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首页> 外文期刊>Atmospheric environment >Activity size distribution and residence time of ~7Be aerosols in the Arctic atmosphere
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Activity size distribution and residence time of ~7Be aerosols in the Arctic atmosphere

机译：北极大气中〜7Be气溶胶的活动量分布和停留时间

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摘要

The activity size distributions of the natural radionuclide tracer ~7Be in different size range fractions (<0.39 urn, 0.39-0.69 μm, 0.69-1.3 urn, 1.3-2.1 μm, 2.1-4.2 urn, 4.2-10.2 μm and >10.2 μm) were determined in the boreal atmosphere in the Arctic Research Centre of the Finnish Meteorological Institute (FMI) at Sodankyla, Finland (67°22' N, 26°38' E, 180 m asl). The activity median aerodynamic diameter (AMAD) ranged from 0.54 μm to 1.05 μm (average 0.83 μm). A residence time of about 8 days applies to aerosols of 0.83 μm diameter, representing the residence of aerosol particles in arctic environment The observed positive correlation between AMAD values and RH% can be explained by the fact that condensation during high relative humidity conditions becomes more intense, resulting in increased particle sizes of atmospheric aerosols. However, greater aerosol particle sizes means higher wet scavenging rate of aerosols and as a result lower activity concentration of ~7Be in the atmosphere, explaining the anti-correlation between the AMAD values and activity concentrations of ~7Be. But this associated with possibly higher scavenging rates of aerosols does not necessarily alone explain the anti-correlation between the AMAD and the ~7Be activities. The air mass origin associated with synoptic scale weather phenomena may contribute to that too. The Flextra model was used to assess the transport pattern and to explain the deviation in radionuclide activity concentrations and AMAD values observed in the site of investigation.
机译：天然放射性核素示踪剂〜7Be在不同尺寸范围分数（<0.39 urn，0.39-0.69μm，0.69-1.3 urn，1.3-2.1μm，2.1-4.2 urn，4.2-10.2μm和> 10.2μm）的活度分布是在芬兰Sodankyla的芬兰气象研究所（FMI）北极研究中心的北极大气中确定的（北纬67°22'，东经26°38'，180 m asl）。活动的空气动力学中位直径（AMAD）为0.54μm至1.05μm（平均0.83μm）。直径为0.83μm的气雾剂的停留时间约为8天，代表了气溶胶颗粒在北极环境中的停留时间。在较高的相对湿度条件下冷凝会变得更强烈，这说明了AMAD值与RH％之间的正相关关系。 ，导致大气气溶胶的粒径增加。但是，较大的气溶胶粒径意味着较高的气溶胶湿清除率，因此大气中的〜7Be活性浓度较低，这解释了AMAD值与〜7Be活性浓度之间的反相关性。但这可能与更高的气溶胶清除率有关，并不一定单独解释了AMAD和〜7Be活性之间的反相关性。与天气尺度天气现象有关的空气质量起因也可能是这一原因。 Flextra模型用于评估运输模式并解释在研究现场观察到的放射性核素活度浓度和AMAD值的偏差。

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