Researchers use the Atmospheric Lidar Observatory to couple lower portion of the atmosphere with the upper mesosphere and lower thermosphere. Based on lidar observations of mid-stratosphere to lower thermosphere temperatures, this emphasizes the transition region between the upper mesosphere and lower thermosphere. Using a much larger telescope, they're able to precisely determine Rayleigh-scatter temperatures and time resolution in the upper mesosphere, and extend maximum altitude above 100 kilometers. Nightly averaged lidar temperatures are used to study seasonal variations in the transition region, especially (1) the mesopause altitude and structure near 87 and 102 kilometers, (2) the relationship between high-altitude summer inversion layers (by Rayleigh lidar) and an inversion layer near 90 kilometers (by sodium lidar), (3) the behavior of vertical wave-like appearance of mesospheric inversion layers to higher altitudes. These nightly temporal variations (or their monthly averages) examine time-varying phenomena, such as tides and downward/upward phase progression of mesospheric inversion layers.
