A study on low-level wind shear caused by microburst using lidar and other data

A strong low-level wind shear can cause a super low-level go around, which is a great threat to aircraft safety. In order to improve the ability of safeguard flight safety, the detailed structure and genesis mechanism of the wind shear event were studied using lidar, wind profile radar and other data of Xining Airport on 2018-04-26. The results indicate that microburst is the main cause of the low-level wind shear. The direct reason for the formation of low-level wind shear is the thunderstorm high divergent airflow and the ambient wind which is superposed in the same direction. The dry cold air subsided quickly from an altitude of 2.0km to the near ground and formed a thunderstorm high pressure, and then became an outflow that formed a divergent flow at a horizontal scale of about 3.0km, triggering low-level wind shear. This low-level wind shear lasted about 8min, of which poses the greatest threat to flight safety is at the initial generation of downburst. The time for updraft quickly turning to downdraft at 0.4km~2.0km height is about 4min ahead of the occurrence of low-level wind shear. The research is significant to use wind lidar to improve the ability of flight safety support.