Air-Snow Exchange of Nitric and Nitrous Acids at South Pole

这项拟议的工作是对南极大气中硫化学为期四年的研究的补充，其中包括南极站的两个夏季实地季节，一个在1998-99年，第二个在2000-01年。南极对流层硫化学研究（ISCAT）是一个重大项目，涉及5个机构的10名主要和高级研究人员以及另外7名贡献研究人员。在1998-99年的野外季节，ISCAT科学家发现南极站大气边界层中的活性氮水平大大超过了标准气相对流层化学模型预测的水平。由于这些氮极不可能是从低纬度地区运来的，因此人们认为南极积雪中有当地的来源。这一假设具有巨大的影响，因为它意味着雪并不是大气中微量气体的简单累积者和积分者，而且观测到的雪和冰芯中的浓度不能简单地看作是降雪时大气状况的反映。在2000-01季节，ISCAT的观测方案将包括扩展的氮氧化物化学。硝酸和亚硝酸盐将在大气和雪中进行测量，减少的数据可以近实时地指导ISCAT观测计划。

The proposed work is an addition to a four-year study of the sulfur chemistry in the antarctic atmosphere, including two summer field seasons at South Pole station, one in 1998-99 and the second to occur in 2000-01. Investigations of Sulfur Chemistry in the Antarctic Troposphere (ISCAT) is a major project, involving ten principal and senior investigators at five institutions with seven additional contributing investigators. During the 1998-99 field season ISCAT scientists found levels of reactive nitrogen in the atmospheric boundary layer at South Pole station that greatly exceeded levels predicted from standard gas phase tropospheric chemistry models. Since it is highly unlikely that these nitrogen species could have been transported in from lower latitudes, it was supposed that there is a local source within the antarctic snow cover. This supposition has enormous consequences because it means that the snow does not act as a simple accumulator and integrator of atmospheric trace gases, and that observed concentrations in snow and ice cores cannot be simply taken as reflecting atmospheric conditions at the time the snow was falling. In the 2000-01 season the observational protocol of ISCAT will include an expanded nitrogen oxide chemistry. Nitric and nitrous acid will be measured both in the atmosphere and in the snow, with the reduced data available in near-real time to guide the ISCAT observational program.