Trace Elements in the Atmosphere Over the North Atlantic: Concentrations, Sources, and Fluxes

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。该AEROCE研究单元将通过测量AEROCE网络站点的大气样本来研究北大西洋上空大气中的微量元素。这些数据将用于编制北大西洋上空大气的化学气候学，即描述微量元素的平均浓度以及平均浓度的时间和区域变异性。将特别重视评估大气和海洋中的物理、化学和生物过程如何影响微量元素的浓度和通量。将调查粉尘的运输和降雨对粉尘的清除，以了解矿物粉尘的化学和海气交换如何与其他物质的地球化学循环相结合。通过考虑影响海盐生产的各种变量组合，将改进对大气海盐分布和通量的估计。将使用化学示踪剂来描绘某些元素的浓度和与采样点相邻的水域的生物生产力。

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 AEROCE research element will be concerned with studying trace elements in the atmosphere over the North Atlantic by measuring in atmospheric samples from the AEROCE Network sites. These data will be used to develop a chemical climatology for the atmosphere over the North Atlantic, i.e., a description of the mean concentrations of the trace elements and the temporal and areal variability of the means. Particular emphasis will be placed on assessing how physical, chemical, and biological processes in the atmosphere and oceans affect the concentrations and fluxes of trace elements. The transport of dust and the scavenging of dust by rain will be investigated to understand how the chemistry and air-sea exchange of mineral dust is coupled to the geochemical cycling of other substances. Improved estimates of the distribution and flux of atmospheric sea-salt will be made by considering combinations of variables that affect sea-salt production. Chemical tracers will be used to delineate the concentrations of certain elements and the biological productivity of the waters bordering the sampling sites.