基于激光云高仪探测污染天气边界层高度

Observation of atmospheric boundary layer height of pollution weather with lidar ceilometer

利用2016年10月北京市大兴CL51云高仪后向散射数据,分别采用梯度法和小波协方差法计算了边界层高度。分析了晴空和霾污染天气边界层高度的差异及影响因素。结果表明,两种方法计算的边界层高度一致性较好。晴空和霾污染天气边界层高度具有不同特征,在霾污染天气,由于大气中污染物削弱了到达地表的太阳辐射,地表没有足够的热量使边界层发生明显抬升,边界层高度维持在较低的高度。晴空天气,由于太阳辐射对地面的增温,边界层高度在正午前后有明显的抬升,边界层高度较高且日变化较明显。边界层高度与地面PM_(2.5)、PM_(10)、CO和黑碳气溶胶等污染物浓度呈负相关关系。

The atmospheric boundary layer height(ABLH)was calculated by the lidar ceilometer based on the data of Vaisala CL51 ceilometer observed in October 2016 by the Beijing Daxing station.Both the gradient method and the wavelet covariance method were adopted.The atmospheric boundary layer height difference and its influence factors in sunny and haze conditions were analyzed.The results showed that there was no significant difference in ABLH by the two methods.The boundary layer height had different characteristics under different weather conditions.In the case of haze pollution,due to the absorption and scattering of the solar radiation by pollutants in the atmosphere,there was less solar radiation reached the earth surface,the ABLH was lower because of the less heat.While in sunny days,because of the warming of the earth by the solar radiation,the ABLH was higher than that of haze days,and the daily variation of ABLH was more obvious.The ABLH was negatively correlated with the concentrations of PM_(2.5),PM_(10),CO,black carbon aerosol and other pollutants on the ground.