Vertical profiles of temperature from NDACC/OHP Rayleigh Lidar Level 2

The Lidar is an instrument probing the atmosphere with a laser. By illuminating an atmosphere volume with a light pulsed, the backscattered light is collected with a telescope or lens and collected photons are detected with a photomultiplier using a counting mode when using a wavelength on the visible spectra domain. Differences in laser return times provide vertical information.The name lidar, is now used as an acronym of light detection and ranging. Rayleigh lidar uses the molecular scattering. In case the atmosphere is free of particles and remains with a constant mixing ratio, collected photons are linearly related to air density. In assuming air is in hydrostatic equilibrium and obeys the perfect gas law, the level 2 data will correspond to the Lidar Temperature Aerosols (LTA) profiles, which can be derived from 30 km to 80-90 km (Hauchecorne et al., 1980). The accuracy is better than 1K below 70 km. The design are described in Keckhut et al (1993).