A Vaisala CL61 depolarisation lidar continually measures cloud height, cloud droplets, aerosol load, ice particles, and precipitation at GFI weather garden. Attenuated backscatter and depolarisation are acquired every 1 min.

A laser pulse is emitted from the ground up to 10km, and scattered by atmospheric particles. One can derive cloud height and type, as well as aerosol load from the intensity of the backscatter, and the depolarisation of the returned laser signal. The depolarisation scale provides insight into the type of particles.