Lidar observations of polar mesospheric clouds at South Pole: Seasonal variations

Polar mesospheric clouds (PMCs) were observed above the geographic South Pole by an Fe Boltzmann temperature lidar from 11 Dec 99 to 24 Feb 00. During this 76-day period 297 h of observations were made on 33 different days and PMCs were detected 66.5% of the time. The mean PMC peak backscatter ratio, peak volume backscatter coefficient, total backscatter coefficient, layer centroid altitude, and layer rms width are 50.59 +/- 2.33, 2.70 +/- 0.12x10(-9) m(-1)sr(-1), 3.61 +/- 0.22x10(-6) sr(-1), 85.49 +/- 0.09 km, and 0.71 +/- 0.03 km, respectively The PMCs are highest near summer solstice when upwelling over the pole is strongest. The altitudes are 2-4 km higher than that typically observed elsewhere, including the North Pole. After solstice the mean altitudes decreases by about 64 m/day as the upwelling weakens.