Abstract:

Based on the lidar detection data during a heavy air pollution process occurring in Xingtai from October 11 to 23, 2015, the change characteristics of the concentration of atmospheric pollutants, retrieved atmospheric boundary layer (PBL), aerosol optical depth (AOD) and extinction coefficient by micro pulse lidar were analyzed. The results show that the negative correlation between PBL height and PM2.5 concentration passed through the significance test when the influence of precipitation was eliminated, the lower the PBL height, the higher the PM2.5 concentration. The correlation between PBL height and PM2.5 concentration at night was better than that in the day due to less impact of human factors at night. The increase of air pollutants’ concentration could lead to significant increase of AOD and extinction coefficient, and the correlation between AOD and PM2.5 concentration in the day was better than that at night, because of variations of AOD and PM2.5 concentration caused by movement of atmospheric turbulence in the day was greater. Under the influence of precipitation and relative humidity, the air pollutants’ concentration declined, but AOD increased. The daily change of extinction coefficient at 300 m height was consistent with the ground pollutants’ concentration. Due to the diffusion capacity of pollutants near ground was stronger, a small extinction coefficient appeared near ground. Overall, with PBL height declining, AOD rising and the maximum of extinction coefficient increasing, the atmospheric quality of environment gradually deteriorated.

Key words:  lidar, atmospheric boundary layer, aerosol optical depth, extinction coefficient

摘要：

根据河北邢台市2015年10月11—23日一次重污染天气过程的激光雷达探测数据，对大气污染物浓度和雷达反演得出的大气边界层（PBL）高度、气溶胶光学厚度（AOD）和消光系数的变化进行分析。结果表明：在剔除降水因子的影响后，PBL高度对PM2.5浓度有显著影响，PBL高度越低，PM2.5浓度越高，且两者的相关性夜间好于日间；大气污染物浓度的增加会导致AOD和气溶胶消光系数的显著升高，且AOD与PM2.5浓度的相关性日间好于夜间，在降水的湿沉降效应和大气相对湿度增加的影响下，会出现大气污染物浓度下降，但AOD升高的现象；300 m高度的气溶胶消光系数与地面污染物浓度的日变化趋势较为一致，贴近地面处消光系数相对较小。整体而言，随着PBL高度下降、AOD上升和消光系数增加，环境大气质量逐步趋于恶化。

关键词: 激光雷达, 大气边界层, 气溶胶光学厚度, 消光系数