Collaborative Research: Antarctic Tropospheric Chemistry Investigation (ANTCI)

拟议的工作是一个为期四年的合作研究在南极大气中的硫化学的一个组成部分，包括两个南极夏季在2003-04和2005-06赛季。 整个项目（南极对流层化学调查）涉及七个机构的十三名主要和高级调查员。该计划的广泛目标将是提高我们对控制南极大陆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，以进一步改善南极冰芯记录中硫基信号的气候解释。 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中气候代理物种水平和分布的大气因素的进一步了解。 它是基于并从过去十年中的一些其他硫的研究，包括早期的研究，这组调查人员在南极内陆和沿海地区。 该部分涉及对活性氢自由基、硫酸及其硫前体以及紫外线辐射通量的观测。整个项目的主要科学目标将包括：（1）评价控制南极大气表层春季和夏季活性自由基水平的详细动力学和化学过程;（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大背景下的代表性;（3）研究还原态硫从海岸向高原迁移过程中氧化过程的相对重要性，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/积雪化学物质，并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，因为自然和人为排放的硫化合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以作为水汽的凝结核，增加全球云量。 硫的主要自然来源是火山排放物和海洋浮游植物产生的二甲硫醚。 利用冰芯中保存的古记录，可以重建千年时间尺度上大气气溶胶的变率和自然背景水平。 然而，有必要了解氧化过程的物理和化学环境如何影响埋藏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 making observations of reactive hydrogen radicals, sulfuric acid and its sulfur precursors, and the flux of ultraviolet radiation. 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.