北京夏季典型臭氧污染分布特征及影响因子

为研究北京地区O3分布特征及其影响因子,利用AML-3车载式大气环境污染激光雷达系统(下称AML-3)对北京地区2011年5月7日-6月9日的ψ(O3)进行观测.通过AML-3自带的污染物地面观测系统和差分吸收激光雷达,分析近地面、高空ψ(O3)时空分布特征,并将ψ(O3)与温度、风速及风向3个气象要素进行相关分析.结果表明:近地面ψ(O3)日变化明显,06:00左右为低谷,下午14:00左右达到峰值.高空ψ(O3)的空间分布很不均匀,上层气流易使O3富集层向下输送造成污染,同时稳定边界层对大气扩散的不利影响也是形成O3污染的重要原因.ψ(O3)的日变化趋势与温度的日变化趋势呈显著正相关,R(相关系数)为0.74;上下层湍流交换使风速与近地面ψ(O3)呈正相关,而水平扩散使二者呈负相关；通过分析风向的分布规律发现,东北风易造成北京地区O3污染.

Characteristics of Typical Ozone Pollution Distribution and Impact Factors in Beijing in Summer

The mobile AML-3 lidar system was used to monitor the ozone distribution and impact factors in Beijing from 7^th May to 9^th June, 2011. The data from the Differential Absorption Lidar were analyzed and pollutant monitoring systems were created in this study. The vertical distributions of the ground ozone were observed at different periods in the daytime, and the correlations between ozone concentrations and meteorological elements (e.g., temperature, wind speed and wind direction) were analyzed. The results showed a significant difference of the near surface ozone concentrations between different monitored periods. The peak value appeared at 14:00 while the valley value occurred at 06:00. The ozone concentration distribution in the upper layer is non-uniform, since the airflow in the upper layer can easily transport pollutants to the lower layer and cause ozone enrichment in the atmospheric boundary layer. The negative effect on the atmosphere diffusion caused by the stabile boundary layer is the main reason for ozone pollutions. The ozone diurnal trends and the diurnal temperature trend have a very significant positive relationship with the correlation coefficient about 0.74. Turbulence caused a positive effect on wind speed and ozone concentration while horizontal diffusion caused a negative effect on wind speed and ozone concentration. The research on wind direction effects showed that the wind came from northeast side has more significant impact on Beijing''s ozone pollution.