Identification and analysis of terrain-induced low-level windshear at Hong Kong International Airport based on WRF-LES combining method

Terrain-induced low-level windshear is characterized by high variability and small spatiotemporal scales. It seriously threatens the safety of aircrafts and reduces the operational efficiency of airports. The objective of the study was to identify terrain-induced low-level windshear over the airport area. A large-eddy simulation (LES) based on the data from WRF (weather research and forecasting) model was used to design a high-resolution WRF-LES simulation method. This method was applied to simulate a typical case of windshear at Hong Kong International Airport (HKIA) on 5 March 2015. The model results were compared with anemometer measurements and LiDAR scanning data of HKIA, which was found to capture many intra-airport wind features and microscale flows. The F-factor was employed to quantitatively describe the probability and range of windshear. This study demonstrates that the WRF-LES system is a valuable tool for simulating real-world microscale weather flows, which could be useful for the development of the real-time windshear forecasting system. Although further LES model refinements are highly desired, it presents a new idea for studying the characteristics of flow field with unsteady boundary conditions.