基于激光雷达分析一次重霾过程混合层高度

摘要

In order to deepen the understanding of the mixed layer height in winter, a heavy haze episode from January 23 to February 4, 2014 in Chengdu was observed by Mie scattering lidar. Based on the backscatter coefficient observed from Mie scattering lidar, the mixed layer height was calculated by SBH99 algorithm, and then analysis its evolution characteristics and its relationship with meteorological factors. The main conclusions are summarized as following:According to a comparative analysis of mixed layer height indicated by lidar and stratification curve, results showed a better consistency, whose correlation coefficient R was 0. 893 4. The average height of mixed layer was low during this heavy haze episode, which was about 378 m; after the occurrence of haze, the mixed layer height significantly decreased with little change in diurnal variation, and the gap between maximum and minimum of mixed layer was reduced. The development of the mixed layer height had a positive correlation with the change of air temperature, and a negative correlation with relative humidity.%为深化对冬季重霾天气大气混合层高度的认识，利用Mie散射激光雷达观测了成都市2014年1月23日至2月4日一次典型重霾天气过程。基于Mie散射激光雷达探测获取的后向散射系数，使用SBH99算法计算了该过程的混合层高度，并系统分析其演变特征及其与气象因子的关系，研究结果表明：将激光雷达探测的混合层高度与探空曲线表征出的混合层高度进行对比分析，结果显示两者具有较好的一致性，相关系数为0.8934；此次重霾过程中，混合层高度平均值较低，约378 m；霾天气发生后，混合层高度显著下降，并且混合层高度的最大值与最小值之间差距缩小，日变化波动不明显；混合层高度的发展与空气温度的变化趋势呈正相关关系，与相对湿度呈负相关关系。