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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >ATMOSPHERIC NUCLEI AND RELATED AEROSOL FIELDS OVER THE ATLANTIC - CLEAN SUBSIDING AIR AND CONTINENTAL POLLUTION DURING ASTEX
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ATMOSPHERIC NUCLEI AND RELATED AEROSOL FIELDS OVER THE ATLANTIC - CLEAN SUBSIDING AIR AND CONTINENTAL POLLUTION DURING ASTEX

机译：大西洋清洁过程中大西洋清洁的大气和持续污染上的大气核和相关气溶胶场。

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Meteorological conditions in the Atlantic Stratocumulus Transition Experiment (ASTEX) region favored advection of clean air from the central Atlantic during the early part of the experiment that was replaced by polluted air of European origin during the latter part of the experiment. Marked differences in the aerosol size distribution, composition, and state of mixing existed in these air masses. Pronounced differences in their vertical structure also demonstrated that surface measurements often do not represent average boundary layer or column concentrations. Clean subsiding air from the free troposphere had concentrations of condensation nuclei that significantly exceeded concentrations in the boundary layer and had very low mass concentrations and volatility consistent with homogeneous nucleation aloft, supporting the hypothesis that these nuclei can provide a source for ''new'' nuclei into the marine surface layer. This finding was in contrast to polluted air characterized by high concentrations of aged aerosol but having no evidence for significant recent nuclei formation. Particles in polluted air consisted of more than 90% volatile mass (mostly sulfate) and a refractory residual remaining at 300 degrees C. The refractory mass varied with the concurrently measured light absorption coefficient, associated with combustion-derived soot. In spite of 2 orders of magnitude more volatile sulfate in polluted air, most of the particle number in polluted air remained after volatilization at 300 degrees C, in contrast to less than 10% in clean air. This finding suggests that the number of particles in polluted air may reflect the combustion process producing the primary soot aerosol more than the SO2 emissions responsible for much of the sulfate aerosol mass. The accumulation mode mass mean diameter was found to increase with total accumulation mode mass, suggesting that a size parameterization based upon the more commonly measured sulfate mass could be included in current aerosol models. [References: 29]
机译：大西洋层积云过渡试验（ASTEX）地区的气象条件有利于在试验初期对来自大西洋中部的洁净空气进行平流，在试验后期由欧洲起源的污染空气代替。这些气团中存在气溶胶尺寸分布，组成和混合状态的明显差异。垂直结构的明显差异还表明，表面测量值通常不代表平均边界层或色谱柱浓度。来自自由对流层的干净的沉降空气中的凝结核浓度大大超过边界层的浓度，并且质量浓度和挥发性都非常低，与高空均匀核一致，这支持了这些核可以提供“新”来源的假设。核进入海洋表层。这一发现与以高浓度的老化气溶胶为特征但没有证据表明近期有明显核形成的污染空气相反。被污染的空气中的颗粒由90％以上的挥发性物质（大部分为硫酸盐）和300摄氏度时的耐火残余物组成。耐火物质随同时测量的光吸收系数而变化，这与燃烧烟尘有关。尽管受污染空气中的挥发性硫酸盐含量高出两个数量级，但受污染空气中的大部分颗粒数在300摄氏度下挥发后仍保留，而在清洁空气中则不足10％。这一发现表明，受污染的空气中的颗粒数量可能反映出产生主要烟灰气溶胶的燃烧过程，而不是反映大部分硫酸盐气溶胶质量的SO2排放。发现累积模式质量平均直径随着总累积模式质量增加而增加，这表明基于更普遍测量的硫酸盐质量的尺寸参数化可被包括在当前的气溶胶模型中。 [参考：29]

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