Lidar/Laser Sounders
DIAL
The Differential Absorption LIDAR (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. The UV DIAL system uses five laser (or lidar) wavelengths in three different regions of the electromagnetic spectrum (Fig. 1): two in the UV region for ozone measurements, two in the visible region, and one in the near infrared (IR) region. IR and visible wavelengths both measure aerosols and clouds. Comparing these two wavelengths can reveal information about the size distribution of aerosols. The two UV wavelengths determine the profile of ozone by analyzing the absorption differences due to ozone between the two lidar returns. From this measurement, scientists can determine the location and amount of aerosols, clouds, and ozone along the line-of-sight of the UV DIAL system. Additional information available at "http://asd-www.larc.nasa.gov/lidar/lidar.html" [Summary provided by NASA}