Hong Kong is implementing a Doppler LIght Detection And Ranging (LIDAR) System at the Hong Kong International Airport (HKIA) to supplement the Terminal Doppler Weather Radar (TDWR) in the detection and warning of low-level wind shear under clear-air conditions.

Installed in 1996, the TDWR has proved to be effective in the detection and warning of low-level wind shear in rainy weather. However, reports of wind shear received from aircraft pilots landing at or taking off from the new HKIA since its opening in 1998 indicated that low-level wind shear could also occur in clear-air conditions, under which TDWR return signals were not always available. Studies have shown that a majority of these low-level wind shear events were associated with airflow reaching the airport after passing over the hilly terrain of Lantau Island south of the airport. To handle such situations, a new means of detection not dependent on raindrops has to be found. The identified solution is a Doppler LIDAR operating at 2 micron wavelength which would give return signals from aerosols in clear air to allow Doppler wind measurements in fine weather.

This paper presents the overall plan of the LIDAR implementation in Hong Kong. Installation of the equipment is scheduled for 2002, to be followed by evaluation of its performance in the local environment. Important considerations like site selection, system characteristics, scan strategy and optimization of data update rates and coverage will be discussed. Similarities and differences between the LIDAR and TDWR in respect of low-level wind shear detection will be highlighted.