Polar Stratospheric Cloud (PSC) classification using LIDAR measurements from the recent SAGE III Ozone Loss and Validation Experiment (SOLVE)

Lidar measurements from the recent SAGE III Ozone Loss and Validation Experiment (SOLVE) have been used to identify the number of classes of Polar Stratospheric Clouds (PSCs) and their corresponding characteristics. The backscatter lidar, flown aboard a DC8 aircraft, measures profiles of backscatter at 532 nm and 1064 nm, and depolarization at 532 nm. These data along with the color ratio were used to categorize PSCs using a clustering algorithm. For each group or cluster, the central values or medoids describe the optical characteristics of the clouds. For this preliminary study, five such groups were determined with medoid scattering ratios of 1.13, 11.90, 47.68, 71.07, and, 88.96 at 532 nm. The mean quality index of 0.82 for the five groups shows that the clusters are sufficiently distinct from each other.