Collaborative Research: P2C2--Paleoaridity Shifts in a Regional Climatological Hotspot During Abrupt Global Change Events: An Observation-Model Approach

合作研究：P2C2——全球突变事件期间区域气候热点的古干旱变化：观测模型方法

• 批准号: 2203053
• 负责人: Sylvia Dee
• 金额: $ 7.32万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203053&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Paleoaridity; Shifts

The general research goal of the research is to evaluate the modern hydroclimate in central Texas that is currently dominated by moisture delivered from the Gulf of Mexico (GoM), tropical Atlantic, and continental recycling, with smaller components from the Pacific. The Great Plains Low-Level Jet generates rainfall while atmospheric conditions govern how much rainwater evaporates, setting the geospatial distribution of aridity. This project will specifically test the hypothesis that this regional distribution of aridity has shifted in terms of both location and intensity as a function of past abrupt global warming and cooling events.The researchers aim to reconstruct speleothem (cave deposits) proxy records from central Texas during episodes of known rapid global change between the last 16,000 years to 11,000 years– spanning the Bølling- Allerød (BA) and Younger Dryas (YD) using existing samples from caves across the Edwards Plateau in central Texas. These caves have been monitored and assessed relative to modern climate parameters, thereby helping to maximize the information from the proxy records. The research team will analyze seven coeval speleothems spanning a 375-kilometer West to East transect, constructing high-resolution oxygen isotope and growth rate proxy records constrained by high-precision Uranium-Thorium chronologies. The resulting speleothem records will be analyzed as a function of longitude to discern changes in moisture source, as well as the steepness and location of the wet-dry gradient. The research approach will: 1) employ proxy system models (PSMs) to assess the influence of cave-specific speleothem growth parameters such as carbon dioxide transport, temperature, water transport and drip rates, and source delta Oxygen-18 isotopes; 2) integrate isotopic variations and growth rates to enhance reconstructions of paleo-aridity; 3) develop proxy time series to ground-truth isotope-enabled general circulation models; and 4) use models to test the regional sensitivities to climate forcing mechanisms, including insolation, greenhouse gases, ice sheet dynamics, and meltwater input to the GoM. Proxy-model comparison will be employed to inform regional circulation dynamics during abrupt change events.This research is important because the climate of the eastern United States is becoming wetter while the western United States is drying. The continental wet-dry line has been shifting eastward over the past four decades and could ultimately degrade water security for millions of citizens in Texas residing in the rapidly growing urban corridor stretching from the Rio Grande Valley to the Dallas-Fort Worth region. This project seeks to understand the mechanisms by which warming and cooling influence aridity in this region to refine and inform projections under a range of future climate scenarios.The potential Broader Impacts include greater understanding of water resources in the western United States, support for a doctoral graduate student, and outreach.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.

该研究的总体研究目标是评估德克萨斯州中部的现代水文气候，目前该地区的水分主要来自墨西哥湾 (GoM)、热带大西洋和大陆循环，还有少量来自太平洋的大平原低气压。 -水平急流产生降雨，而大气条件控制雨水蒸发量，从而确定干旱的地理空间分布。该项目将专门测试这一假设，即干旱的区域分布在位置和强度方面都随着过去的变化而发生了变化。全球突然变暖和变冷事件。研究人员的目标是重建德克萨斯州中部在过去 16,000 年至 11,000 年间已知的快速全球变化期间的洞穴沉积物（洞穴沉积物）代理记录，跨越伯林-阿勒罗德 (BA) 和新仙女木期 (BA)。 YD）使用德克萨斯州中部爱德华兹高原洞穴的现有样本，根据现代气候参数对这些洞穴进行了监测和评估，从而有助于最大限度地利用来自德克萨斯州中部爱德华兹高原洞穴的现有样本。研究小组将分析横跨 375 公里从西到东横断面的七个同时期洞穴，构建受高精度铀-钍年代学约束的高分辨率氧同位素和生长率代理记录。由此产生的洞穴记录将被分析为：经度的函数来识别水分源的变化以及干湿梯度的陡度和位置。研究方法将：1）采用代理系统模型。 (PSM) 评估洞穴特定洞穴生长参数的影响，例如二氧化碳输送、温度、水输送和滴水率以及来源 δ 氧 18 同位素；2) 整合同位素变化和生长率，以增强古生物的重建干旱；3) 开发基于同位素的大气环流模型的代理时间序列；4) 使用模型测试区域对气候强迫机制的敏感性，包括日照、温室气体、冰盖动力学和融化水输入到 GoM 的比较将用于了解突变事件期间的区域环流动态。这项研究很重要，因为美国东部的气候正在变得更加湿润，而美国东部的气候正在变得更加湿润。美国西部正在干燥。过去四十年来，大陆干湿线一直在向东移动，最终可能会降低居住在从里奥格兰德河谷延伸到达拉斯的快速增长的城市走廊中的数百万德克萨斯州居民的水安全。沃斯堡该项目旨在了解变暖和变冷影响该地区干旱的机制，以便在一系列未来气候情景下完善预测并为预测提供信息。潜在的更广泛影响包括更好地了解美国西部的水资源、支持该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。