An Observational Study of Low-Level Windshear at Hong Kong International Airport in Late Autumn and Early Winter

Case studies of low-level windshear and turbulence encountered by aircraft with actual pilot reports under all sky conditions are conducted for the first time at Hong Kong International Airport (HKIA) for late autumn to early winter (October to December of the year). These observational analyses follow from the recent enhancements of meteorological instrumentation at HKIA, namely, range–height indicator (RHI) scans of the light detection and ranging system (LIDAR) and the installation of Doppler microwave cloud radar in July 2025. Some novel features of windshear and turbulence are revealed in the present paper. In particular, windshear due to a low-level jet in the presence of liquid clouds shows up clearly in the cloud radar picture. The elevated and elongated mountain wake is well captured by the LIDAR’s RHI scans. And terrain-induced windshear is analyzed for light northerly wind conditions at HKIA. The combination of LIDAR and microwave cloud radar has the potential to provide a truly all-weather windshear and turbulence alerting service for aircraft. However, further research still needs to be performed, and this paper also discusses the future algorithm developments that would be required for this all-weather protection to be realized.