Observation and numerical simulation of terrain-induced windshear based on RHI scans of the Doppler LIDAR

Terrain-induced windshear is a major source of hazardous weather for the Hong Kong International Airport. Windshear is mostly detected by conical scans of Doppler LIDARs in Hong Kong. RHI scans have been stopped for long time and there are only limited observations. This study is the first of its kind for Hong Kong to use RHI scans of a Doppler LIDAR to capture the windshear features, including some tropical cyclone cases. The RHI scans show some interesting features such as mountain waves, vortices and high speed streaks which may be related to the reported windshear from the pilots. High resolution numerical simulation of such features have also been performed using regional atmospheric modelling system (RAMS). With proper turbulence parameterization schemes, some windshear features could be reproduced successfully. This presentation would be useful for aviation weather forecasters in other airports with similar windshear featurs.