乌鲁木齐机场一次由对流天气引起的低空风切变特征分析

Analysis of Low-Level Wind Shear Characteristics Caused by Convective Weather in Urumqi Airport

摘要: 利用NCAR/NCEP FNL 1˚ × 1˚再分析资料和机场自动观测系统(AWOS)风数据对2019年7月18日发生在乌鲁木齐机场的一次对流型低空风切变进行分析。结果发现，此次对流型低空风切变是在弱天气尺度强迫下由短波槽和切变线触发不稳定能量所致。对流单体移动过程中产生的阵风是造成此次低空风切变的主要原因，因此低空风切变的变化与阵风的变化有很好的对应。低空风切变具有明显的阵性特征，持续时间波动较大，最短1分钟，最长13分钟；当跑道两端风向差足够大时，即使风速差小于2 m/s也能达到告警标准。

Abstract: The characteristics of low-level wind shear that occurred on July 18, 2019 at Urumqi Airport are analyzed on the basis of NCAR/NCEP FNL 1˚ × 1˚ reanalysis data and the real-time wind data from airport runways automatic observation system (AWOS). The results show that the convective low- level wind shear was caused by unstable energy triggered by short wave troughs and wind shear lines under weak weather scale forcing. The gust generated by the movement of convective cells is the main cause of the low-level wind shear, so the change of low-level wind shear corresponds well with the change of gust. The low-level wind shear has obvious gusty characteristics, with significant fluctuations in duration, ranging from 1 minute to 13 minutes, when the wind direction difference between the two ends of the runway is large enough, even if the wind speed difference is less than 2 m/s, the alarm is still met.