The brilliant green beam of the lidar at the Mauna Loa Observatory (MLO) measures aerosols and water vapor high in the stratosphere. This unretouched image was made when fog briefly formed during an observing session. The camera was leaned against the side of the dome that houses the Dobson spectroradiometer that measures the ozone layer. Mauna Loa, Hawaii, June 25, 2001. LIDAR (Light Detection And Ranging, also LADAR) is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser. LIDAR technology has application in geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, remote sensing and atmospheric physics, as well as in airborne laser swath mapping (ALSM), laser altimetry and LIDAR contour mapping.