A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-...A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-in amplification technique adopted,the sensitivity of the instrument is high enough to conduct direct sun moon and twilight measurement for several atmospheric species and the degree of polarization and intensity observation for sky light. From measured results, the total column abundance of atmospheric species and the optical characteristics of aerosol can be retrieved. In this paper, the daily averaged column abundance of O_3 measured in Beijing by direct sun was compared with Dobson spectrophotometer nearby. The two did not show significant difference.展开更多
The sky radiance and degree of polarization with multiple scattering process considered were calculated in this paper by solving vector form radiative transfer equation iteratively. Numerical experiment for simultaneo...The sky radiance and degree of polarization with multiple scattering process considered were calculated in this paper by solving vector form radiative transfer equation iteratively. Numerical experiment for simultaneously retriving the size distribution (SD) and the complex refractive index (CRI) of aerosol particle was conducted with the degree of polarization of skylight (DPS) and the library method used. It is shown from the results that the real part of CRI is always sensitive to DPS. But situation is somewhat complicated for the imaginary part of CRI. Therefore, it is expected that the real part of CRI can be retrieved from DPS and its imaginary part should be retrieved as the particle is large in size. In this paper, seven sets of DPS measurements on 6 January, 1990 in Beijing were given and the optical characteristics of aerosol were retrieved.展开更多
文摘A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-in amplification technique adopted,the sensitivity of the instrument is high enough to conduct direct sun moon and twilight measurement for several atmospheric species and the degree of polarization and intensity observation for sky light. From measured results, the total column abundance of atmospheric species and the optical characteristics of aerosol can be retrieved. In this paper, the daily averaged column abundance of O_3 measured in Beijing by direct sun was compared with Dobson spectrophotometer nearby. The two did not show significant difference.
文摘The sky radiance and degree of polarization with multiple scattering process considered were calculated in this paper by solving vector form radiative transfer equation iteratively. Numerical experiment for simultaneously retriving the size distribution (SD) and the complex refractive index (CRI) of aerosol particle was conducted with the degree of polarization of skylight (DPS) and the library method used. It is shown from the results that the real part of CRI is always sensitive to DPS. But situation is somewhat complicated for the imaginary part of CRI. Therefore, it is expected that the real part of CRI can be retrieved from DPS and its imaginary part should be retrieved as the particle is large in size. In this paper, seven sets of DPS measurements on 6 January, 1990 in Beijing were given and the optical characteristics of aerosol were retrieved.
