AIRBORNE CO2 COHERENT LIDAR FOR MEASUREMENTS OF ATMOSPHERIC AEROSOL AND CLOUD BACKSCATTER

An airborne CO2 coherent lidar has been developed and flown on over 30 flights of the NASA DC-8 research aircraft to obtain aerosol and clou d backscatter and extinction data at a wavelength near 9 mum. Designed to operate in either zenith- or nadir-directed modes, the lidar can b e used to measure vertical profiles of backscatter throughout the vert ical extent of the troposphere and the lower stratosphere. Backscatter measurements in absolute units are obtained through a hard-target cal ibration methodology. The use of coherent detection results in high se nsitivity and narrow field of view, the latter property greatly reduci ng multiple-scattering effects. Aerosol backscatter profile intercompa risons with other airborne and ground-based CO2 lidars were conducted during instrument checkout flights over the NASA Ames Research Center before extended deployment over the Pacific Ocean. Selected results fr om data taken during the flights over the Pacific Ocean are presented, emphasizing intercomparisons with backscatter profile data obtained a t 1.06 mum with a NASA Goddard Space Flight Center Nd:YAG lidar on the same flights.