激光测风雷达研究微下击暴流引发的低空风切变

较强的低空风切变会引发超低空复飞，对飞机安全威胁较大。为了提高飞行安全保障能力，利用激光测风雷达和风廓线雷达提供的资料，对2018-04-26西宁机场突发的一次风切变进行了细致结构分析和形成机理研究。结果表明, 微下击暴流是造成此次低空风切变的主要原因，雷暴高压向外辐散气流和环境风同向叠加是低空风切变形成的直接原因; 干冷空气在2.0km高度处加速下沉，到达近地面形成雷暴高压，随后外流形成水平尺度约3.0km的辐散气流，而触发低空风切变; 此次低空风切变影响时间约8min，对飞行安全威胁最大是下击暴流产生初期; 0.4km~2.0km高度处上升气流迅速转为下沉气流的时刻，较低空风切变发生有约4min的提前量。该研究对如何利用测风雷达进一步提高飞行安全保障能力是有意义的。

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.