Rayleigh lidar studies of mesospheric inversion layers at Poker Flat Research Range, Chatanika, Alaska

Abstract

Rayleigh lidar observations at Poker Flat Research Range, Chatanika, Alaska (65°N, 213°E), have yielded density and temperature measurements from 40-80 km. These measurements have been made under clear nighttime skies since November 1997. This thesis presents a study of Mesospheric Inversion Layers (MILs) and lidar performance at Chatanika. MILs are identified and characterized in the 40-70 km altitude region on 55 of the 149 wintertime observations over two periods, November 1997-April 2005 and November 2007-March 2009, using a new detection algorithm. Investigation of the MILs compared with planetary wave activity as observed by satellite finds a strong correlation between the presence of MILs and the structure of the planetary waves. These two periods are marked by strong planetary wave activity and sudden stratospheric warming events. MILs are found to occur more frequently than previously reported at Arctic sites, but less frequently than at lower latitudes. In spring 2012 the existing lidar system was extended by incorporating a larger aperture telescope and higher power laser and field trials were conducted. The results from these field trails are presented and the ability of the new lidar system to extend the scope of future studies at Chatanika is assessed.