With the method of differential optical absorption spectroscopy （DOAS）, average concentrations of aerosol particles along light path were measured with a flashlight source in Chiba area during the period of one mont...With the method of differential optical absorption spectroscopy （DOAS）, average concentrations of aerosol particles along light path were measured with a flashlight source in Chiba area during the period of one month. The optical thickness at 550 nm is compared with the concentration of ground-measured suspended particulate matter （SPM）. Good correlations are found between the DOAS and SPM data, leading to the determination of the aerosol mass extinction efficiency （MEE） to be possible in the lower troposphere. The average MEE value is about 7.6m^2.g^-1 , and the parameter exhibits a good correlation with the particle size as determined from the wavelength dependence of the DOAS signal intensity.展开更多
There are two widely used radiative models without consideration of aerosol inhomogeneity for satellite remote sensing application, the Homogeneous Model and the Two-layer Model with aerosol in the lower layer. In thi...There are two widely used radiative models without consideration of aerosol inhomogeneity for satellite remote sensing application, the Homogeneous Model and the Two-layer Model with aerosol in the lower layer. In this paper, effects of the aerosol vertical inhomogeneity on upwelling radiance and satellite remote sensing of surface reflectance are analyzed through numerical simulations by using two models. As shown in the simulations by using 24 representative aerosol models, there is often a considerably large error in upwel-ling radiance calculated by two models (Homogeneous and Two-layer) for the short wavelength channel with strong molecular scattering, owing to the difference between molecular and aerosol scattering proper-ties. For the long wavelength channel, the error is small if aerosol optical parameters are less variable with height, but it could also be significant if there are aerosol layers with different scattering phase functions and single scattering albedo. The radiance errors by the Homogeneous Model and the Two-layer Model can be up to 31.4% and 31.5% for the clean atmosphere, and in case of turbid atmosphere 67.8% and 59.2%, respectively. The radiance error could result in a large uncertainty of surface reflectance retrievals, especially for the short wavelength channel and the strongly absorbing aerosol. For the turbid atmosphere with strong-ly absorbing aerosol, the Homogeneous Model and the Two-layer Model are not suitable for atmospheric correction application. Key words Satellite remote sensing - Aerosol inhomogeneity - Surface reflectance - Radiance展开更多
Continuous data of aerosol optical thickness monitored using differential optical absorption spectroscopy （DOAS） are correlated with the concentration of ground-measured suspended particulate matter （SPM）. A high ...Continuous data of aerosol optical thickness monitored using differential optical absorption spectroscopy （DOAS） are correlated with the concentration of ground-measured suspended particulate matter （SPM）. A high correlation is found between the DOAS and the ground SPM data, making it possible to calculate the mass extinction efficiency of the aerosols in the atmosphere. It is found that the value of mean mass extinction efficiency （MEE） varies over a range of 2.6-13.7 m^2 g^-1, with smaller and larger values occurring for size distributions dominated by coarse and fine particles, respectively.展开更多
基金Project supported by National Natural Science Foundation of China （Grant No 10274080）.
文摘With the method of differential optical absorption spectroscopy （DOAS）, average concentrations of aerosol particles along light path were measured with a flashlight source in Chiba area during the period of one month. The optical thickness at 550 nm is compared with the concentration of ground-measured suspended particulate matter （SPM）. Good correlations are found between the DOAS and SPM data, leading to the determination of the aerosol mass extinction efficiency （MEE） to be possible in the lower troposphere. The average MEE value is about 7.6m^2.g^-1 , and the parameter exhibits a good correlation with the particle size as determined from the wavelength dependence of the DOAS signal intensity.
文摘There are two widely used radiative models without consideration of aerosol inhomogeneity for satellite remote sensing application, the Homogeneous Model and the Two-layer Model with aerosol in the lower layer. In this paper, effects of the aerosol vertical inhomogeneity on upwelling radiance and satellite remote sensing of surface reflectance are analyzed through numerical simulations by using two models. As shown in the simulations by using 24 representative aerosol models, there is often a considerably large error in upwel-ling radiance calculated by two models (Homogeneous and Two-layer) for the short wavelength channel with strong molecular scattering, owing to the difference between molecular and aerosol scattering proper-ties. For the long wavelength channel, the error is small if aerosol optical parameters are less variable with height, but it could also be significant if there are aerosol layers with different scattering phase functions and single scattering albedo. The radiance errors by the Homogeneous Model and the Two-layer Model can be up to 31.4% and 31.5% for the clean atmosphere, and in case of turbid atmosphere 67.8% and 59.2%, respectively. The radiance error could result in a large uncertainty of surface reflectance retrievals, especially for the short wavelength channel and the strongly absorbing aerosol. For the turbid atmosphere with strong-ly absorbing aerosol, the Homogeneous Model and the Two-layer Model are not suitable for atmospheric correction application. Key words Satellite remote sensing - Aerosol inhomogeneity - Surface reflectance - Radiance
文摘Continuous data of aerosol optical thickness monitored using differential optical absorption spectroscopy （DOAS） are correlated with the concentration of ground-measured suspended particulate matter （SPM）. A high correlation is found between the DOAS and the ground SPM data, making it possible to calculate the mass extinction efficiency of the aerosols in the atmosphere. It is found that the value of mean mass extinction efficiency （MEE） varies over a range of 2.6-13.7 m^2 g^-1, with smaller and larger values occurring for size distributions dominated by coarse and fine particles, respectively.
