EAGER: Improving Ice Core Observations of Large Volcanic Eruptions, and Their Effect on Global Climate Change, with a Novel Sulfur Isotope Method

EAGER：利用新型硫同位素方法改进大型火山喷发的冰芯观测及其对全球气候变化的影响

• 批准号: 1340174
• 负责人: Jess Adkins
• 金额: $ 14.78万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1340174&HistoricalAwards=false
• 关键词: EAGER; Improving; Ice; Core; Observations

The attribution of modern planetary scale warming between forcings associated with solar output, greenhouse gases, and both natural (volcanic) and anthropogenic aerosols is a challenging and important problem. To date the cooling effect of large volcanic eruptions has been determined by measuring sulfate concentrations in ice cores. However, only volcanoes that inject sulfur dioxide into the stratosphere can cause sustained global cooling as the rain out of new aerosols in the troposphere is very efficient. We need a way to distinguish volcanoes with large amounts of sulfate in the ice core record, but no stratospheric impact (like the Mount St. Helens eruption), from those that reached the stratosphere, so that they can be taken out of the volcanic forcing function in climate attribution studies.Fortunately, injection of SO2 into the stratosphere leaves a mass independent isotopic signal on the sulfur of the resulting sulfate aerosols. This research, led by a professor at the California Institute of Technology, builds on a new technique for measuring sulfur isotopes on small samples that lowers the detection limit the relevant isotopic systems by over three orders of magnitude. This new method will be used to generate a time series of sulfur isotope variability in ice cores of the top 100 volcanic events of the last 1,000 years. The researchers will identify which volcanic eruptions actually entered the stratosphere and therefore caused a global climate cooling. These are the events that must be accounted for in climate warming attribution studies. The research will focus on an ice core from South Greenland. Certain events will be cross-checked in ice cores from Antarctic to confirm the global distribution of sulfate aerosol. The results of this work could be potentially transformative in changing our understanding of the sensitivity of climate to CO2 increases. Outcomes will inform educational outreach efforts. Funding also supports an early career scientist.

与太阳能输出，温室气体以及天然（火山）和人为气溶胶相关的强迫之间的现代行星规模变暖的归因是一个具有挑战性且重要的问题。迄今为止，大型火山喷发的冷却效果已通过测量冰芯中的硫酸盐浓度来确定。但是，只有将二氧化硫注射到平流层中的火山只会导致持续的全球冷却，因为对流层中新气溶胶的降雨非常有效。我们需要一种方法来区分冰核记录中硫酸盐大量的火山，但没有平流层影响（例如圣海伦斯山（Mount St. Helens）喷发）与到达平流层的火山，以使它们可以从气候归因研究中从火山归属研究中取出。这项由加利福尼亚理工学院教授领导的这项研究以一种新技术为基础，用于测量小样本上的硫同位素，从而将检测降低相关的同位素系统降低了三个数量级以上。这种新方法将用于在过去1000年的前100个火山事件中生成时间序列的硫同位素变异性。研究人员将确定哪些火山喷发实际上进入了平流层，因此引起了全球气候冷却。这些是气候变暖归因研究中必须考虑的事件。该研究将重点放在南格陵兰的冰芯上。某些事件将在南极的冰芯中进行交叉检查，以确认硫酸盐气溶胶的全球分布。这项工作的结果可能是改变我们对气候对CO2敏感性的理解的潜在变化。成果将为教育外展工作提供信息。资金还支持早期职业科学家。