mono Lake and its surrounding watershed in eastern California are emblematic of the increasingly serious issues of water management and conservation. This project aims to address the need for a more accurate estimate of modern and historic evaporative water loss in Mono Basin by combining triple oxygen isotope geochemistry, hydrologic mass balance modeling, and in-situ weather and environmental (e.g., temperature, relative humidity) data collection. The first objective of this study is to quantify the spatial and temporal variability of isotopic composition of various water reservoirs in the modern Mono Basin. These isotope datasets will be then used to assess the accuracy of an isotopically enabled mass balance model in predicting the evaporative water loss from Mono Lake and evolution of water isotope compositions in the basin. Additionally, this project aims to understand how the effects of weather and environmental conditions, known from ~100 years of historic instrumental data, are recorded in the Mono Lake sediment record through the generation of stable isotope proxy data from carbonate-rich sediments. From these lake sediment records, it will be possible to estimate the amount of evaporation and lake water temperature of Mono Lake varied in the last ~500 years. An anticipated outcome of this research is improvement of model simulations of future hydroclimate scenarios for the Sierra Nevada region and our understanding of how stable isotope proxies capture climate signals from arid basins. Additionally, the project will provide an interpretive framework for hydroclimate signals in lacustrine sediment records for use in climate modeling, paleoclimate, and paleoecology studies.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.

美国西部的淡水将成为越来越宝贵的资源，随着气候变化的加速和人口的增长，淡水的分配将变得更加有争议。为了能够协助决策者和社区做出水资源管理决策，我们必须能够更准确地预测流域淡水资源未来将如何波动。加利福尼亚州东部的莫诺盆地流域是洛杉矶约 1100 万人的主要水源之一，也是需要及时、科学的水管理策略的一个重要例子。该项目旨在提高我们对莫诺盆地水文系统一个关键但通常缺乏约束的方面的了解：由于其标志性终端湖莫诺湖蒸发而损失的水量。对蒸发损失水量的错误估计可能导致现有和未来水资源的过度分配。该项目将结合强大的地球化学和水文建模工具，以更好地量化莫诺湖流域的蒸发，并扩展我们对近代历史中区域水文和气候变化的理解。这项研究将提供迫切需要的信息，为水分配和保护决策提供信息，并提高对内华达山脉重要水资源如何受到人类活动影响以及未来可能因全球气候变化而发生变化的了解。研究团队将与莫诺湖委员会（该地区的一个重要保护组织）的外展和教育人员密切合作，为 6-12 年级学生开发公民科学采样机会和以莫诺盆地为重点的课程模块，以提高社区参与度水资源管理问题，并加深对水文气候研究在政策决策中可以发挥的重要作用的理解。虽然水文质量平衡模型为估计关键流域的水文变异性提供了强大的工具，但仍有一些关键参数约束不佳，例如蒸发损失的水量。缺乏对主要水库蒸发水损失的准确估计，给水文模型带来了很大的不确定性，并阻碍了预测重要水资源未来变化的准确性。面对气候变化，加利福尼亚州东部的莫诺湖及其周边流域象征着日益严重的水资源管理和保护问题。该项目旨在通过结合三氧同位素地球化学、水文质量平衡模型以及现场天气和环境（例如温度、相对湿度）数据，满足对莫诺盆地现代和历史蒸发水损失进行更准确估计的需求收藏。这项研究的第一个目标是量化现代莫诺盆地各种水库同位素组成的时空变化。然后，这些同位素数据集将用于评估同位素质量平衡模型在预测莫诺湖蒸发水损失和盆地中水同位素组成演化方面的准确性。此外，该项目旨在了解如何通过从富含碳酸盐的沉积物中生成稳定同位素代理数据，将从大约 100 年的历史仪器数据中得知的天气和环境条件的影响记录在莫诺湖沉积物记录中。根据这些湖泊沉积物记录，可以估计莫诺湖在过去约 500 年中的蒸发量和湖水温度的变化。这项研究的预期成果是改进内华达山脉地区未来水文气候情景的模型模拟，以及我们对稳定同位素代理如何从干旱盆地捕获气候信号的理解。此外，该项目将为湖泊沉积物记录中的水文气候信号提供一个解释框架，用于气候建模、古气候和古生态学研究。该奖项反映了 NSF 的法定使命，并通过利用基金会的智力优势和更广泛的评估进行评估，被认为值得支持。影响审查标准。