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

在过去的10-15年里，大气化学已经从一个主要致力于研究城市污染和空气质量等局部问题的年轻研究学科发展成为一门涉及各种化学物质在半球到全球范围内循环的成熟科学。在很大程度上，这种变化是由于人们日益认识到，人类活动可以对自然对流层造成化学干扰，其规模远远超出当地的关注范围。众所周知的例子包括某些氮化合物、铅和其他重金属、人工放射性核素、一些合成有机物质、某些形成酸的物种、二氧化碳和甲烷的区域到全球浓度的变化。大气中的这些化学变化通常可以扩展到远离原始来源地区的地球土壤、海洋和生物群。它们可能导致地球气候的变化，重要的营养循环的变化，并对地球上的公共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。欧空局项目的最终目标将是发展在北大西洋上空海洋对流层观测到的大陆衍生物种的预测能力。在AEROCE中，地点的选择和测量方案是由建模人员和现场实验人员共同制定的。AEROCE项目的这一要素旨在提供关于222Rn和210Pb浓度时空分布的大量数据和信息，这些数据和信息将用于“校准”模拟痕量大气物种的运输和去除的模型。222Rn的化学惰性使其成为验证模型传输部分的近乎理想的物质。对222Rn的子核素210Pb的研究可以提供有关海洋大气中气溶胶去除过程的有用信息，从而为其他微量物质的这些过程的建模提供指导。建议使用经过验证的222Rn和210Pb采样和分析方法，作为AEROCE的一个组成部分，提供北大西洋岛屿站点上这两种天然放射性示踪剂浓度的地面空气测量。采样方案将在222Rn的每个站点连续提供4小时的采样，从启动时间到项目结束。在不同气团之间选定的形成良好的锋面通过时，将在同一地点采集过滤样品进行210Pb分析。从预测通过时间前12小时开始，到通过时间后12小时结束，采集一小时样本。每月将在每个地点抽取大约一组24个样本。将使用数据分析方法对所得数据进行解释，以将浓度与气团特征联系起来，并生成一组统计特征（4小时、日、季节和年平均值以及相关的标准差）。

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).