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Estimation of Particle Mass Concentration from Lidar Measurement

Vertical distribution of particle mass concentrations was estimated from 8-year elastic-backscatter lidar and sky radiometer data, and from ground-level PM10 concentrations measured in Seoul. Lidar ratio and mass extinction efficiency were determined from aerosol optical depth (AOD) and ground-level PM10 concentrations, which were used as constraints to estimate particle mass concentration. The mean lidar ratio (with standard deviation) and mass extinction efficiency for the entire 8-year study period were $60.44{\pm}23.17$ sr and $3.69{\pm}3.00m^2g^{-1}$, respectively. The lidar ratio did not vary significantly with the ${\AA}ngstr{\ddot{o}}m$ exponent (less than ${\pm}10%$); however, the mass extinction efficiency decreases to $1.82{\pm}1.67m^2g^{-1}$ (51% less than the mean value) when the ${\AA}ngstr{\ddot{o}}m$ exponent is less than 0.5. This result implies that the particle mass concentration from lidar measurements can be underestimated for dust events. Seasonal variation of the particle mass concentration estimated from lidar measurements for the boundary layer, was quite different from ground-level PM10 measurements. This can be attributable to an inhomogeneous vertical distribution of aerosol in the boundary layer.