Aerosol Backscatter Coefficient Profiles Measured at 10.6μm

Abstract

Using an airborne lidar, we have measured atmospheric aerosol backscatter coefficients (differential backscatter cross section per unit volume) for 10.6 μm wavelength laser radiation as a function of height to 5200 m for a number of meteorological conditions over the United States high plains. Airborne in situ samplers measured the particle size distribution at the same time and altitude as the lidar measured backscatter. One backscatter coefficient profile at 10.6 μm was compared with a 0.694 μm lidar backscatter profile as well as with the particle size distribution profile. The average infrared backscatter coefficient ranged from ∼8 × 10⁻⁹ m⁻¹ sr⁻¹ at the surface to 1 × 10⁻¹⁰ sr⁻¹ at 5200 m altitude.