Methane Isotope Variations Covering the Holocene from the WAIS Divide Core

WAIS 分核核心覆盖全新世的甲烷同位素变化

• 批准号: 0944584
• 负责人: Todd Sowers
• 金额: $ 25.11万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944584&HistoricalAwards=false
• 关键词: Methane; Isotope; Variations; Covering; Holocene

Sowers 0944584This award supports a project to better predict how natural CH4 emissions will respond to and force future climate change through a detailed study of the global biogeochemical cycles that control atmospheric CH4 over the past 11,000 years (11kyr), when the Earth's climate has remained relatively close to its current state. During that time, methane concentrations changed significantly. The project involves generating 13C/12C isotopic records of atmospheric CH4 using the core material from the WAIS Divide ice core. The ä13CH4 data from WAIS will be used to construct the first Antarctic atmospheric record covering the Holocene. This record will be compared to our recent Holocene record from the GISP2 ice core from Greenland. The new Antarctic record will provide an important verification of the GISP2 record as well as our first glimpse of the inter-hemispheric ä13CH4 gradient covering the Holocene. Together these records provide important boundary conditions for testing various emission scenarios (time, space and source) that should provide a quantitative basis for assessing the nature of CH4 emissions throughout the Holocene. The intellectual merit of this work relates to the fact that the earth's climate is directly influenced by levels of trace, "greenhouse" gases (carbon dioxide, methane, nitrous oxide, CFC's, and others), and the modern build up of these gases in the atmosphere is a fundamental concern for human society. In terms of broader impacts the proposed work will enhance our understanding of the patterns and causes of methane change throughout the Holocene. This is important for understanding the natural climate system, and in particular, feedbacks between climate and greenhouse gas biogeochemistry. The Holocene CH4 record suggests that the global methane cycle was profoundly influenced by various feedbacks that do not involve large temperature swings. This implies strong feedbacks to a relatively small (and presently unknown) forcing. The proposed work will lead to improved understanding of why methane levels changed throughout the Holocene, providing fundamental information to refine and test global models. It will also contribute to testing the controversial, but important, hypothesis, that humans impacted the atmosphere significantly starting about 5000 years ago. Undergraduate and graduate students will participate in all phases of the research and a special emphasis will be placed on recruiting under represented minority students thru our college based office of educational equity. All data will be archived on appropriate databases per OPP policies.

Sowers 0944584该奖项支持一个项目，通过对过去 11,000 年 (11kyr) 控制大气 CH4 的全球生物地球化学循环进行详细研究，更好地预测自然 CH4 排放将如何响应并迫使未来的气候变化，当时地球气候保持相对稳定在此期间，甲烷浓度发生了显着变化，该项目涉及使用核心生成大气 CH4 的 13C/12C 同位素记录。来自 WAIS Divide 冰芯的 ä13CH4 数据将用于构建第一个覆盖全新世的南极大气记录，该记录将与我们最近来自格陵兰岛的 GISP2 冰芯的全新世记录进行比较。提供了对 GISP2 记录的重要验证，以及我们对覆盖全新世的半球间 ä13CH4 梯度的首次了解，这些记录共同为测试各种参数提供了重要的边界条件。排放情景（时间、空间和来源）应为评估整个全新世 CH4 排放的性质提供定量基础。这项工作的智力价值与地球气候直接受到痕量“温室气体”水平的影响有关。 “气体（二氧化碳、甲烷、一氧化二氮、氟氯化碳等），以及这些气体在大气中的现代积累是人类社会的一个基本问题。就更广泛的影响而言，拟议的工作将增强我们对这些气体的理解图案与图案这对于理解自然气候系统，特别是气候与温室气体生物地球化学之间的反馈非常重要。全新世 CH4 记录表明，全球甲烷循环受到不涉及的反馈因素的深刻影响。这意味着对相对较小（目前未知）的强迫的强烈反馈将有助于更好地理解为什么整个全新世甲烷水平发生变化，为完善和测试全球提供基础信息。它还将有助于测试有争议但重要的假设，即人类从大约 5000 年前开始就对大气产生了重大影响，本科生和研究生将参与该研究的所有阶段，并将特别重视招募学生。通过我们大学教育公平办公室代表少数族裔学生，所有数据都将根据 OPP 政策存档在适当的数据库中。