The ozone hole, the greenhouse effect, and global warming are concerns at the center of people's interest about the atmosphere. A lidar is an instrument that uses short pulses of laser light to detect particles or gases in the atmosphere much like radar bounces radio waves off rain in clouds. A telescope collects and measures reflected laser radiation, leading to a map of the atmosphere's structure. Researchers can then determine the location, distribution, and nature of atmospheric particles and clouds and, under special circumstances, molecular species. Different types of lidars measure different atmospheric properties.
Scientists know that different molecules absorb light only at certain wavelengths.
They can then tune laser pulses to different wavelengths to target the type of atmospheric gases they want to study. The NASA Langley airborne UV DIAL system is a lidar instrument that sends pulses of laser radiation at different wavelengths into the atmosphere to measure ozone and also simultaneously measure aerosols and clouds. The laser beams are pointed both upwards and downwards out of the aircraft. IR and visible wavelengths both measure aerosols and clouds. Comparing these two wavelengths can reveal information about the size distribution of aerosols.