Record of Atmospheric Photochemistry in Firn at South Pole

[9811875]这项拟议的工作涉及通过测量和解释南极站雪和雪中的过氧化氢、甲醛和硝酸浓度，在过去大约200年里发展大气氧化能力的历史。主要目标是建立过去大气光化学的记录，次要目标是评估空间或时间平均的程度，以解决过去200年来这些物种浓度在统计上的显著变化。提出的方法包括全年对空气和近地表雪进行采样，夏季对雪坑和雪芯进行采样和分析，并对空气-雪化学进行建模，以解释在雪中观测到的浓度。南极站是这项工作的理想选择，因为极端寒冷使化学反应相对简单，NOAA气候模拟和诊断实验室提供了高质量的气象和化学数据背景，并且该站全年的占用使全年采样成为可能。在南方夏季，将在雪桩场周围的两个雪坑中进行密集采样（用于积累观测）。为了保持对地层、化学层位和标志物的时间控制，靠近桩田是很重要的。建模程序将扩展过氧化氢空气-雪交换的物理模型框架，该模型是由首席研究员在南极和格陵兰中部的早期工作中开发和测试的

9811875BalesThis proposed work concerns the development of a history of the oxidation capacity of the atmosphere over approximately the past two hundred years by measuring and interpreting the hydrogen peroxide, formaldehyde, and nitric acid concentrations in the snow and firn at South Pole station. The primary goal is to develop a record of past atmospheric photochemistry, with a secondary goal of evaluating the degree of spatial or temporal averaging necessary to resolve statistically significant changes in the concentration of these species over the past 200 years. The proposed approach involves year-round sampling of air and near-surface snow, summer sampling and analysis of snow pits and firn cores, and modeling the air-snow chemistry in order to interpret the observed concentrations in the firn. South Pole station is ideal for this work because the extreme cold makes the chemistry relatively simple, the NOAA Climate Modeling and Diagnostics Laboratory provides a context of high quality meteorological and chemical data, and the year-round occupation of the station makes year-round sampling possible.Intensive sampling during the austral summer will be done in two snow pits around the perimeter of the snow stake field (for accumulation observations). Proximity to the stake field is important in order to maintain time control for stratigraphic and chemical horizons and markers. The modeling program will expand on the framework of physically based models of the air-snow exchange of hydrogen peroxide developed and tested by the principal investigator during earlier work at South Pole and in central Greenland.***