A four dimensional variational (4DVAR) data analysis method is developed to analyze the Doppler LIDAR data collected at the Hong Kong International Airport (HKIA). Two cases of terrain-disrupted airflow at HKIA are analyzed. These include the occurrence of mountain wave and the hydraulic-jump-like feature of the airflow downstream of a valley in the airport area. Though only the radial velocity data from three conical scans at low elevation angles (0-degree, 1-degree and 4.5-degree from the horizon) are employed, the 4DVAR analysis results turn out to successfully capture the mountain wave and jump-like airflow within the boundary layer of the atmosphere. This paper presents the formulation of the 4DVAR method and the analysis results of the two cases of terrain-disrupted flow.