Scanning tropospheric ozone and aerosol lidar with double-gated photomultipliers

The OzoneProfiling Atmospheric Lidaris a scanning four-wavelength ultraviolet differential absorption lidarthat measures tropospheric ozoneand aerosols. Derived profiles from the lidardata include ozoneconcentration, aerosolextinction, and calibrated aerosolbackscatter. Aerosolcalibrations assume a clear air region aloft. Other products include cloud baseheights, aerosollayer heights, and scans of particulate plumes from aircraft. The aerosoldata range from 280 m to 12 km with 5 m range resolution, while the ozonedata ranges from 280 m to about 1.2 km with 100 m resolution. In horizontally homogeneous atmospheres, data from multiple-elevation angles is combined to reduce the minimum altitude of the aerosoland ozoneprofiles to about 20 m. The lidardesign, the characterization of the photomultipliertubes, ozoneand aerosolanalysis techniques, and sample data are described. Also discussed is a double-gating technique to shorten the gated turn-on time of the photomultipliertubes, and thereby reduce the detection of background light and the outgoing laser pulse.