静稳气象条件下的细颗粒物垂直结构特征研究

Study on the characteristics of PM_(2.5) vertical structure in calm and stable weather condition

基于Mie散射激光雷达探测数据及地面细颗粒物(PM2.5)观测资料和常规气象观测资料,利用logistic曲线计算了混合层顶高度,进一步分析了边界层内混合层以上区域大气消光系数廓线在静稳气象条件下的垂直结构。结果表明:(1)通过高斯误差函数构造数学模型可以将边界层内混合层以上区域进一步细分;(2)成都在轻度污染、中度污染、重度污染和严重污染4类静稳气象条件下大气消光系数廓线自下而上一致呈现出混合层、缓降层、过渡层和自由大气的垂直结构特征;(3)分析一次典型灰霾过程发现,PM2.5对混合层顶高度有显著影响,两者之间存在显著的负相关关系,而对缓降层顶高度和过渡层顶高度影响不大。

Based on Mie scattering radar detection data,near-surface PM2.5 data and meteorological observation data,mixing layer height was calculated using the logistic curve,and the vertical structure characteristics of the atmospheric extinction coefficient profile above mixing layer in bounding layer were further analyzed under calm and stable weather condition.Results showed that:(1)it was feasible that the layer above mixing layer in bounding layer could be further divided through establishing maths model using Gaussian error function.(2)The atmospheric extinction coefficient profile could be divided into mixing layer,slow descent layer,transition layer and free atmosphere under calm and stable weather conditions of light pollution,medium pollution,heavy pollution and severe pollution in Chengdu from bottom to top.(3)A typical haze episode analysis showed that PM2.5 had significant negative effect on mixing layer head height,but little on slow descent layer head height and transition layer head height.