EAGER: Documenting the Spatial Pattern of Drought in Western North America During the Holocene

EAGER：记录全新世期间北美西部干旱的空间模式

• 批准号: 1252874
• 负责人: Mark Abbott
• 金额: $ 5.41万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1252874&HistoricalAwards=false
• 关键词: EAGER; Documenting; Spatial; Pattern; Drought

Drought in western North America impacts the environment and economy by limiting water for municipalities, agriculture, forestry, hydropower, fisheries and recreational uses. The problem of limited water resources will be compounded by rapid population growth in the western U.S. and the loss of alpine snowpack and glaciers. This problem will be especially difficult in the southern reaches of this region, where alpine snowpack currently buffers stream flow during the summer dry season. Documenting the timing, magnitude, duration and geographic pattern of past wet and dry cycles is an important step toward understanding the causes of droughts. This research will help scientists understand the frequency, duration and magnitude of wet and dry cycles, help place the current drought impacting the region in perspective, and aid policy makers so that they can make better-informed plans regarding water resources. This EAGER grant will use Holocene lake sediment records from British Columbia to reconstruct the spatial and temporal patterns of drought and pluvial cycles along the cordillera of western North America and help identify the underlying causes of these events. The goal is to reconstruct two quantitative Holocene paleoprecipitation records using consistent multiproxy methods, and to compare the results to ongoing work on similar lakes in the western cordillera of North America. The proposed locations in central and northern British Columbia contain numerous lakes with geological and limnological characteristics similar to lakes previously studied in Washington, Oregon, Montana, and the Yukon Territory. The scientists will develop well-dated stable isotope data series from lakes that produce and preserve authigenic calcium carbonate. This carbonate records the oxygen isotope signal of lake water over time, which reflects the frequency and duration of droughts. This data will then be used in climate models to: (i) quantitatively interpret existing proxy data, (ii) identify and rank the factors that influence the frequency and intensity of aridity patterns such as synoptic teleconnections involving both El Niño Southern Oscillation-tropical Pacific climate dynamics and the Atlantic Meridional Overturning Circulation, and most importantly, (iii) reduce the uncertainty in probabilistic forecasts of future drought pattern responses to anthropogenic forcing.

北美西部的干旱限制了市政、农业、林业、水电、渔业和娱乐用途的用水，从而影响环境和经济。美国西部人口的快速增长以及高山积雪和冰川的消失将加剧水资源有限的问题。这个问题在该地区的南部地区尤其困难，因为那里的高山积雪目前在夏季旱季缓冲了溪流。记录过去干湿循环的时间、强度、持续时间和地理模式是了解干旱原因的重要一步。 这项研究将帮助科学家了解干湿循环的频率、持续时间和强度，帮助正确看待当前干旱对该地区的影响，并帮助政策制定者制定更明智的水资源计划。 这项 EAGER 赠款将利用不列颠哥伦比亚省的全新世湖泊沉积物记录来重建北美西部山脉沿线干旱和雨季循环的时空模式，并帮助确定这些事件的根本原因。目标是使用一致的多代理方法重建两个定量全新世古降水记录，并将结果与​​北美西部山脉类似湖泊正在进行的工作进行比较。不列颠哥伦比亚省中部和北部的拟议地点包含许多湖泊，其地质和湖泊学特征与之前在华盛顿、俄勒冈、蒙大拿和育空地区研究的湖泊相似。 科学家们将从产生和保存自生碳酸钙的湖泊中开发出过时的稳定同位素数据系列。这种碳酸盐记录了湖水随时间变化的氧同位素信号，反映了干旱的频率和持续时间。然后，这些数据将用于气候模型：（i）定量解释现有的代理数据，（ii）确定影响干旱模式频率和强度的因素并对其进行排序，例如涉及厄尔尼诺南方涛动-热带太平洋气候动力学和大西洋经向翻转环流的天气遥相关，最重要的是，（iii）减少未来概率预测的不确定性 干旱模式对人为强迫的反应。