Collaborative Research: Antarctic Tropospheric Chemistry Investigation (ANTCI)

拟议的工作是为期四年的南极大气硫化学合作研究的一个组成部分，该研究包括2003-04年和2005-06年两个南极夏季野外季节。整个项目(南极对流层化学调查)涉及7个机构的13名首席和高级调查人员。该计划的广泛目标将是加强我们对控制南极大陆上空对流层活性氢自由基、活性氮、硫和其他痕量物种水平的过程的理解，以进一步改善对南极冰芯记录中基于硫的信号的气候解释。这些结果将提供对南极大气化学的更全面的了解，并直接导致对影响南极冰芯气候替代物种水平和分布的大气因素的进一步洞察。它是基于过去十年的其他一些硫磺研究，并从这些研究演变而来的，其中包括这组研究人员在南极内陆和沿海地点进行的早期研究。整个项目的主要科学目标将包括：1)评估控制南极大气表层中反应性自由基春季和夏季水平的详细动力和化学过程；2)评估以前获得的南极和沿海测量结果在极地高原过程的更大背景下的代表性；3)调查还原硫从海岸到高原运输所涉及的氧化过程的相对重要性，并确定化学转变的主要区域。次要目标将包括调查与大气进行广泛交换的雪/雪化学物种，以及评估微量元素的不同化学形式及其与臭氧和其他氧化剂水平的关系。大气硫化学是气候变化问题的一个重要组成部分，因为自然和人类排放的硫化物在大气中形成微小颗粒(所谓的气溶胶)，反射太阳辐射，产生大气雾霾和酸雨，并影响臭氧消耗。大气中的硫酸盐颗粒也可能作为水蒸气的凝结核，增强全球云量。硫的主要自然来源是火山排放和海洋浮游植物产生的二甲基硫。在千年时间尺度上，可以从保存下来的冰芯古记录中重建大气气溶胶的变异性和自然背景水平。然而，有必要了解氧化过程的物理和化学环境如何影响埋在冰中的氧化产物的相对浓度。

The proposed work is one component of a collaborative four-year study of the sulfur chemistry in the antarctic atmosphere, including two antarctic summer field seasons in 2003-04 and 2005-06. The overall project, (ANTCI; Antarctic Tropospheric Chemistry Investigation), involves thirteen principal and senior investigators at seven institutions. The broad based goal of this program will be to enhance our understanding of the processes that control tropospheric levels of reactive hydrogen radicals, reactive nitrogen, sulfur, and other trace species over the Antarctic continent for the further purpose of improving the climatic interpretation of sulfur-based signals in antarctic ice core records. The results will provide a far more comprehensive understanding of Antarctic atmospheric chemistry as well as lead directly to further insights about the atmospheric factors that influence the levels and distributions of climate proxy species in Antarctic ice cores. It is based on and has evolved from a number of other sulfur studies during the last decade, including earlier studies by this group of investigators in the antarctic interior and at a coastal site. This component is concerned with the measurement of non-methane hydrocarbons, halocarbons, and dimethyl sulfide in the sampled air as tracers of recent exposure to a marine environment.Major science objectives of the overall project will include: 1) evaluating the detailed dynamical and chemical processes that control spring and summertime levels of reactive radicals in the atmospheric surface layer at South Pole; 2) Assess the representativeness of the previously obtained South Pole and coastal measurements in the larger context of polar plateau processes; and 3) investigating the relative importance of the oxidative processes involved in the coast-to-plateau transport of reduced sulfur and determining the principal regions of chemical transition. Secondary objectives will include investigating snow/firn chemical species that undergo extensive exchange with the atmosphere, and assessing the different chemical forms of the trace elements and their relationships to the levels of ozone and other oxidants. Atmospheric sulfur chemistry is an important component in climate change issues because both naturally and anthropogenically emitted sulfur compounds form minute particles in the atmosphere (so-called aerosols) that reflect solar radiation, produce atmospheric haze and acid rain, and affect ozone depletion. Sulfate particles in the atmosphere may also act as condensation nuclei for water vapor and enhance global cloudiness. The primary natural sources of sulfur are volcanic emissions and DMS production by oceanic phytoplankton. On the millennial time scale the variability and natural background level of atmospheric aerosols can be reconstructed from the preserved paleorecords in ice cores. It is however necessary to understand how the physical and chemical environment of the oxidation process affects the relative concentrations of the oxidation products that become buried in the ice.