An intercomparison of AOD-converted PM2.5 concentrations using different approaches for estimating aerosol vertical distribution
An intercomparison of AOD-converted PM2.5 concentrations using different approaches for estimating aerosol vertical distribution
复制标题
使用不同方法估算气溶胶垂直分布的 AOD 转换 PM2.5 浓度的相互比较
DOI：
10.1016/j.atmosenv.2017.07.054
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发表时间：
2017
影响因子：
5
通讯作者：
Shen Chuanyang
中科院分区：
文献类型：
--
作者：
Su Tianning;Li Jing;Li Chengcai;Lau Alexis Kai-Hon;Yang Dongwei;Shen Chuanyang
由于地面PM2. 5监测站点的空间覆盖有限，卫星气溶胶光学厚度（aerosol optical depth，AOD）产品已被广泛应用于全球不同地区的地面PM2. 5监测。将气溶胶光学厚度转换为PM2.5的一个主要困难和不确定性来源是确定气溶胶的垂直分布，通常用边界层高度（BLH）表示。本文利用香港元朗超级站的长期多源资料，对不同方法估算气溶胶垂直分布在AOD-PM2. 5转换过程中的性能进行了评价。分别利用激光雷达、探空仪和MERRA再分析资料的气溶胶垂直分布和BLH产品的月气候学资料，将气溶胶光学厚度转换为地面气溶胶消光系数。建立了季节性经验吸湿增长函数，将气溶胶消光转化为干PM2.5质量浓度。结果表明，不同的垂直分布估计方法可以有很大的变化对转换后的PM2. 5浓度的影响。使用激光雷达衍生的BLHs显示出最好的协议，与相关系数为0.73，检索和观测之间的相对偏差为30.6%。由于连续激光雷达测量是不可用的大部分地区，气溶胶结构的气候模式和无线电探空仪派生BLH被认为是合适的替代品的相关系数为1.00.6，并大大优于使用BLH来自再分析数据的结果。升高的气溶胶层似乎是不确定性的主要来源，并导致高估卫星结果，特别是在春季和夏季。
Due to the limited spatial coverage of surface PM2.5monitoring sites, satellite AOD (aerosol optical depth) products have been widely used to estimate surface PM2.5in different parts of the world. A major difficulty as well as source of uncertainty in converting AOD to PM2.5is the determination of aerosol vertical distribution, usually represented by the boundary layer height (BLH). In this study, we evaluate the performance of different approaches of estimating aerosol vertical distributions in the AOD-PM2.5conversion process, using long-term and multi-source data acquired at a super station, Yuen Long, Hong Kong. The monthly climatology of aerosol vertical distribution and BLH products derived from lidar, radiosonde, and MERRA reanalysis data are respectively applied for converting AOD to surface aerosol extinction coefficients. Seasonal empirical hygroscopic growth functions are constructed to convert aerosol extinction to dry PM2.5mass concentration. Results indicate that different vertical distribution estimation approaches can have highly varying effect on the converted PM2.5concentration. Using lidar-derived BLHs shows the best agreement, with a correlation coefficient of 0.73 and a relative bias of 30.6% between retrievals and observations. Since continuous lidar measurements are not available for most regions, the climatology pattern of aerosol structure and radiosonde-derived BLHs are found to be suitable alternatives with a correlation coefficient of ∼0.6, and considerably outperform the results using BLHs derived from reanalysis data. Elevated aerosol layers appear to be the major source of uncertainty and result in an overestimate of satellite results, especially during the spring and summer seasons.