Probing the Boundary Layer of Neutral Atmosphere Using a Unique Na Lidar System

Dr. Titus Yuan
Department of Physics
Utah State University

The mesopause region (80-110 km altitude) covers the boundary between mesosphere and thermosphere, where various coupling processes occur between the atmospheric molecules and charged particles. It is also the region where meteorological processes in the troposphere and stratosphere start to have significant impacts on the ionosphere. These interactions are highly important for understanding the whole atmosphere system, and critical for space physics, space weather studies. However, little is known about this part of the atmosphere due to challenges to conduct in situ measurement. In this presentation, I will introduce a unique and “powerful” lidar system that can conduct mesopause region observations in full diurnal cycle, followed by some ongoing geophysical sciences that are enabled by these measurements. This lidar system, by taking advantage the naturally existed Na layer in the upper atmosphere, measures the Doppler broadening and Doppler shift of the fluorescence spectrum from these neutral Na atoms and, thus, provides high resolution measurements of the mesopause region temperature and wind. Locating at Utah State University, this lidar system, coupled with other remote sensing instruments, especially satellite observations, has reveals unprecedented results that have considerably improved our understanding of this boundary layer between the atmosphere and space.