Multi-wavelength lidar Lidar1200. A Raman water vapor lidar emitting at 355 nm has been operating at the Maïdo Observatory since April 2013 (Baray et al., 2013; Keckhut et al., 2015; Vérèmes et al., 2019). Laser pulses are generated by two Quanta Ray Nd:Yag lasers, the geometry for transmitter and receiver is coaxial and the backscattered signal is collected by a Newtonian telescope with a primary mirror of 1200 mm diameter. 387 nm (N 2 ) and 407 nm (H 2 O) Raman shifted wavelengths are used to retrieve the water vapor mixing ratio.