乌鲁木齐机场一次雷暴大风过程诊断分析

Diagnosis and Analysis of a Thunderstorm Gale Process in Urumqi Airport

本文利用常规气象观测资料、探空资料、雷达资料、FNL 0.25˚ × 0.25˚再分析资料,诊断分析了2021年6月11日乌鲁木齐机场雷暴大风天气。结果表明:2021年6月11日发生在乌鲁木齐机场的雷暴大风天气过程为高空槽前波动型,巴尔喀什湖以北的高空槽缓慢东移,略有北收,新疆地区位于高空槽底前部,受西南气流控制,槽前多分裂短波并不断入侵新疆地区。低空辐合区和地形的强迫抬升作用,有利于不稳定能量的释放,造成本场雷暴天气。此次雷暴大风天气过程的水汽主要来源于巴尔喀什湖到北疆地区西南急流,且850 hPa有明显的风向风速辐合,造成水汽在乌鲁木齐机场西北侧有较强的辐合。强对流天气发生期间,有强辐合存在于对流层低层,中层为强辐散区,对应为强上升气流,高层为强辐合区,对应为强下沉气流,这是导致强对流发生发展的主要因素之一。

In this paper, utilizing conventional meteorological observation data, radiosonde data, radar data, and the FNL 0.25˚ × 0.25˚ reanalysis data, the thunderstorm gale weather at Urumqi Airport on June 11, 2021 was diagnosed and analyzed. The results show that the thunderstorm gale process that occurred at Urumqi Airport on June 11, 2021 was a type of pre-trough fluctuation, with the upper-level trough north of Lake Balkhash slowly moving eastward and slightly retracting northward. The Xinjiang region was located at the front part of the bottom of the upper trough, controlled by southwestern airflow. In front of the trough, the short wave split and invaded Xinjiang continuously. This condition was favorable for the release of unstable energy due to the low-level convergence zone and the forced lifting effect of the terrain, which caused the thunderstorm weather. The moisture for this thunderstorm high wind weather event primarily originates from the southwest jet stream from Lake Balkhash to the northwestern region of Xinjiang, with a noticeable convergence of wind direction and wind speed at 850 hPa, causing strong moisture convergence on the northwest side of Urumqi Airport. During the occurrence of the severe convective weather, strong convergence is present in the lower troposphere, with the mid-levels being a strong divergence zone corresponding to strong upward airflows, and the upper levels being a strong convergence zone corresponding to strong downward airflows. This is one of the main factors leading to the occurrence and development of severe convection.