LIDAR-based Turbulence Intensity Calculation along Glide Paths

摘要

The use of glide-path scan data of the LIDAR at HKIA to calculate turbulence intensity distribution is presented in this paper. To minimize azimuthal averaging up to a range of 10 km for turbulence calculation, the laser beam is configured to scan at a rather slow speed of 0.8 degrees/s. As the LIDAR is required to perform other scans for operational applications, the slow scan and thus turbulence intensity calculation is only performed over the runway corridor to the west of the north runway, where most of the aircraft approaches are made. Two methods of determining turbulence intensity are considered, namely, the longitudinal and the azimuthal structure functions. They are found to provide comparable values of EDR~(1/3). The application of the turbulence intensity determined along the glide path is demonstrated using two examples of turbulence encounter by the pilots. The LIDAR-determined turbulence intensities are found to be generally consistent with the pilot reports. Future study would include the comparison of EDR~(1/3) values derived from the LIDAR and the flight data recorder (FDR) data of the aircraft. The methodology presented in this paper has the potential for application in turbulence alerting at the airport.