2024年2月西安机场一次罕见冻雨伴冰粒天气过程分析

Analysis of a Rare Freezing Rain Accompanied by Ice Particles Weather Process at Xi’an Airport in February 2024

摘要: 基于欧洲预报中心再分析资料、实况观测数据以及探空数据对西安机场一次罕见冻雨伴冰粒的天气过程进行了分析，结果表明：700 hPa低空急流和850 hPa的切变辐合为冻雨天气的发生提供了暖层、水汽和抬升条件；本次冻雨天气过程的形成机制为融化机制，“冷–暖–冷”的层结结构是冻雨产生的一个必要条件，且三个层次均需达到一定的厚度；“冷–暖–冷”的温度层结背景下，若中层暖层温度低于0℃，易出现阵性霰天气。

Abstract: Based on the reanalysis data from the European Forecasting Center, observational data, and radiosonde data, an analysis was conducted on a rare weather process of freezing rain accompanied by ice particles at Xi’an Airport. The results indicate that the low-level jet stream at 700 hPa and the shear convergence at 850 hPa provided the conditions of warm layer, water vapor, and lift for the occurrence of freezing rain. The formation mechanism of this freezing rain weather process is the melting mechanism, and the “cold-warm-cold” stratification structure is a necessary condition for the generation of freezing rain, with all three layers needing to reach a certain thickness. Under the “cold-warm-cold” temperature stratification background, if the temperature of the middle warm layer is below 0˚C, it is prone to occur with gusty sleet weather.