气团来源对瓦里关地区颗粒物数谱分布的影响

The Influence of Air Mass Sources on the Particle Number Concentration and the Size Distribution at Mt. Waliguan

通过对2005年8月到2007年5月在瓦里关全球本底站观测的气溶胶数谱分布资料和同期后向轨迹资料分析,发现气团来源对瓦里关地区颗粒物的数浓度及其谱分布有显著影响.气团起源于瓦里关东北部地区或者途径东北部地区,传输路径较短,传输速度相对较慢,大气中出现较高数浓度的爱根核模态颗粒物;气团来源于瓦里关西部或者西北地区时,传输路径较长,传输速度较快,大气中一般出现较高浓度的核模态颗粒物.

Particle number size distribution of 12500 nm was measured at Mt.Waliguan,China Global Atmosphere Watch Baseline Observatory from Aug.2005 to May 2007.72-hr back trajectories at 100 m arrival height above ground level for the same period were calculated at 6：00,12：00,21：00（Beijing Time） for each day using the HYbrid Single Particle Lagrangian Integrated Trajectory（HYSPLIT-4） model developed by NOAA/ARL.It is found that the air mass sources have significant impact on the particle number concentration and size distribution at Mt.Waliguan.Cluster analysis of backtrajectories shows that the higher aitken mode particle number concentration was observed when air parcels came from or passed by northeast part of Mt.Waliguan,with short trajectory length.High number concentration of nucleation mode was associated with air mass from clean regions,with long trajectory length.