基于车载激光雷达走航观测的石家庄及周边地区气溶胶空间分布特征

Spatial distribution characteristics of aerosols in Shijiazhuang and its surroundings based on mobile lidar cruise observations

运用微脉冲激光雷达对气溶胶的垂直分布特征进行遥感观测逐渐普及,但传统观测往往局限于固定站点,无法反映区域内气溶胶整体分布情况。该研究以石家庄市为中心,运用车载便携式激光雷达对城市内部及其周边区域开展大气环境立体走航观测,绘制出气溶胶三维空间分布信息。结果表明:(1)该地区大气污染受地形影响,西侧太行山阻断了汾河盆地的气溶胶输送,气溶胶于太行山东麓的山前低地汇聚,向东至广阔的平原扩散开;(2)石家庄东北至南部形成气溶胶汇聚区,其聚集程度由东北向南逐渐增强,此外太行山与燕山走向的西北部分的清洁区与污染汇聚区有明显分界;(3)石家庄市区外环线的气溶胶垂直扩散能力强、颗粒物不规则度较高,可能存在多源混合,市区气溶胶聚集高度的空间方位差异可能由污染源分布的不均衡所致。

Micro Pulse Lidar(MPL)has been widely used in the measurement of the vertical distribution of aerosols,while it is usually set to a fixed station and cannot observe the whole spatial distribution.In this study,the Mini MPL integrated in the car was used to carry out cruise observations of Shijiazhuang and its surrounding areas,and the continuous three-dimensional spatial distribution of aerosols in the area was mapped out.Results revealed that:(1)the air pollution in this area is influenced by the topography,the west Taihang Mountains block the transport of aerosols in the Fen River Basin,aerosols converge in the lowlands in front of east Taihang Mountains and spread eastward to the vast plains;(2)the aerosols convergence zone is formed from the northeast to the south of Shijiazhuang,the concentration of air pollutants gradually increases from the northeast to the south,in addition,there is a clear boundary between the polluted zone and the clean zone that in the northwest part of the Taihang Mountains and Yanshan Mountains;(3)the strong vertical dispersion of aerosols and high irregularity of particulate matter in the outer space of Shijiazhuang may result from multi-source mixing,and the differences of the aerosols height in the four directions may be caused by the uneven distribution of pollution sources.