CEDAR Frontiers: Investigating the Thermosphere with Resonance Lidar Richard L. Collins (rlc@gi.alaska.edu), Liguo Su, Dirk Lummerzheim, University of Alaska Fairbanks, Richard A. Doe, SRI International The energetics of the thermosphere can be investigated using laser spectroscopic methods to measure the vibrational and rotational states of molecular species in the thermosphere.

Energy Deposition in the Thermosphere A dual laser lidar system employing broad-band solid-state lasers could be used to profile two rotational states simultaneously and hence study the energy deposition in the auroral ionosphere.

Goals and Challenges Range-resolved measurement of vibrational and rotational states of thermospheric molecular species extends the scope of current radar/photometer experiments. Development of robust high-power laser technologies to support high-resolution measurements of species with small scattering cross-sections. Experimental and observational techniques (using lidar, radar and photometric instruments) need to be integrated and refined to yield robust measurements. Assimilation techniques will need to be developed to yield robust retrievals of ionospheric species.