Weakness of the weekend effect in aerosol number concentrations

详细信息	查看全文 | 推荐本文 |

• 作者：Ari Asmi ; ^{ari.asmi@helsinki.fi}
• 关键词：Cloud condensation nuclei ; Weekend effect ; Aerosol number concentration ; Wavelet analysis ; Time-scale analysis
• 刊名：Atmospheric Environment
• 出版年：2012
• 期刊代码：11_13522310
• 类别：env
• 出版时间：May, 2012
• 卷：51
• 期：Complete
• 页码：100-107
• 文件大小：755 K

摘要

Weekday related anthropogenic aerosol emissions have been suggested to affect regional climate via indirect aerosol effects. I studied the variability of potential cloud condensation nuclei using measurements of number size distributions of Cloud Condensation Nuclei (CCN)-sized aerosol particles and CCNs measured at several European regional background stations, located at a wide variety of environments. With notably rare exceptions, there were no statistically significant difference between concentrations on different weekdays. I further analysed the concentration time-series of four long-period datasets in Germany and Finland with wavelet analysis. Outside of urban areas, very little weekday-connected variability was found. The lack of 7-day variability outside of cities is in contrast of earlier studies in this field, which used mostly particle mass as the representative measure of aerosol concentration. A聽time-scale and variability analysis showed that PM₁₀ and PM_2.5 are more sensitive for the weekly variation than CCN-sized particles. Using mass-based variations as a proxy for short-term variations of CCN particle numbers can thus overestimate the weekend effect for these particles. The results of this study do not support aerosol indirect effects from 50 to 500聽nm diameter particles as a major contributor on potential weekday connected variations in European meteorology.