Case study of a special event of low-level windshear and turbulence at the Hong Kong International Airport

A case study of a special event of low-level windshear and turbulence at the Hong Kong International Airport is performed. The mountainous Lantau Island to the south of the Airport may lead to terrain-disrupted airflow disturbances in the Airport area in certain wind directions, resulting in low-level windshear and turbulence to the aircraft. There are a number of novel features in the flow field in the airport region. First, over the seas to the west of the airport, there is sharp convergence between northerly flow and southerly flow within a short distance. Second, in the temperature measurements over this region, there are sharp increases and decreases in temperature. The performance of a high-resolution numerical weather prediction model in predicting these features is studied. It is shown that, though the model is quite successful in reproducing some features, it may not be able to capture some novel features, such as a sharp rise of temperature and sharp convergence of the airflow. The case study may be a useful reference for aviation weather forecasters and mountain meteorologists.