Geometrical and optical parameters of Tropopause Cirrus Clouds in the Southern Hemisphere

We analyzed the mean optical properties of southern hemisphere midlatitude tropopause cirrus, such as optical depth, extinction coefficient and lidar ratio using lidar observations and calculations based on the Klett's method. The lidar signals show that the tropopause cirrus have thicknesses ranging between 1.5-4 km with a mean extinction coefficient and lidar ratio of about 0.15 km$^{-1}$ and 20 sr for cirrus measured in 2001-2006. The values reveal that the parameters are close to those reported from other midlatitudes researches. The temperature dependence of the cirrus extinction/optical depth has been represented in order to compare with recently published papers. Comparison of the results of the present analysis with other tropical and midlatitude cirrus studies reveals that these cirrus have remarkable characteristics that may be related to their crystal composition, size, longevity and with the prevailing dynamical process at this southern midlatitude and thus with the geographical and meteorological conditions.