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Urban aerosol spatial variations using a slant-angle scanning Mie lidar system

An eye-safe, mobile micro-pulse Mie Lidar system has recently been integrated. The system is capable of taking slant angle 360 degree horizontal scans of aerosol distributions, as well as vertical boundary-layer profiles in a zenith pointing position. The Lidar is co-axial, and the transmitter is a high repetition rate, diode-pumped micro-joule pulse energy, Nd:YAG 532 nm laser. The receiver is a compact Schmidt-Cassegrain f/6.3 telescope. The whole system can be fitted into a small van for field observations. The main objective in building this Lidar in Hong Kong is for monitoring spatially varying aerosols and vertical distributions within the lower few km of the troposphere. In this paper, the near range corrections from geometric ray tracing are presented together with field data. Representative spatial scans over urban Hong Kong are also given. The new system will be deployed in the very near future to study the correlation between the spatial distribution of aerosols and local traffic conditions. The Lidar design may represent a typical commercial product of the current technology.