Collaborative Research: REU: Calibrating the Water Isotope Thermometer in Antarctica Using Abrupt Heinrich Event Signatures in the EDML Ice Core

合作研究：REU：利用 EDML 冰芯中的突变海因里希事件特征校准南极洲的水同位素温度计

• 批准号: 2315927
• 负责人: Jeffrey Severinghaus
• 金额: $ 52.28万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2315927&HistoricalAwards=false
• 关键词: Collaborative; Research; REU; Calibrating; Water

This project seeks to answer the question, "How cold was Antarctica during the last ice age?" This information will help to predict the magnitude of future warming in Antarctica due to human emissions of heat-trapping gases, with implications for the stability of Antarctic ice sheets and sea level in the next 50 to 100 years. The proposed method uses a new "gas thermometer" based on air trapped in snow and preserved as air bubbles in ice that can be recovered from ice cores. The new thermometer uses ratios of nitrogen and argon isotopes (an isotope of a given element has a different number of neutrons) from the air bubbles in the ice and has been used successfully in Greenland over the past two decades to show that Greenland temperatures during the last ice age were ~35 degrees Fahrenheit colder than at present. Antarctica is more challenging to study than Greenland, but recent improvements in the gas thermometer now make it practical to address Antarctica's temperature history and inform its future under human influence. This project will train graduate and undergraduate students in these methods.The classical method for obtaining past temperatures on polar ice sheets uses the isotopes of water (18O and 2H) and has been shown to suffer from biases, for example underestimating Greenland cooling in the Last Glacial Maximum by a factor of 2. This project seeks to calibrate the water-isotope thermometer in East Antarctica using the recently improved inert-gas thermometer based on isotopes of N2 and Ar. The project will use ice from a core from East Antarctica (Dronning Maud Land) in collaboration with European colleagues. Further, ice samples of the same age from a West Antarctic ice core will be measured as a benchmark. The project will also perform targeted measurements of methane and N2 isotopes along the length of the East Antarctic ice core, to better understand the climate history and firn evolution of the core. These measurements will enable a second, independent calibration of the water-isotope thermometer from the observed gas-age – ice-age difference along the East Antarctic core.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.

该项目试图回答一个问题：“上一个冰河时代的南极洲有多冷？”由于人类的热吸收气体排放，该信息将有助于预测南极洲未来变暖的大小，这对未来50至100年内南极冰盖和海平面的稳定性产生了影响。提出的方法基于被困在雪中的空气并将气泡保存在冰中的空气中，使用了一种新的“气体温度计”，可以从冰芯中回收。新温度计使用氮和氩同位素（给定元件的同位素具有不同数量中子的同位素）的比率与冰中的气泡不同，并且在过去二十年中在格陵兰岛已成功使用，以表明在上一个冰河时代的格陵兰温度约为35摄氏度fahrenheit Colder。与格陵兰相比，南极研究更具挑战性，但是现在气体温度计的最新改善使得解决南极的温度病史并在人类影响下为其未来提供了信息。该项目将以这些方法培训毕业生和本科生。用于在极性冰盖上获得过去温度的经典方法使用水的同位素（18O和2H），并且已显示出偏见的障碍，例如低估了格陵兰岛在最后一个冰川中最大值的格陵兰式冷却2。该项目基于2的最大值。该项目可用于校准，以校准型号的水上蚂蚁，以校准水上蚂蚁的范围，以校准水上蚂蚁，以校准水上蚂蚁静水电仪，以供应量为“水”，这是在水上镇定的，以东蚂蚁的水平升温。 N2和AR的同位素。该项目将与欧洲同事合作使用来自东南极（Dronning Maud Land）的核心的ICE。此外，来自南极冰芯的同一年龄的冰样将作为基准测量。该项目还将在南极冰芯的长度沿甲烷和N2同位素进行靶向测量，以更好地了解核心的气候历史和首次演变。这些测量值将实现第二个独立的校准，从观察到的气流 - 沿东极核心的冰河时代差异对水 - 同位素温度计进行了独立的校准。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛影响的审查标准通过评估来评估的。