Temperature Results from the High-Power, Large-Aperture, Rayleigh-Scatter Lidar at Utah State University

Abstract:

The high-power, large-aperture, Rayleigh-Scatter Lidar at the Atmospheric Lidar Observatory at Utah State University (ALO-USU) has been significantly upgraded over the last few years. With almost 5 square meters of collecting area and 42 W of power at 532 nm, and a 30 Hz repetition rate, it has already probed the lower thermosphere up to 115 km. The intent is to reach 120 km on a regular basis. This much higher altitude limit for Rayleigh observations gives rise to challenges from changing neutral composition and for choosing an initial temperature. With one detector channel, the low-altitude limit is 70 km. The intent is to add a second detector channel to lower the low-altitude limit to 45 km. This will enable continuous observations of relative density and absolute temperature throughout the mesosphere and well into the lower thermosphere. This lower low-altitude limit also enables the new data to be combined with the existing 11-year, 45-to-90 km, mesospheric data set that began in 1993. By starting at 45 km, the Rayleigh lidar data can, furthermore, be combined with reanalysis models having upper altitude limits above 45 km, which will then give neutral densities and temperatures from 0 to 120 km.