进行低空探测的机载激光雷达消光系数反演存在着标定点选取和标定值确定两大困难。Fernald迭代后向积分法能够在不利用其它辅助设备的情况下,找到进行低空探测机载激光雷达消光系数反演所需的标定点和标定值。利用Fernald迭代后向积分法...进行低空探测的机载激光雷达消光系数反演存在着标定点选取和标定值确定两大困难。Fernald迭代后向积分法能够在不利用其它辅助设备的情况下,找到进行低空探测机载激光雷达消光系数反演所需的标定点和标定值。利用Fernald迭代后向积分法和Pal met al.(2002)方法分别对青岛机载激光雷达实验数据进行处理,得到的两条消光系数廓线基本吻合。定量分析显示:利用Fernald迭代后向积分法进行机载激光雷达消光系数反演时,激光雷达比对消光系数反演结果影响很大;标定点的消光系数值及迭代判据的取值对机载激光雷达消光系数反演的结果影响较小。Fernald迭代后向积分法为不用其它辅助设备进行低空探测的机载激光雷达消光系数反演提供了一种可行的范例。展开更多
Observation of optical properties of atmospheric aerosols, especially their behavior near the surface level, is indispensable for better understanding of atmospheric environmental conditions. Concurrent observations o...Observation of optical properties of atmospheric aerosols, especially their behavior near the surface level, is indispensable for better understanding of atmospheric environmental conditions. Concurrent observations of ground-based instruments and satellite-borne sensors are useful for attaining improved accuracy in the observation of relatively wide area. In the present paper, aerosol parameters in the lower troposphere are monitored using a plan position indicator (PPI) lidar, ground-sampling instruments (a nephelometer, an aethalometer, and optical particle counters), as well as a sunphotometer. The purpose of these observations is to retrieve the aerosol extinction coefficient (AEC) and aerosol optical thickness (AOT) simultaneously at the overpass time of Landsat-8 satellite. The PPI lidar, operated at 349 nm, provides nearly horizontal distribution of AEC in the lower part of the atmospheric boundary layer. For solving the lidar equation, the boundary condition and lidar ratio are determined from the data of ground sampling instruments. The value of AOT, on the other hand, is derived from sunphotometer, and used to analyze the visible band imagery of Landsat-8 satellite. The radiative transfer calculation is conducted using the MODTRAN code with the original aerosol type that has been determined from the ground sampling data coupled with the Mie scattering calculation. Reasonable agreement is found between the spatial distribution of AEC from the PPI lidar and that of AOT from the blue band (band 2) of Landsat-8. The influence of AOT on the values of apparent surface reflectance is also discussed.展开更多
文摘进行低空探测的机载激光雷达消光系数反演存在着标定点选取和标定值确定两大困难。Fernald迭代后向积分法能够在不利用其它辅助设备的情况下,找到进行低空探测机载激光雷达消光系数反演所需的标定点和标定值。利用Fernald迭代后向积分法和Pal met al.(2002)方法分别对青岛机载激光雷达实验数据进行处理,得到的两条消光系数廓线基本吻合。定量分析显示:利用Fernald迭代后向积分法进行机载激光雷达消光系数反演时,激光雷达比对消光系数反演结果影响很大;标定点的消光系数值及迭代判据的取值对机载激光雷达消光系数反演的结果影响较小。Fernald迭代后向积分法为不用其它辅助设备进行低空探测的机载激光雷达消光系数反演提供了一种可行的范例。
文摘Observation of optical properties of atmospheric aerosols, especially their behavior near the surface level, is indispensable for better understanding of atmospheric environmental conditions. Concurrent observations of ground-based instruments and satellite-borne sensors are useful for attaining improved accuracy in the observation of relatively wide area. In the present paper, aerosol parameters in the lower troposphere are monitored using a plan position indicator (PPI) lidar, ground-sampling instruments (a nephelometer, an aethalometer, and optical particle counters), as well as a sunphotometer. The purpose of these observations is to retrieve the aerosol extinction coefficient (AEC) and aerosol optical thickness (AOT) simultaneously at the overpass time of Landsat-8 satellite. The PPI lidar, operated at 349 nm, provides nearly horizontal distribution of AEC in the lower part of the atmospheric boundary layer. For solving the lidar equation, the boundary condition and lidar ratio are determined from the data of ground sampling instruments. The value of AOT, on the other hand, is derived from sunphotometer, and used to analyze the visible band imagery of Landsat-8 satellite. The radiative transfer calculation is conducted using the MODTRAN code with the original aerosol type that has been determined from the ground sampling data coupled with the Mie scattering calculation. Reasonable agreement is found between the spatial distribution of AEC from the PPI lidar and that of AOT from the blue band (band 2) of Landsat-8. The influence of AOT on the values of apparent surface reflectance is also discussed.
