Development of estimation method of composition of spatial suspended particulate matters by monitoring of two wavelength lidar

由于对全球变暖和空气污染的影响，悬浮颗粒物(SPM)具有重要意义。在一个城市气溶胶的案例中，我们在千叶通过采样和分析证明，元素碳(EC)在细颗粒物(直径小于2μm)中占25%，在粗颗粒物(直径大于2μm)中占9%(Yabuki等人，CLEO，2003年)。EC量的增加会带来更大的吸收，即更大的消光(散射+吸收)，这意味着更大的激光雷达比S_1(消光与后向散射系数之比)。利用气溶胶散射特性与波长的关系，仅从多波长激光雷达观测资料中就可以得到城市气溶胶S 1参数和消光系数的垂直分布。这是基于不同波长的相邻层的激光雷达信号比应该与Mie散射理论预测的值相匹配(Yabuki等人，2003年)。如果我们假设气溶胶模型和MEE(质量消光效率：消光效率与质量浓度的倒数)，那么就可以得到每个高度的浓度分布。在真实大气中，气溶胶条件由于。湿度。因此，考虑了气溶胶性质对湿度的依赖关系。将连续观测的激光雷达数据与地面气溶胶浓度数据进行了比较。结果表明，边界层中气溶胶的混合发生在短时间内(1h内)，在532 nm处的换算系数为0.08~0.1(g/m^3)/(m^&lt；-1&gt；)[MEE：为10~12.5m^2/g]。这使得如果用另一种方法测量湿度，就有可能获得城市边界层中的气溶胶空间分布：(Nofel等人，AE，2004年)。

Suspended particulate matter (SPM) is important due to the effect on global warming and air pollution. In a case of urban aerosol, we certified in Chiba the fraction of elemental carbon (EC) is 25% in fine particle (the particle diameter is less than 2 μm) and 9% in coarse particle (the size is larger than 2 μm) by sampling and analysis (Yabuki et al, CLEO 2003). The increase of EC amount brings larger absorption, i.e., larger extinction (scattering + absorption), which means larger lidar ratio S_1 (ratio of extinction to backscattering coefficient). Using the wavelength dependence of aerosol scattering property, we derived the vertical profiles of S_1 parameter and extinction coefficient of urban aerosol only from multi-wavelength lidar observation data. This is based on the lidar signal ratio of adjacent layers at different wavelengths should match the one predicted by Mie scattering theory (Yabuki et al, 2003). If we assume the aerosol model and MEE (mass to extinction efficiency: the inverse of extinction to mass concentration), then the concentration distribution at each altitude van be obtained. In real atmosphere, the aerosol condition changes due to. humidity. So humidity dependence of aerosol properties have been considered. The continuously observed lidar data ad the ground based aerosol concentration data were, compared. Then it is found that the mixture of aerosol in the boundary layer occurs in short period (within one hour) and the conversion coefficient at 532 nm is 0.08 to 0.1 (g/m^3)/(m^<-1>) [MEE : is 10 to 12.5 m^2/g]. This makes it possible to obtain the aerosol spatial profile in the urban boundary layer if the humidity is measured by another method: (Nofel et al, AE, 2004).