Summary
Since the first lidar observation of polar mesospheric clouds (PMC) in 1989 by a Na lidar at Andoya, extensive PMC observations have been made by lidars in both the northern and southern hemispheres. The lidar observations provide precise information on PMC altitudes, layer structure, and the diurnal and seasonal variations. Recently, the lidar observations at three Antarctic locations (South Pole, Davis, and Rothera) enable us to study the southern PMC properties in detail. The southern PMC exhibit some characteristics that are different from their northern counterparts, e.g., differences exist in the mean altitudes. However, there is large geophysical variability in PMC altitude and brightness in both hemispheres. Here we present a detailed comparison of the southern and northern PMC altitude distributions and brightness and their seasonal variations. The differences and similarities will be determined and possible causes for the differences will be discussed.