Title :
Retrieving Optical Depths and Lidar Ratios for Transparent Layers Above Opaque Water Clouds From CALIPSO Lidar Measurements
Author :
Hu, Yongxiang ; Vaughan, Mark ; Liu, Zhaoyan ; Powell, Kathleen ; Rodier, Sharon
Author_Institution :
NASA Langley Res. Center, Hampton
Abstract :
For measurements that are made by the CALIPSO lidar, the layer-integrated attenuated backscatter of opaque water clouds gamma´water,O can be accurately estimated for those cases for which there is no overlying aerosol or cloud layer. When transparent overlying layers of clouds or aerosols are present, the layer-integrated attenuated backscatter that is measured for the water cloud is reduced by a factor that is equal to the two-way transmittance of the upper layer. Because the layer-integrated depolarization ratio can be used to obtain an independent estimate of gamma´water,O, we can subsequently derive both the optical depth and an estimate of the layer-averaged lidar ratio of the overlying layer.
Keywords :
aerosols; atmospheric optics; atmospheric precipitation; atmospheric techniques; backscatter; clouds; optical radar; remote sensing by laser beam; CALIPSO lidar measurement; aerosols; laser radar; layer-integrated attenuated backscatter; layer-integrated depolarization ratio; opaque water clouds; optical depth retrieval; transparent layers; Aerosols; Atmospheric measurements; Attenuation measurement; Backscatter; Clouds; Infrared sensors; Laser radar; Optical attenuators; Optical polarization; Optical sensors; Aerosols; algorithms; clouds; laser radar;
Journal_Title :
Geoscience and Remote Sensing Letters, IEEE
DOI :
10.1109/LGRS.2007.901085