• 关键词：天气形势  气象要素  气团运动  气溶胶质量浓度谱分布

• 基金项目：国家自然科学基金重点项目(No.40637035)

• 许万智
• 1. 中国气象科学研究院, 北京 100081;
  2. 中国科学院大学, 北京 100049

• 赵凤生
• 北京师范大学, 全球变化与地球系统科学研究院, 北京 100875

• 摘要：为了研究不同天气形势和气象要素对不同粒径段的大气气溶胶质量浓度谱分布的影响,2010年秋季在北京市采用空气动力学粒径仪对0.5~20 μm的大气颗粒物进行了为期2个月的连续观测.结果表明,在不同天气形势和气团运动下,质量浓度谱分布差异明显.受到西北气流影响,在质量浓度较小的清洁天气,谱分布主要集中在粗粒径段(清洁天气).当天气以静稳为主,颗粒物质量浓度值中等偏高时,粗细粒径气溶胶分布中出现谱值相近的高峰(中等浑浊天气).在受到西南气流主要影响的高质量浓度的观测日中,细粒径气溶胶在谱分布中占主要地位(高浑浊天气).在相同气团影响的天气下,昼夜间质量浓度谱分布的谱型变化趋势一致.清洁天气保持了粗粒径段的单峰分布,中等浑浊和高浑浊天气呈双峰分布.清洁天气细粒径段谱值受光化学反应影响在日间略高于夜间.中等浑浊天气中质量浓度的谱值在夜间受相对湿度和温度变化影响有显著增加.高浑浊天气下,昼夜温湿差别小,谱分布未出现明显变化.

• Abstract：In order to study the impact of different synoptic patterns and meteorological parameters on size distributions of atmospheric aerosol mass concentration, continuous measurements of particles ranging from 0.5 to 20 μm by an Aerodynamic Particle Sizer were conducted in Beijing from October to November, 2010. It was found that the aerosol size distributions varied greatly under different weather conditions. In clean weather conditions with low mass concentration influenced by the northwestern airflow, aerosols mainly accumulated in the coarse range. In moderately turbid weather, the mass concentration was moderately high and peak values were comparable in the coarse and fine ranges. In severely turbid weather impacted by the southwestern airflow, the fine particles dominated in the size distributions. With impacts by the same air mass, the mass size distribution showed similar shapes in day and night. In clean weather, the unimodal distribution was retained, while bimodal distributions were observed in both moderately and severely turbid weather. The values of fine range in the daytime were a little larger than those measured at night because of the photochemical reaction. The increasing distribution values were influenced by the variation of relative humidity and temperature for the moderate turbid weather. Under severely turbid weather conditions, with little differences in relative humidity and temperature, there was no significant change in size distribution between day and night.

• Key words：synoptic patterns  meteorological elements  air mass movement  aerosol mass concentration size distribution

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