CEDAR-TIMED: Colorado State Sodium Lidar Update

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The investigators will upgrade the Colorado State narrowband sodium lidar from a one-beam system for measuring vertical profiles of temperature and sodium density to a two-beam system capable of simultaneously measuring heat flux, zonal and meridional winds, zonal momentum flux, and meridional momentum flux. The proposed upgrade doubles the power-aperture product of the lidar, making possible a two-beam operation with several operation geometries. The CSU lidar is now in its seventh year of operation and has provided unique observations in the mesopause region (80-105 km). The upgrade will allow better determination of the seasonal variations of mean temperature, winds, and tidal structure, and the evaluation of vertical gradients of heat flux and momentum flux. The mesopause is an important region of the atmosphere where gravity waves, depositing energy and momentum, force a diabatic mean meridional flow that is believed to be responsible for the cold summer and warm winter temperatures observed at those altitudes. These observations will support CEDAR/TIMED science goals. CEDAR, which stands for Coupling, Energetics, and Dynamics of Atmospheric Regions, is a global change program that combines theoretical modeling with ground-based measurements to study the upper atmosphere and ionosphere. TIMED, for Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics, is a NASA satellite program to study similar regions of the atmosphere. The joint CEDAR/TIMED program aims to coordinate ground-based and space-based observations to achieve better understanding of physical processes in the lower thermosphere and ionosphere.