Rayleigh/Raman Temperature Technique and Design

The Rayleigh temperature lidar technique uses the backscattering properties of the air molecules, and the hydrostatic and ideal gas properties of the atmosphere. In the absence of particles such as aerosols and clouds (typically above 30 km), the number of photons collected on the lidar receiver is proportional to the number of backscattering air molecules. After various corrections and normalization to a concurrent pressure or density profile, the lidar number density profile is integrated downward from the top of the profile, allowing, for typical existing Rayleigh lidars, the retrieval of atmospheric temperature between 30 and 80 km. A similar method, applied to the lidar signals returned from vibrational Raman scattering by atmospheric Nitrogen (insensitive to particles), allows to extend temperature retrieval downward to about 10 km. Rayleigh/Raman temperature lidar systems typically have a temperature error ranging from less than 0.5 K in the mid-stratosphere to 15 K in the upper mesosphere (limited by signal-to-noise ratio and initialization).

There are fourteen Rayleigh temperature lidar systems included in NDACC. Twelve systems are at fixed locations, two systems are mobile. The twelve fixed systems are located at Observatoire de Haute-Provence (France), Hohenpeissenberg (Germany), Payerne (Switzerland), Table Mountain Facility (California), Mauna Loa Observatory (Hawaii), Ny-Alesund (Spitzbergen), Andoya (Norway), Reunion Island (Indian Ocean), London (Canada), Eureka (Canada), Sondrestromfjord and Thule (both in Greenland). The two mobile systems are home based at the NASA Goddard Space Flight Center in Greenbelt, Maryland (USA).

Back to Top