Simultaneously retrieving cloud optical depth and effective radius for optically thin clouds

A new technique for simultaneously retrieving cloud optical depth and effective radius has been proposed. This approach is based on the angular distribution of scattered light in the forward scattering lobe of cloud drops. The angular distributions can be observed by multiple shadowband scans. Radiative transfer modeling simulations demonstrate that accuracies for cloud optical depth, effective radius, and liquid water path are 2%, 10%, and 2 gm −2 , respectively, for given possible instrument noise and uncertainties. Further, we have tested different measurement strategies and achieved consistent accuracies. This technique will provide an approach to deal with the issue of “CLOWD (cloud with low optical (water) depth).”