Collaborative Research: Record of the Triple-oxygen Isotope and Hydrogen Isotope Composition of Ice from an Ice Core at South Pole

合作研究：南极冰芯冰的三氧同位素和氢同位素组成记录

• 批准号: 1443328
• 负责人: James White
• 金额: $ 26万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443328&HistoricalAwards=false
• 关键词: Collaborative; Research; Record; Triple; oxygen

This project will develop a record of the stable-isotope ratios of water from an ice core at the South Pole, Antarctica. Water-isotope ratio measurements provide a means to determine variability in temperature through time. South Pole is distinct from most other locations in Antarctica in showing no warming in recent decades, but little is known about temperature variability in this location prior to the installation of weather stations in 1957. The measurements made as part of this project will result in a much longer temperature record, extending at least 40,000 years, aiding our ability to understand what controls Antarctic climate, and improving projections of future Antarctic climate change. Data from this project will be critical to other investigators working on the South Pole ice core, and of general interest to other scientists and the public. Data will be provided rapidly to other investigators and made public as soon as possible.This project will obtain records of the stable-isotope ratios of water on the ice core currently being obtained at South Pole. The core will reach a depth of 1500 m and an age of 40,000 years. The project will use laser spectroscopy to obtain both an ultra-high-resolution record of oxygen 18/16 and deuterium-hydrogen ratios, and a lower-resolution record of oxygen 17/16 ratios. The high-resolution measurements will be used to aid in dating the core, and to provide estimates of isotope diffusion that constrain the process of firn densification. The novel 17/16 measurement provides additional constraints on the isotope fractionation due to the temperature-dependent supersaturation ratio, which affects the fractionation of water during the liquid-solid condensate transition. Together, these techniques will allow for improved accuracy in the use of the water isotope ratios as proxies for ice-sheet temperature, sea-surface temperature, and atmospheric circulation. The result will be a record of decadal through centennial and millennial scale climate change in a climatically distinct region in East Antarctica that has not been previously sampled by deep ice coring. The project will support a graduate student who will be co-advised by faculty at the University of Washington and the University of Colorado, and will be involved in all aspects of the work.

该项目将记录南极洲冰芯中水的稳定同位素比率。水同位素比测量提供了一种确定温度随时间变化的方法。 南极与南极洲大多数其他地点不同，近几十年来没有出现变暖现象，但在 1957 年安装气象站之前，人们对该地点的温度变化知之甚少。作为该项目的一部分进行的测量将得出更长的温度记录，至少延续了 4 万年，有助于我们了解控制南极气候的因素，并改进对未来南极气候变化的预测。该项目的数据对于其他研究南极冰芯的研究人员至关重要，并且引起其他科学家和公众的普遍兴趣。 数据将迅速提供给其他调查人员并尽快公开。该项目将获得目前在南极获得的冰芯上水的稳定同位素比率记录。核心深度将达到1500米，年龄为40,000年。该项目将利用激光光谱获得氧 18/16 和氘氢比的超高分辨率记录，以及氧 17/16 比的较低分辨率记录。高分辨率测量将用于帮助确定岩心的年代，并提供限制冰致密化过程的同位素扩散的估计。由于依赖于温度的过饱和度比率，新颖的 17/16 测量对同位素分馏提供了额外的限制，这会影响液-固冷凝物转变过程中水的分馏。总之，这些技术将提高使用水同位素比作为冰盖温度、海面温度和大气环流代理的准确性。结果将是南极洲东部一个气候独特地区的十年到百年和千年规模的气候变化记录，该地区以前从未通过深冰芯取样。该项目将支持一名研究生，该研究生将得到华盛顿大学和科罗拉多大学教师的共同指导，并将参与工作的各个方面。