Automated method for lidar determination of cloud-base height and vertical extent

An algorithm for the automated analysis of lidar cloud returns has been developed as part of the Experimental Cloud Lidar Pilot Study program. This automated method determines the cloud-base and cloud-top heights as well as the altitude of the maximum return signal. A large body of cloud data that were obtained at 532 and 1064 nm with a Nd:YAG lidar have been evaluated and it has been found that the algorithm can handle the wide range of complex cloud situations encountered. The need for a more careful definition of the cloud-base height and cloud-top height is described and discussed in relation to the existing measurements with rotating beam and laser ceilometers.