First lidar observations of polar mesospheric clouds and Fe temperatures at McMurdo (77.8S, 166.7E), Antarctica

摘要

We report the first lidar observations of polar mesospheric clouds (PMCs) and temperatures made with an Fe Boltzmann lidar at McMurdo, Antarctica in summer 2010-2011. Eighty-five hours of PMCs were observed between 21 Dec 2010 and 15 Feb 2011, giving an overall occurrence frequency of 29.9%. The mean PMC centroid altitude is 84.59 0.17 km, confirming previous reports that clouds in the Southern Hemisphere are ～1 km higher than in the North. By combining the McMurdo (77.8S) observations with those obtained at the South Pole (90S) and Rothera (67.5S), we find that the mean PMC altitude increases with increasing latitude with a statistically significant ascending rate of 40 3 m/deg. A negative correlation is found between the daily-mean temperatures at 90 km and PMC brightness. The observations provide direct evidence that the cold phase of wave-induced temperature oscillations facilitates PMC formation and Fe depletion, supporting previous modeling results.