Collaborative Research: An integrated model-proxy approach to understanding Western US hydroclimate change since the last glacial period

合作研究：了解自末次冰期以来美国西部水文气候变化的综合模型代理方法

• 批准号: 2102956
• 负责人: Rebecca Hatheway
• 金额: $ 4.86万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102956&HistoricalAwards=false
• 关键词: Collaborative; Research; integrated; model; proxy

Understanding what processes drive changes in rainfall along the U.S. West Coast is essential for predicting future water availability in this densely populated and agriculturally productive part of the country. However, given the short duration of direct meteorological observations (~100 years), it is beneficial to reconstruct past changes in rainfall over longer time periods (i.e., thousands of years) in order to uncover the potential sensitivity of water resources in the Western U.S to future climate change. This research project combines measurements of ancient groundwater and state-of-the-art climate model experiments to both quantify and understand the dynamical drivers of hydrological change along the American West Coast during the last ice age (i.e., the Last Glacial Maximum or LGM, ~25,000 years ago). This project also includes a comprehensive public outreach component, involving the creation of a museum exhibit for display at the National Center for Atmospheric Research (NCAR). In collaboration with the University of Colorado Boulder, the researchers will lead an interdisciplinary course for students to design and prototype a museum exhibit that brings to life the radically different atmospheric circulation and rainfall patterns present during the LGM.The first research component of this project involves a field campaign to collect groundwater samples from a network of wells within the Columbia Plateau Aquifer system in northeastern Oregon and southeastern Washington, which will provide a much-needed quantitative constraint on LGM hydroclimate in the data-poor Pacific Northwest. A new analytical technique for high-precision measurements of dissolved noble gas concentrations and Krypton and Xenon isotope ratios within the groundwater will be employed to reconstruct past temperature and regional water table depth. The second research component of the project involves climate model experiments using NCAR’s Community Earth System Model version 1.2 (CESM1) to build upon existing fully equilibrated climate simulations to study the influence of different LGM boundary conditions (ice sheet albedo/topography, greenhouse gases, orbital forcing, etc) on North Pacific atmospheric circulation and the intensity, variability, and landfalling orientation of moisture-rich storms known as Atmospheric Rivers (ARs). The project also includes a series of time-slice experiments, simulating both deglacial and glacial conditions, to examine the transient response of ARs and western North American hydroclimate to shrinking and growing continental ice sheets. Finally, detailed comparisons will be made between these model simulations and the proxy reconstructions of Pacific Northwest water table depths.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.

了解推动美国西海岸降雨量变化的过程对于预测该国人口稠密和农业多产地区未来的可用水量至关重要。然而，鉴于直接气象观测的持续时间较短（约100年），有利于重建较长时间段（即数千年）内的降雨量变化，以揭示美国西部水资源对未来气候变化的潜在敏感性。该研究项目结合了古代地下水的测量和最先进的气候模型实验，以量化和理解上一个冰河时代（即约 25,000 年前的末次盛冰期或 LGM）沿美国西海岸水文变化的动态驱动因素。该项目还包括全面的公共宣传部分，包括创建一个博物馆展览，在国家大气研究中心 (NCAR) 展示。研究人员将与科罗拉多大学博尔德分校合作，开设一门跨学科课程，让学生设计一个博物馆展览并制作原型，以生动地呈现末次盛世时期截然不同的大气环流和降雨模式。该项目的第一个研究部分包括一项实地活动，从俄勒冈州东北部和华盛顿州东南部的哥伦比亚高原含水层系统内的井网收集地下水样本，这将提供 对数据匮乏的太平洋西北地区末次盛冰期水文气候进行急需的定量约束。将采用一种新的分析技术来高精度测量地下水中溶解的惰性气体浓度以及氪和氙同位素比率，以重建过去的温度和区域地下水位深度。该项目的第二个研究部分涉及使用 NCAR 的社区地球系统模型版本 1.2 (CESM1) 进行气候模型实验，以现有完全平衡的气候模拟为基础，研究不同末次盛宴边界条件（冰盖反照率/地形、温室气体、轨道强迫等）对北太平洋大气环流以及被称为大气河的富含水分的风暴的强度、变化和登陆方向的影响 （AR）。该项目还包括一系列时间切片实验，模拟冰消和冰川条件，以研究 AR 和北美西部水文气候对大陆冰盖缩小和增长的瞬态响应。最后，将对这些模型模拟与太平洋西北地区地下水位深度的代理重建进行详细比较。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。