NSFGEO-NERC: Impacts of sea ice melt and anthropogenic emmisions on biogenic sulfur aerosol as measured in a central Greenland ice core

NSFGEO-NERC：在格陵兰中部冰芯中测量的海冰融化和人为排放对生物硫气溶胶的影响

• 批准号: NE/Y001710/1
• 负责人: Andrea Burke
• 金额: $ 29.68万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY001710%2F1
• 关键词: NSFGEO; NERC; Impacts; sea; ice

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. 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 Greenland ice-core observations of MSA and biogenic sulfate over the last 800 years show that the ratio of MSA-to-biogenic sulfate (MSA/bioSO4) has not remained constant.We hypothesize 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.We propose to drill shallow ice cores at Summit, Greenland covering the last 30 years of snow accumulation and measure ion and MSA concentrations and sulfur isotopes of sulfate. The last 30 years will cover the time when anthropogenic NOx emissions from North America and Europe began to decline (after the mid-1990s). This will yield an additional 16 years of data compared to our current record extending from 1200 C.E. through 2006.We hypothesize that the MSA/bioSO4 ratio continues to increase from the mid-1990s to the present day due to decreases in NOx emissions in North America and Europe.To assist data interpretation, we will utilize a global chemical transport model GEOS-Chem in order to quantify the role of different oxidants on DMS oxidation as these oxidants have changed due to anthropogenic emissions. We will measure sulfate isotopes at sub-seasonal resolution over the last 30 years of snow accumulation from the proposed shallow ice cores in addition to select, discrete samples from archived ice in the preindustrial.We hypothesize that DMS emissions peak earlier in in the year today than in the preindustrial due to the earlier sea-ice melt resulting from Arctic warming.Measuring biogenic sulfate at seasonal resolution since the preindustrial will allow us to investigate changes in the seasonality of biogenic sulfur aerosol in the Arctic resulting from changes in Arctic climate. This is a collaborative project between PIs in the US and the UK, and the UK part of the project will be supported by NERC.

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。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，最近格陵兰冰芯观测MSA和生物硫酸盐在过去800年显示，MSA-生物硫酸盐（MSA/bioSO 4）的比例并没有保持不变。我们假设MSA的最近趋势是由氧化剂丰度的变化驱动的（例如，氮氧化物），导致产量减少的MSA和增加产量的SO2氧化过程中的DMS。我们建议钻浅冰芯，格陵兰岛的首脑会议，覆盖了过去30年的积雪和测量离子和MSA浓度和硫同位素的硫酸盐。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）。这将产生一个额外的16年的数据相比，我们目前的记录从1200 C.E.通过2006年。我们假设，MSA/bioSO 4的比例继续增加，从20世纪90年代中期到现在的一天，由于在北美和欧洲的氮氧化物排放量的减少。为了帮助数据的解释，我们将利用全球化学传输模型GEOS-Chem，以量化不同的氧化剂对DMS氧化的作用，因为这些氧化剂已经改变，由于人为排放。我们将在过去30年的雪积累中以亚季节分辨率测量硫酸盐同位素，除了选择，我们假设DMS排放量在今天比在前工业化时期更早达到峰值，这是由于更早的海洋-北极变暖导致的冰融化。自工业化前以来，以季节分辨率测量生物源硫酸盐将使我们能够调查北极生物源硫气溶胶的季节性变化这是北极气候变化的结果。这是美国和英国PI之间的合作项目，该项目的英国部分将由NERC提供支持。