Collaborative Research: NSFGEO-NERC: Recent changes in Arctic biogenic sulfur aerosol from a central Greenland ice core

合作研究：NSFGEO-NERC：格陵兰中部冰芯北极生物硫气溶胶的最新变化

• 批准号: 2230350
• 负责人: Becky Alexander
• 金额: $ 62.74万
• 依托单位: University of Washington
• 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: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230350&HistoricalAwards=false
• 关键词: Collaborative; Research; NSFGEO; NERC; Recent

This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries.Sulfur aerosols cool the climate. The amount of sulfur aerosol in the Arctic has varied dramatically in the recent past due mostly to sulfur aerosol from coal combustion. Sulfur emissions from coal combustion increased at the onset of the Industrial Revolution and have been decreasing since the 1970s because of the implementation of policies in the US and Europe to reduce air pollution. As human emissions decline, natural sulfur sources, such as from microscopic plants in the ocean, are becoming more important. The ocean biological source of sulfur aerosol may also be changing with a changing Arctic climate, particularly due to the melting of sea ice. This project will measure the two main chemical sources of sulfur aerosol in the Arctic, methane sulfonic acid (MSA) that is only from ocean biology, and sulfate, that originates from ocean biology, volcanoes, and combustion of coal and oil. The project will measure the sulfur isotopic composition of the chemicals in order to distinguish the ocean biological source from the other two sources and determine how large each source is and how fast each is changing. These measurements will provide a way to determine if and how ocean microscopic plants and their sulfur emissions are responding to Arctic climate change. This project will support the training of two graduate students and several undergraduate students. The students and PIs will participate in local outreach events in Seattle, WA and in Brookings, SD. We will work with the School of Ice to produce a new Virtual Field Lab geared towards students from middle school through early college. Ice-core observations of methane sulfonic acid (MSA) are used as a proxy for past oceanic biogenic productivity because MSA originates solely from the oxidation of dimethyl sulfide (DMS) emitted by ocean phytoplankton. Previous research using Greenland ice cores showed a detectable MSA decline since the 1800s, implying decreasing oceanic biogenic productivity. The use of MSA as a proxy for biogenic productivity relies on the assumption that the branching ratio of production of MSA versus sulfur dioxide (SO2) from DMS oxidation remains constant over time. However, recent examination of MSA and isotopic composition of sulfate in Greenland ice cores over the last 800 years shows that the ratio of MSA-to- biogenic sulfate (MSA/bioSO4) has not remained constant. This project hypothesizes that recent trends in MSA are driven by changes in oxidant abundances (e.g., NOx) that lead to a reduced yield of MSA and increased yield of SO2 during oxidation of DMS. The project will test this hypothesis by measuring ion and MSA concentrations and sulfur isotopes of sulfate in Greenland snow accumulated over the last 30 years. The last 30 years will cover the time when anthropogenic NOx emissions from North America and Europe began to decline (after the mid-1990s). In collaboration with University of St. Andrews in United Kingdom, the project will also measure sulfate isotopes at sub-seasonal resolution over the last 30 years from the proposed shallow ice cores in addition to select, discrete samples from archived ice in the preindustrial. Measuring biogenic sulfate at seasonal resolution since the preindustrial will allow for investigation of changes in the seasonality of biogenic sulfur aerosol in the Arctic resulting from changes in Arctic climate. To assist data interpretation, the global chemical transport model GEOS-Chem will be used to quantify the role of different oxidants on DMS oxidation as these oxidants have changed due to anthropogenic emissions. This project has broad implications for the ice-core, climate, and atmospheric chemistry communities because the results will improve our understanding of the impacts of Arctic climate change and anthropogenic emissions on biogenic sulfur aerosols, and thus our understanding of a potentially important climate feedback at high latitudes and future climate projections. This project will support the training of two graduate students and several undergraduate students at the UW and SDSU in ice-core processing, chemical and isotopic analysis, global modeling, and international collaboration. The students and PIs will participate in local outreach events in Seattle, WA and in Brookings, SD. The team will work with the School of Ice to produce a new Virtual Field Lab geared towards students from middle school through early college. The first-time partnership with University of St. Andrews will enhance scientific outcomes.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.

这是一个由国家科学基金会地球科学理事会（NSF/GEO）和联合王国国家环境研究理事会（NERC）通过NSF/GEO-NERC牵头机构协议联合资助的项目。该协议允许美国/英国提交一份联合提案，并由研究者拥有最大预算比例的机构进行同行评审。在成功地共同确定一项奖励建议后，每个机构将资助各自国家机构的科学家的预算比例。硫气溶胶冷却气候。最近，北极地区的硫气溶胶数量变化很大，主要是由于燃煤产生的硫气溶胶。煤炭燃烧的硫排放在工业革命开始时增加，自20世纪70年代以来一直在减少，因为美国和欧洲实施了减少空气污染的政策。随着人类排放量的减少，天然硫源，如海洋中的微生物，变得越来越重要。硫气溶胶的海洋生物来源也可能随着北极气候的变化而变化，特别是由于海冰的融化。该项目将测量北极地区硫气溶胶的两个主要化学来源，即仅来自海洋生物的甲烷磺酸（MSA）和来自海洋生物、火山以及煤和石油燃烧的硫酸盐。该项目将测量化学品的硫同位素组成，以区分海洋生物来源和其他两个来源，并确定每个来源的规模和变化速度。这些测量将提供一种方法来确定海洋微生物及其硫排放是否以及如何对北极气候变化做出反应。该项目将支持两名研究生和几名本科生的培训。学生和PI将参加在华盛顿州西雅图和南达科他州布鲁金斯的当地外展活动。我们将与冰的学校，以产生一个新的虚拟现场实验室面向学生从中学到大学早期。冰芯观测甲烷磺酸（MSA）被用作过去海洋生物生产力的代理，因为MSA完全来自海洋浮游植物排放的二甲基硫（DMS）的氧化。先前使用格陵兰冰芯的研究显示，自19世纪以来，海洋生物生产力下降，这意味着海洋生物生产力下降。使用MSA作为生物生产力的代表依赖于这样的假设，即MSA与来自DMS氧化的二氧化硫（SO2）的生产的分支比随时间保持恒定。然而，最近对格陵兰冰芯中硫酸盐的MSA和同位素组成的研究表明，在过去的800年中，MSA与生物硫酸盐的比例（MSA/bioSO 4）并没有保持恒定。该项目假设MSA的最新趋势是由氧化剂丰度的变化驱动的（例如，NOx），这导致在DMS的氧化期间MSA的产率降低和SO2的产率增加。该项目将通过测量过去30年来格陵兰岛积雪中硫酸盐的离子和MSA浓度以及硫同位素来检验这一假设。过去30年将涵盖北美和欧洲的人为氮氧化物排放量开始下降的时间（20世纪90年代中期之后）。该项目还将与联合王国圣安德鲁斯大学合作，除了从工业化前的存档冰中选取离散样本外，还将从拟议的浅冰芯中以亚季节分辨率测量过去30年的硫酸盐同位素。自工业化前以来，以季节分辨率测量生物源硫酸盐将允许调查北极气候变化导致的北极生物源硫气溶胶的季节性变化。为了协助数据解释，将使用全球化学迁移模型GEOS-Chem来量化不同氧化剂对二甲基硫氧化的作用，因为这些氧化剂由于人为排放而发生了变化。该项目对冰芯，气候和大气化学界具有广泛的影响，因为其结果将提高我们对北极气候变化和人为排放对生物硫气溶胶影响的理解，从而提高我们对高纬度潜在重要气候反馈和未来气候预测的理解。该项目将支持两名研究生和几名本科生在华盛顿大学和SDSU在冰芯处理，化学和同位素分析，全球建模和国际合作的培训。学生和PI将参加在华盛顿州西雅图和南达科他州布鲁金斯的当地外展活动。该团队将与冰上学校合作，为从中学到大学早期的学生建立一个新的虚拟现场实验室。与圣安德鲁斯大学的首次合作将提高科学成果。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。