Deciphering the Antarctic MSA-sea Ice Link with a Combined Regional Forecast and Atmospheric Chemistry Model

利用区域预报和大气化学组合模型破译南极 MSA-海冰联系

• 批准号: 0739127
• 负责人: Cecilia Bitz
• 金额: $ 37.54万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0739127&HistoricalAwards=false
• 关键词: Deciphering; Antarctic; MSA; sea; Ice

AbstractPI: Cecilia M. BitzProposal Number: 0739127 Title: Deciphering the Antarctic MSA-sea ice link with a combined regional forecast and atmospheric chemistry modelIntellectual merit: Sea ice plays multiple important roles in the climate system including reflecting solar radiation, influencing ocean heat uptake, contributing to dense water formation and protection of ice shelves by damping ocean wave action. Reliable records of Antarctic sea ice extent are only available since 1979. In order to further quantitative understanding of the role of Antarctic sea ice in climate, it would be highly desirable to have a longer term record of Antarctic sea ice conditions. Marine phytoplankton produce dimethylsulfide (DMS) which is emitted to the atmosphere where it can be oxidized to methanesulfonic acid (MSA) and sulfur dioxide and eventually deposited in continental ice. Sulfur dioxide can be converted to non seasalt (nss) sulfate or dry deposited to the ice. It has been suggested that MSA and nss sulfate deposited in ice cores can serve as a proxy for sea ice conditions although available evidence shows the relationship can be complicated by several factors including variability in emissions, variability in transport, reactions in transport and variability in deposition. Moreover there remain uncertainties with respect to the relationship between sea-ice and emissions. Whereas it might be presumed that sea ice would limit the growth of phytoplankton and prevent the escape of DMS, some of the highest concentrations of DMS in the marine environment have been measured in melting Antarctic sea ice. The Antarctic Integrated System Science Program ahs funded this project to use an interdisciplinary modeling approach to assess these factors and uncertainties to help determine whether and where sea ice conditions might be reliably extracted from MSA and nss sulfate levels in Antarctic ice cores ice cores. Specifically the MSA-climate relationship will be examined over the period of 1979-2002 using a relatively high resolution regional chemistry model based on the Community Multi-scale Air Quality (CMAQ) modeling system. Meteorological conditions will be input from hind-casts of Polar MM5 (Ohio State polar specific modifications of the fifth-generation Penn State University/National Center for Atmospheric Research Mesoscale Model)/ Large scale chemical boundary conditions will be input from a global chemical transport model, GEOS-Chem (Goddard Earth Observing System-Chemistry). Under collaborative arrangements with high latitude phytoplankton and sea ice algae experts, empirical DMS emissions within the model domain from sea ice will be developed and compared with modeled DMS emissions from an ocean general circulation model that includes sea ice, phytoplankton and sea ice algae. The overall model output will be compared with measurements from atmospheric monitoring sites and depositional records in snow and ice including widely distributed annually resolved records that are being undertaken as part of the International Polar Year (IPY) International Traverses of Antarctica for Science and Education (ITASE). Broader impacts: By investigating the links between MSA and nss sulfate levels in ice cores and sea ice conditions, this project could provide a basis to help advance the understanding of the role of Antarctic sea ice in the global climate system. The project directly combines expertise in global climate modeling, sea ice, and atmospheric chemistry and through collaboration, in marine phytoplankton ecology. A graduate student who is credited with conceiving of this proposal will be supported to conduct his PhD thesis on this interdisciplinary topic. As one element of the marine phytoplankton ecology collaboration, this student is intending to undertake an NSF East Asia Pacific Summer Institute internship in Australia with experts in sea ice algae dimethylsulfonic acid propionate (DMSP, a precursor to DMS) production. Outreach related to the research will be conducted at the annual Polar Science Weekend at the Pacific Science Center in Seattle. Two of the investigators are members of an underrepresented group (female) in climate related science and are early in their academic careers.

AbstractPI: Cecilia M. BitzProposal Number: 0739127 Title: Deciphering the Antarctic MSA-sea ice link with a combined regional forecast and atmospheric chemistry modelIntellectual merit: Sea ice plays multiple important roles in the climate system including reflecting solar radiation, influencing ocean heat uptake, contributing to dense water formation and protection of ice shelves by damping ocean wave action. 南极海冰范围的可靠记录只有自1979年以来才能获得。为了进一步定量了解南极海冰在气候中的作用，高度希望拥有南极海冰条件的长期记录。海洋浮游植物产生二甲基硫化物（DMS），该二甲基硫化物（DMS）发射到大气中，可以将其氧化为甲磺酸（MSA）和二氧化硫，并最终沉积在大陆冰中。 二氧化硫可以转化为硫酸盐（NSS）或沉积在冰上的干燥。 已经提出，沉积在冰芯中的MSA和NSS硫酸盐可以作为海冰条件的代理，尽管可用的证据表明，这种关系可能会因发射的可变性，运输变异性，运输反应，运输反应和沉积变异性而变得复杂。此外，关于海冰与排放之间的关系仍然不确定。鉴于可以假定海冰会限制浮游植物的生长并防止DMS的逃脱，但在融化南极海冰中，已经测量了海洋环境中某些DM的最高浓度。 南极综合系统科学计划AHS资助了该项目，使用跨学科建模方法评估这些因素和不确定性，以帮助确定在南极冰核中是否可以可靠地从MSA和NSS硫酸盐水平可靠地提取海冰条件。特别是MSA气候关系将在1979 - 2002年期间使用基于社区多规模空气质量（CMAQ）建模系统的相对较高的分辨率区域化学模型进行检查。气象条件将来自极地MM5的后部量（俄亥俄州州极地极地特定的修改宾夕法尼亚州立大学/国家大气研究中心中心中心中心）/大规模化学边界条件将从全球化学传输模型，Geos-Geos-Chem（Goddard Earth Cometing System-Chemistry System-Chemistry-Chemistion）中输入。在与高纬度浮游植物和海冰藻类专家的合作安排下，将开发出海冰模型域内的经验DMS排放，并将其与海洋一般循环模型的建模DMS排放量进行比较，包括海冰，浮游植物，浮游植物和海冰藻类。 总体模型输出将与大气监测地点的测量值和冰冰中的沉积记录进行比较，包括每年分布广泛的每年分布的记录，这些记录是作为国际极性年（IPY）国际科学和教育（ITASE）国际国际遍历的一部分进行的。 更广泛的影响：通过研究MSA与NSS硫酸盐水平与冰芯和海冰条件的联系，该项目可以提供一个基础，以帮助促进对南极海冰在全球气候系统中的作用的理解。该项目直接结合了全球气候建模，海冰和大气化学的专业知识，并通过合作，海洋浮游植物生态学。 一名因构思这一提议而被认为的研究生将受到支持，以对这个跨学科主题进行博士学位论文。作为海洋浮游生物生态学合作的一个要素，该学生打算在澳大利亚在澳大利亚进行NSF东亚夏季研究所实习，并与海冰藻类二甲基磺酸的专家丙酸（DMSP，DMSP，DMS的前体）生产。与研究相关的外展活动将在西雅图太平洋科学中心的年度极地科学周末进行。两名研究人员是与气候相关科学的人数不足的群体（女性）的成员，并且是其学术职业的早期。