South Pole Atmospheric Nitrate Isotopic Analysis (SPANIA)

南极大气硝酸盐同位素分析 (SPANIA)

• 批准号: 0125761
• 负责人: Mark Thiemens
• 金额: $ 33.83万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0125761&HistoricalAwards=false
• 关键词: South; Pole; Atmospheric; Nitrate; Isotopic

This award supports a detailed laboratory analysis of the mass-independent isotopic composition of processes associated with atmospheric nitrate trapped in the snow pack at the South Pole. The project will specifically test if the oxygen isotopes 16O, 17O, 18O of nitrate can be used to probe the denitrification of the Antarctic stratosphere. Despite decades of research, there are several important issues in Antarctic atmospheric science, which are presently inadequately resolved. This includes quantification over time of the sources of nitrate aerosols. Today, little is known about the past denitrification of the stratosphere in high latitude regions. This lack of knowledge significantly limits our ability to understand the chemical state of ancient atmospheres and therefore evaluate present and past-coupled climate/atmosphere models. The role of nitrogen in environmental degradation is well known. This issue will also be addressed in this proposal. Atmospheric aerosols have now been shown to possess a mass-independent oxygen isotopic content. The proposed research will investigate the stable oxygen isotope ratios of nitrate in Antarctica both collected in real time and from the snow. Two periods of time will be covered. Full year nitrate aerosol collections, with week resolution time horizons, will be performed at the South Pole. Weekly aerosol collections will help us to identify any seasonal trend of the oxygen-17 excess anomaly, and eventually link this anomaly to the denitrification of the Antarctic stratosphere. This data set will also be used to test our assumption that the oxygen isotopic anomaly of nitrate is mainly formed in the stratosphere and is well preserved in the snow pack. If true, we will for the first time resolve an atmospheric signal extracted from a nitrate profile. The snow pit will allow us to see any trend in the data on a multiple decade timescale.

该奖项支持对与南极积雪中捕获的大气硝酸盐相关过程的与质量无关的同位素组成进行详细的实验室分析。该项目将专门测试硝酸盐的氧同位素16O、17O、18O是否可以用于探测南极平流层的反硝化作用。 尽管经过了数十年的研究，南极大气科学仍有几个重要问题目前尚未得到充分解决。这包括随着时间的推移对硝酸盐气溶胶来源进行量化。如今，人们对高纬度地区平流层过去的反硝化作用知之甚少。这种知识的缺乏极大地限制了我们了解古代大气的化学状态并因此评估当前和过去耦合的气候/大气模型的能力。氮在环境退化中的作用是众所周知的。这个问题也将在本提案中得到解决。 现在已证明大气气溶胶具有与质量无关的氧同位素含量。拟议的研究将调查实时收集和从雪中收集的南极洲硝酸盐的稳定氧同位素比率。将涵盖两个时间段。全年硝酸盐气溶胶收集（分辨率时间范围为周）将在南极进行。每周气溶胶收集将帮助我们识别氧 17 过量异常的任何季节性趋势，并最终将这种异常与南极平流层的反硝化联系起来。该数据集还将用于检验我们的假设，即硝酸盐的氧同位素异常主要形成于平流层，并在积雪中保存完好。如果属实，我们将首次解析从硝酸盐剖面中提取的大气信号。雪坑将使我们能够看到数十年时间尺度上数据的任何趋势。