Retrieval of cloud geometrical parameters using remote sensing data

It is of great interest to investigate the properties on the cloud optical: microphysical, and geometrical parameters, in particular, of low-level marine clouds which play crucial influence on the global climate system. Top height: base height, and geometrical thickness of cloud layer are considered here as cloud geometrical parameters. These parameters are very important to retrieve, because top and base heights are the factors which govern the strength of greenhouse effect through the thermal radiation from / to cloud layer, whereas the geometrical thickness is the key parameter for the estimation of gaseous absorption in cloud layer where multiple scattering process dominates. In this study, an algorithm was developed to retrieve simultaneously cloud optical thickness, effective particle radius, top height, and geometrical thickness of cloud layer from the spectral information of visible, near infrared, thermal infrared, and oxygen A band channels. This algorithm was applied to FIRE (First ISCCP Regional Experiment, 1987) airborne data which included the above four channels and targeted at the low-level marine clouds off the coast of California in summer. The retrieved results seems to be comparable to the in situ microphysical observation although further validation studies are required for the cloud,geometrical parameters in particular.