In June–July 2012, observations were carried out using the recently upgraded, large-aperture, Rayleigh-scatter lidar system located at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University, in Logan, UT (41.7 N, 111.8 W). This time period was significant because it enabled us to observe the annual temperature minimum in the upper mesosphere-lower thermosphere region. The data collected during the campaign were analyzed for temperatures between ~70–109 km. The results above ~95 km are the first obtained with a Rayleigh-scatter lidar, extending the technique well into the lower thermosphere. A great deal of variability from night-to-night is evident in these temperature profiles and in the mesopause altitude. The profiles also show considerable wave activity from large amplitude waves. The temperatures are compared to those from the MSISe90 model and from the 11-year ALO temperature climatology. This new capability for the ALO Rayleigh lidar, like any new observational capability, opens the potential for new discoveries in this hard-to-observe region.
Available at: http://works.bepress.com/vincent_wickwar/125/