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

Abstract

Polar mesospheric clouds (PMCs) were observed above the geographic South Pole by all Fe Boltzmann temperature lidar from 11 Dec 99 to 24 Feb O0. 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 τ 0.12 × 10-9 m-1sr-1, 3.61 τ 0.22 × 10-6 sr-1, 85.49 τ 0.09 km, and 0.71 τ 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.