Key Laboratory for Semi-Arid Climate Change of the Ministry of Education;
College of Atmospheric Sciences;
Lanzhou University;
Lanzhou 730000;
Gansu Sub-Bureau of Northwest Air Traffic Management Bureau of Civil Aviation of China;
Lanzhou 730087;
Hong Kong Observatory;
Kowloon;
Hong Kong 999077;
low-level wind shear; synoptic situations; alerting algorithm; Doppler lidar;