Lidar measurements of the optical propagation environment

Results of lidar measurements are reported, particularly the layering of tropospheric haze and extinction/backscatter by cirrus clouds at visible wavelengths. This work includes the operation of a fixed lidar at College Park, and a transportable lidar for geographic locations of interest to DoD. A sensitivity baseline for these lidars was established using Rayleigh backscatter from the altitude molecular atmosphere. Profiles of temperature and density cover the altitude range 30 to 80 km. For cirrus clouds, measured relationships between extinction and backscatter make it possible to estimate the long-range horizontal visibility through cirrus layers via calibrated backscatter observations. Inversion of tropospheric haze measurements to vertical profiles of extinction is reported. Applicability of lidar probe methods to energy and information transfer through the atmosphere is summarized. Upper atmosphere observations are discussed, relevant to the prediction of atmospheric effects on reentry vehicles.