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岛萨米特冰芯中的分子氢 (H2)，以重建过去千年大气中氢气的变化。这将是工业时代开始之前大气中氢气的首次记录。结果将揭示古大气氢气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前工业时代以来人类活动如何影响大气中的氢气提供基线。这项研究的结果将为未来氢经济将如何影响大气成分和气候的全球评估提供信息。该项目将为博士后学者和本科生提供培训。该研究包括在 Summit 钻探一个新冰芯，从现场样本中提取空气，随后分析 H2、Ne 和 CH4。古大气中的 H2 水平将从观测到的 H2/Ne 比率推断出来，以解释空气截留过程中的孔隙封闭分馏以及钻井/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氢气历史，并研究与中世纪气候异常和小冰河时代相关的百年尺度变化。预计氢气会出现与气候相关的变化，因为主要的损失机制是土壤中微生物的吸收，这一过程对水文条件高度敏感。因此，Summit 古大气氢气记录将为我们了解氢气的全球生物地球化学循环提供新的约束，也是对用于评估未来氢气排放的气候敏感性的全球模型的重要测试。该奖项反映了 NSF 的法定使命，并被视为值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。