乌鲁木齐机场一次雷暴外流引发风切变的成因分析

Analysis of the Causes of Wind Shear Induced by Thunderstorm Outflow at Ürümqi Airport

摘要: 为提高对雷暴外流引发风切变的认知并提升机场预警预报能力，本文利用FNL 0.25˚ × 0.25˚再分析资料、机场自动观测资料、多普勒雷达资料及激光测风雷达资料，对2023年6月21日夜间乌鲁木齐国际机场发生的雷暴外流风切变过程展开系统分析。结果表明：(1) 此次过程受巴湖暖脊脊前西北气流输送冷空气、地面切变线辐合共同驱动，“下层暖湿、上层干冷”的垂直温湿廓线与低空辐合–高空辐散配置提供了有利对流环境；(2) 多普勒雷达监测到多单体风暴相互作用激发大风东移，激光测风雷达捕捉到 200~500米高度20 m/s大风核及低空急流下压过程，下滑道风场风向快速转换(偏北–西北–西南)与0.14/s侧风切变指数是航空器中止进近、复飞的直接原因。

Abstract: To enhance the understanding of wind shear induced by thunderstorm outflows and improve the airport’s early warning and forecasting capabilities, this study conducts a systematic analysis of the thunderstorm outflow-induced wind shear event that occurred at Urumqi International Airport on the night of June 21, 2023. The analysis utilizes FNL 0.25˚ × 0.25˚ reanalysis data, airport automatic observation data, Doppler radar data, and lidar wind profiler data. The results show that: (1) This event was jointly driven by the cold air transport from the northwest airflow ahead of the Balkhash Lake warm ridge and the convergence of the surface shear line. The vertical temperature and humidity profile characterized by “warm and moist air in the lower layer and dry and cold air in the upper layer”, combined with the configuration of low-level convergence and upper-level divergence, provided a favorable convective environment. (2) Doppler radar detected that the interaction of multi-cell storms triggered the eastward movement of strong winds. The lidar wind profiler captured a strong wind core with a speed of 20 m/s at an altitude of 200~500 meters and the downward propagation process of the low-level jet. The rapid wind direction change (from northerly to northwesterly to southwesterly) in the glide path wind field and the crosswind shear index of 0.14/s were the direct causes for aircraft to abort approach and go around.