A Study of Radon-222 and Lead-210 Distribution and Transport in the North Atlantic

在过去的10-15年里，大气化学已经从一门主要致力于城市污染和空气质量局部问题的年轻研究学科发展成为一门关注从半球到全球范围内各种化学物种的循环的成熟科学。在很大程度上，这一变化是因为人们日益认识到，人类活动可能对自然对流层造成化学干扰，其规模远远超出了当地的关切。众所周知的例子包括某些氮化合物、铅和其他重金属、人造放射性核素、一些合成有机物质、某些产酸物种、二氧化碳和甲烷的区域对全球浓度的变化。大气中的这些化学变化通常会延伸到地球的土壤、海洋和远离原始来源地区的生物群。它们可能导致地球气候的变化，改变重要的营养循环，并对地球上的公众健康和生活质量产生重大影响。大气/海洋化学实验(AEROCE)将是一个以北大西洋区域为中心的协调的多机构大气和海洋化学研究项目。AEROCE项目的最终目标将是发展对北大西洋上空海洋对流层观察到的大陆衍生物种的预测能力。AEROCE的场地选择和测量方案是由模型师和现场实验者共同开发的。AEROCE项目的这一部分旨在提供关于222Rn和210Pb浓度的时间和空间分布的大量数据和信息，这些数据和信息将可用于“校准”模拟痕量大气物种的传输和清除的模型。222Rn的化学惰性使其成为验证模型运输部分的近乎理想的物质。对222Rn、210Pb子核素的研究可以为海洋大气中发生的气溶胶去除过程提供有用的信息，从而为其他痕量物质的这些过程的模拟提供指导。提议使用经过验证的222Rn和210Pb采样和分析方法，作为AEROCE的一个组成部分，对北大西洋岛屿上这两种天然放射性示踪剂的浓度进行地面空气测量。该抽样方案将从启动时间到项目结束，在每个222Rn站点连续提供4小时样本。过滤器样本将在相同的地点进行210Pb分析，期间将选择结构良好的锋面在对比气团之间通过。从预报通过时间的12小时前开始，到通过后12小时结束，将采集一小时的样本。每个地点每月会抽取约一组样本，每组约24个。将使用数据分析方法解释产生的数据，以将浓度与空气质量特征相关联，并产生一系列统计特征(4小时、日平均、季节和年平均以及相关的标准偏差)。

Over the past 10-15 years atmospheric chemistry has evolved from a young research discipline devoted primarily to local problems of urban pollution and air quality to a mature science concerned with the hemispheric to global scale cycling of a wide variety of chemical species. To a large extent this change has resulted from an increasing realization that human activities can cause chemical disturbances to the natural troposphere on scales far beyond local concerns. Well-known examples include changes in the regional-to-global concentrations of certain nitrogen compounds, lead and other heavy metals, artificial radionuclides, a number of synthetic organic substances, certain acid-forming species, carbon dioxide and methane. These chemical changes in the atmosphere can often extend to the earth's soils, oceans, and biota far from the original source region. They can result in alterations in the earth's climate, changes in vital nutrient cycles, and impact significantly on the public health and quality of life on earth. The Atmosphere/Ocean Chemistry Experiment (AEROCE) will be a coordinated multi-institutional atmospheric and marine chemistry research project centered in the North Atlantic region. The ultimate goal of the AEROCE project will be the development of a predictive capability for the continentally derived species observed in the marine troposphere over the North Atlantic. The selection of sites and the measurement protocol in AEROCE has been developed jointly by modelers and field experimentalists. This element of the AEROCE project is designed to provide a body of data and information on the temporal and spatial distributions of concentrations of 222Rn and 210Pb which will be usable for the "calibration" of models that simulate the transport and removal of trace atmospheric species. The chemical inertness of 222Rn makes it a nearly ideal substance for validating the transport portion of the models. Study of the daughter nuclide of 222Rn, 210Pb, can give useful information on the aerosol removal processes occurring in the marine atmosphere and thereby provide guidance in the modeling of these processes for other trace substances. It is proposed to use proven methods of sampling and analysis of 222Rn and 210Pb to provide, as a component of AEROCE, surface level air measurements of the concentrations of these two naturally occurring radioactive tracers on island sites in the North Atlantic Ocean. The sampling scheme will provide 4-hour samples at each site of 222Rn continuously from start-up time to the end of the project. Filter samples will be taken for 210Pb analyses at the same sites during passages of selected well-formed fronts between contrasting air masses. One-hour samples will be taken starting 12 hours before the forecast passage time and ending 12 hours after passage. About one set of 24 samples will be taken each month at each location. The resulting data will be interpreted using data-analytical methods to correlate the concentrations with the air mass characteristics and to generate a body of statistical characteristics (4-hour, diurnal, seasonal, and annual averages and associated standard deviations).