The Differential Absorption LIDAR (DIAL) system is an airborne radar that measures water vapor, aerosols such as ozone, and clouds. DIAL flies aboard NASA’s DC-8 aircraft. The system uses five lasers to vertically profile ozone in ultraviolet light (UV) while simultaneously measuring water vapor in visible and infrared light. DIAL fires laser pulses upwards and downwards and a small fraction of the transmitted pulses are reflected from the atmosphere back to the aircraft and collected with a telescope receiver. The received light indicates the amount of water vapor along the path of the laser beam. Since DIAL’s creation, the system has been improved to provide aerosol backscatter, extinction, and depolarization profile measurements at three wavelengths (UV, visible, and near-infrared). The system also allows researchers to profile aerosol optical depth along the aircraft flight track.