乌鲁木齐机场2021年6月11日雷雨大风天气特征分析

Analysis of Thunderstorm and Gale Weather Characteristics at Urumqi Airport on June 11, 2021

摘要: 本文利用机场自动气象观测系统观测资料、乌鲁木齐机场航空器空中报告及ERA5再分析资料对2021年6月11日的雷雨大风天气进行诊断分析，了解雷雨大风天气形势特征及此类天气条件下风切变的变化特点及其对飞行的影响，以期提高此类对此类天气的预报预警能力。结果表明：(1) 此次雷雨大风天气为区域性强对流天气。500 hPa高空槽槽底不断分裂小股冷空气影响新疆地区，区域雷雨天气提供有利触发机制；700 hpa西南气流输送暖湿气流进入北疆区域，提供热力和水汽条件；850 hpa北疆沿天山一带受西北风带控制，明显的风向风速辐合配合天山北坡地形的强迫抬升作用，造成强上升运动，提供了动力条件。前期北疆大部区域地面气温高，冷空气东移造成冷暖空气交汇，造成此次强对流天气。(2) 雷雨天气初期冷空气进入本场，跑道两端风速骤增，风向变化大时易产生跑道两端水平风切变超标准，虽然风切变超标情况持续时间较短，但仍会造成航空器起降过程中难以保持飞行姿态，严重影响航空器飞行安全。(3) 跑道两端风速差及风向差较小时，不易产生风切变超标；跑道两端风速差大于6 m/s时，无论风向差值大小，均可能出现风切变超标。跑道两端风向差在30˚~90˚之间时，风速差异对风切变的影响权重逐步增大；两端风向差大于90˚时，不论风速差大小，均有可能出现风切变超标情况。

Abstract: This article diagnoses and analyzes the thunderstorm and strong wind weather on June 11, 2021, using observation data from the airport’s automatic meteorological observation system, aerial reports from aircraft at Urumqi Airport, and ERA5 reanalysis data. It aims to understand the characteristics of thunderstorm and strong wind weather forms and the changes in wind shear under such weather conditions, as well as their impact on flight, in order to improve the forecasting and early warning capabilities of such weather. The results indicate that: (1) This thunderstorm and strong wind weather is a regional strong convective weather. The continuous splitting of small cold air streams at the bottom of the 500 hPa high-altitude trough affects the Xinjiang region, providing a favorable triggering mechanism for regional thunderstorm weather; The southwest airflow at 700 hpa transports warm and humid air into the northern Xinjiang region, providing thermal and water vapor conditions; The area along the Tianshan Mountains in northern Xinjiang at 850 hpa is controlled by the northwest wind belt, and the obvious convergence of wind direction and speed, combined with the forced uplift effect of the northern slope terrain of the Tianshan Mountains, causes strong upward movement and provides dynamic conditions. In the early stage, the surface temperature in most areas of northern Xinjiang was high, and the eastward movement of cold air caused the convergence of cold and warm air, resulting in this severe convective weather. (2) In the early stages of thunderstorm weather, cold air enters this area, causing a sudden increase in wind speed at both ends of the runway. When the wind direction changes greatly, it is easy to produce horizontal wind shear exceeding the standard at both ends of the runway. Although the duration of wind shear exceeding the standard is relatively short, it still makes it difficult for the aircraft to maintain its flight attitude during takeoff and landing, seriously affecting the safety of aircraft flight. (3) When the difference in wind speed and direction between the two ends of the runway is small, it is not easy to generate excessive wind shear; When the wind speed difference between the two ends of the runway is greater than 6m/s, regardless of the magnitude of the wind direction difference, excessive wind shear may occur. When the wind direction difference between the two ends of the runway is between 30˚~90˚, the weight of the impact of wind speed difference on wind shear gradually increases; When the wind direction difference between the two ends is greater than 90˚, regard-less of the size of the wind speed difference, there is a possibility of excessive wind shear.