Atmospheric H2 in the Northern Hemisphere over the past Millennium

过去千年北半球大气 H2

• 批准号: 2243540
• 负责人: Eric Saltzman
• 金额: $ 81.47万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard 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=2243540&HistoricalAwards=false
• 关键词: Atmospheric; H2; Northern; Hemisphere; over

This project will analyze molecular hydrogen (H2) in an ice core from Summit, Greenland to reconstruct atmospheric changes in H2 over the past millennium. This will be the first record of past atmospheric H2 prior to the onset of the industrial era. The results will reveal the natural variability in paleo-atmospheric H2 and how it relates to climate change. The resulting data will provide a baseline for assessing how human activities have influenced atmospheric H2 since the preindustrial era. The results of this study will inform global assessments of how the future hydrogen economy will affect atmospheric composition and climate. The project will provide training for a postdoctoral scholar and undergraduate students.The research involves drilling a new ice core at Summit, extracting air from the samples in the field, with subsequent analysis for H2, Ne, and CH4. Paleo-atmospheric levels of H2 will be inferred from the observed H2/Ne ratio to account for pore close-off fractionation during firn air entrapment and possible gas loss during drilling/sampling. This study will generate the first millennial scale atmospheric history of H2 and examine centennial scale variability associated with the Medieval Climate Anomaly and Little Ice Age. Climate-related variability in H2 is expected because the major loss mechanism is microbial uptake in soil, a process that is highly sensitive to hydrological conditions. The Summit paleo-atmospheric H2 record will therefore provide new constraints on our understanding of the global biogeochemical cycling of H2 and an important test for global models used to assess the climate sensitivity of future H2 emissions.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.

该项目将分析格陵兰萨米特冰芯中的分子氢（H2），以重建过去一千年中H2的大气变化。这将是在工业时代开始之前对过去大气中H2的第一次记录。研究结果将揭示古大气H2的自然变化及其与气候变化的关系。由此产生的数据将为评估自工业化前时代以来人类活动如何影响大气中的H2提供基线。这项研究的结果将为全球评估未来氢经济将如何影响大气成分和气候提供信息。该项目将为博士后学者和本科生提供培训。研究包括在Summit钻取新的冰芯，从现场样品中提取空气，随后分析H2，Ne和CH 4。古大气水平的H2将推断从所观察到的H2/Ne的比例，以占孔隙封闭分馏过程中的积雪空气截留和钻井/采样过程中可能的气体损失。这项研究将产生第一个千年尺度的H2大气历史，并研究与中世纪气候异常和小冰期相关的百年尺度变化。预计H2会出现与气候相关的变异，因为主要的损失机制是土壤中的微生物吸收，这是一个对水文条件高度敏感的过程。因此，峰会的古大气H2记录将为我们理解全球H2的地球化学循环提供新的限制，并为用于评估未来H2排放的气候敏感性的全球模型提供重要的测试。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。