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

拟议的工作是对为期四年的南极大气硫化学研究的补充，该研究包括南极站的两个夏季野外季节，一个在1998-1999年，第二个在2000-2001年。南极对流层硫化学调查(ISCAT)是一个重大项目，涉及五个机构的十名首席和高级调查人员，另外还有七名调查人员。在1998-1999年的野外季节，ISCAT的科学家们在南极站的大气边界层中发现，活性氮的水平大大超过了标准气相对流层化学模型预测的水平。由于这些氮物种不太可能是从较低纬度输送进来的，因此人们认为南极雪盖内有当地的来源。这一假设具有巨大的后果，因为它意味着雪不是大气痕量气体的简单累加器和积分器，雪和冰芯中的观测浓度不能简单地视为反映降雪时的大气条件。在2000-01年度，国际气候变化中心的观测方案将包括扩大的氮氧化物化学。硝酸和亚硝酸将在大气和雪中进行测量，减少的数据将近乎实时地用于指导ISCAT的观测计划。

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.