Airborne scanning lidar observations of aircraft contrails and cirrus clouds during SUCCESS

Abstract

An angular scanning backscatter lidar was deployed on the NASA DC-8 research aircraft as part of SUCCESS. The lidar viewing direction could be continuously scanned from vertically upward to forward to vertically downward. Real-time pictorial displays generated from lidar signatures were used to locate clouds and contrails above, ahead of, and below the DC-8; to depict their spatial structure; and to help select DC-8 altitudes for achieving optimum sampling by onboard in situ sensors. The lidar data are being analyzed to establish their value in the interpretation and extension of the in situ sensor databases. Data examples are presented that illustrate 1) correlation with particulate, gas, and radiometric measurements made by onboard sensors, 2) discrimination and identification between contrails observed by the onboard sensors, 3) a 13.1 km altitude layer that exhibits greatly enhanced vertical backscatter relative to off-vertical backscatter, and 4) mapping of vertical distributions of individual precipitating ice crystals and their capture by cloud layers.