Long-term variations of aerosol optical properties over Wuhan with polarization lidar
Long-term variations of aerosol optical properties over Wuhan with polarization lidar
复制标题
DOI：
10.1016/j.atmosenv.2021.118508
复制
发表时间：
2021-06-05
影响因子：
5
通讯作者：
Zhang, Yunfei
中科院分区：
文献类型：
--
作者：
Yin, Zhenping;Yi, Fan;Zhang, Yunfei
气溶胶严重影响全球和区域气候系统以及公众健康。我们于2010年10月至2020年6月在武汉（30.53-N，114.37-E）进行了激光雷达测量，并使用自动激光雷达处理算法分析了大量数据集，以研究气溶胶的长期变化。自2010年以来，激光雷达得出的532 nm处的总气溶胶光学厚度（AOD）显示出-0.049的年际减少。与世界其他特大城市的AOD相比，武汉的AOD下降幅度最大。分离边界层和自由对流层的气溶胶光学厚度贡献后，发现两者的气溶胶光学厚度的变化规律不同，自由对流层和边界层的气溶胶光学厚度的年下降率分别为-0.009和-0.044，说明80%以上的气溶胶光学厚度的下降与局地排放的减少有关。此外，在COVID-19封锁前，BL AOD总是大于FT AOD。然而，这一关系随后被逆转，BL AOD的最低值为0.125，是2010年以来的最低值，仅为同期FT AOD的一半。这一特征证实了COVID-19封锁对人类活动和当地排放的强烈影响。这些研究结果有助于加深我们对区域气溶胶对污染控制的响应以及气溶胶对区域气候的直接影响的认识。
Aerosols greatly impact the global and regional climate system and public health. We conducted lidar measurements at Wuhan (30.53-N, 114.37-E) from October 2010 to June 2020 and analyzed the massive dataset with an automatic lidar processing algorithm, to investigate the long-term variations of aerosols. Lidar-derived total aerosol optical depth (AOD) at 532 nm shows an interannual decrease of -0.049 since 2010. Compared with AODs in other megacities worldwide, the AOD for Wuhan shows the largest decrease rate. After separating AOD contributions from boundary layer (BL) and free troposphere (FT), different evolution patterns are revealed with AOD decrease rates of -0.009 and -0.044 per year for FT and BL, respectively, which indicates more than 80% of AOD decrease are associated with reductions of local emissions. In addition, BL AOD was always larger than FT AOD before COVID-19 lockdown. However, this relation was conversed thereafter, with the lowest value of 0.125 for BL AOD since 2010, which is only the half of FT AOD within the same period. This feature corroborates strong influences of COVID-19 lockdown on human activities and local emissions. These findings can improve our understandings of regional aerosol responses to pollution controls and aerosol direct impacts on regional climate.