LIDAR PRINCIPLE Lidar physical principle is the same as for radar. A short pulse of laser light is transmitted from the telescope to the atmosphere. As the pulse travels along, part of it is scattered by molecules, anthropogenic particles, water droplets, or other objects in the atmosphere. The greater the number of scatterers, the greater the part scattered. A small portion of the scattered light is scattered back, collected by the telescope, and detected. The detected signal is stored for each probed length (bins) according to how long it has been traveled since the pulse was transmitted, which is directly related to how far away the backscatter occurred. The collection of bins for each pulse is called a profile. A bigger concentration in aerosol will be evident as an increase or spike in the back-scattered signal profile, since, for example, the water droplets that make up the cloud will produce a lot of backscatter.Read More »