Collaborative Research: Studies of Chlorine, Bromine and Iodine Chemistry in the Arctic, and its Impacts

合作研究：北极氯、溴和碘化学及其影响的研究

• 批准号: 1417906
• 负责人: Christine Hrycyna
• 金额: $ 31.68万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1417906&HistoricalAwards=false
• 关键词: Collaborative; Research; Studies; Chlorine; Bromine

This project aims to improve our quantitative understanding of the impact of halogen (chlorine, bromine, and iodine) chemistry in the Arctic, so that model simulations of the impact of future changes in sea ice and snowpack conditions on atmospheric composition can be more reliably conducted. While in non-polar regions of the planet the atmosphere cleans itself through photochemistry that involves ozone, the atmosphere above sea-ice covered regions cleans itself at least in part through chemistry involving halogen atoms - chlorine, bromine and iodine. This halogen chemistry sometimes manifests itself through the very rapid (and very unusual, compared to the rest of the atmosphere) consumption of ozone and elemental mercury, to near-zero levels, in the lower atmosphere. Ozone is a critically important atmospheric constituent that is a powerful cleaning agent, but it is also toxic to plants and to the human respiratory system, and is a regulated air pollutant. Elemental mercury, when oxidized, can be converted to highly toxic forms, e.g. methyl mercury. Since this polar halogen chemistry is unique, it needs to be understood in terms of its global impact, and in the context of the rapid environmental change occurring in the Arctic.The grant would fund a collaborative team to conduct measurements of fluxes (i.e. rates of emission) of Cl2, Br2, and I2, from the saline snowpack at Barrow, Alaska. The controlling environmental variables (e.g. sunlight, presence of ozone, pH, salt concentrations, snow composition) that determine the fluxes will be studied using a snow chamber, using a variety of snow and ice samples collected at Barrow, and through direct measurements of the emission from the snowpack near Barrow. The team will then use the measured halogen fluxes and vertical mixing information to constrain a one-dimensional (vertical scale) numerical model to investigate the vertical scale impact of the surface fluxes, and to examine how this might change as the nature of the surface changes with climate change. A significant part of the discovery component of the effort will focus on molecular iodine and iodine chemistry, which has been little-explored in the Arctic to date. The broader impacts are oriented toward the goal of understanding the Arctic in order to inform better prediction of the impacts of change in the Arctic, and of the impact of Arctic change on other parts of the Earth system. A focus of this project will be the education and inspiration of the next generation of scholars, teachers, and researchers about science and the changing planet. Each of the three lead investigators will mentor both undergraduate and graduate students in the course of this project. Students who participate in the field effort at Barrow benefit from a unique experience in conducting experiments in harsh environments, managing science logistics in remote locations, and engaging in science and education partnerships with Arctic people. In partnership with this project an adventure and nature writer, Peter Lourie, will write a new book about sea ice, how scientists study it, why it is important to humans and to the planet, and how it is changing. He will also produce on-line educational material about sea ice and science in the Arctic, aimed at middle-school education. All of the participating scientists will be engaged in a range of outreach activities, including presentations at schools, involvement with "Portal to the Public" - a nationwide network of informal science education efforts - and with the active recruitment of underrepresented groups to pursue careers in science and education.

该项目旨在提高我们对北极化学（氯，溴和碘）化学影响的影响的定量理解，因此可以更可靠地进行模型对海冰和积雪条件对大气成分的影响的模型模拟。尽管在地球的非极性区域中，大气通过涉及臭氧的光化学清洁自身，而海冰覆盖区域上方的大气至少通过涉及卤素原子的化学性质（氯，溴，碘和碘）清除了自己。 在低大气中，这种卤素化学有时会通过臭氧和元素汞的消费量非常快（与其他大气的其余部分相比，与其他大气的其余部分相比，非常不寻常）表现出来。臭氧是一种至关重要的大气成分，是一种强大的清洁剂，但对植物和人类呼吸系统也有毒，并且是一种受调节的空气污染物。氧化后的元素汞可以转化为剧毒形式，例如甲基汞。由于这种极地卤素化学是独一无二的，因此需要根据其全球影响来理解它，并且在北极的快速环境变化的背景下，该赠款将资助一个协作团队，以对CL2，BR2和I2的通量测量（即排放率）进行测量。控制环境变量（例如阳光，臭氧，pH，盐浓度，雪成分）将使用雪室进行确定的通量，并使用在巴罗（Barrow）收集的各种雪和冰样品进行研究，并通过直接测量来自Barrow附近的Snowpack的发射。然后，团队将使用测量的卤素通量和垂直混合信息来限制一维（垂直尺度）数值模型来研究表面通量的垂直尺度影响，并研究这种情况可能随着表面变化而随着气候变化的变化而变化。努力的发现成分的重要部分将集中在分子碘和碘化学上，迄今为止，在北极几乎没有探索。更广泛的影响面向理解北极的目标，以便更好地预测北极变化的影响以及北极变化对地球系统其他部位的影响。该项目的重点将是下一代学者，教师和研究人员关于科学和不断变化的星球的教育和灵感。在该项目过程中，三位主要调查人员中的每一个都将指导本科生和研究生。参加Barrow的现场工作的学生可以从在恶劣环境中进行实验，在偏远地区管理科学物流以及与北极人员建立科学和教育合作伙伴关系的独特经验。与这个项目合作，冒险和自然作家彼得·劳里（Peter Lourie）将写一本关于海冰的新书，科学家如何研究它，为什么它对人类和地球很重要，以及它的变化。他还将在北极的中学教育中生产有关海冰和科学的在线教育材料。所有参与的科学家将参加一系列外展活动，包括在学校的演讲，与“公共门户”的参与 - 一个全国性的非正式科学教育工作网络，以及积极招募代表性不足的团体以从事科学和教育的职业。