乌鲁木齐机场2021年2月一次冻雾、冻降水天气过程特征分析

Analysis on Weather Process Characteristics of Frozen Fog and Frozen Rain at Urumqi Airport in February 2021

本文通过对FNL (1˚ * 1˚)再分析资料、常规高空与地面资料、机场跑道自动观测系统(下文简称AWOS)、微波辐射计等资料的分析,探讨了乌鲁木齐机场2021年2月22日~23日一次冻雾、冻降水天气的时空分布、持续时间、气象层结等气象要素特征。研究结果表明:1) 此次冻雾、冻降水天气是受低涡底部偏西气流中的弱短波影响产生的;2) 此次冻降水天气低层水汽充沛,配合温度有丰富的过冷却水,受弱扰动影响,过冷却水凝结成过冷却水滴降落形成冻毛毛雨;3) 由于波动微弱,没有打破低层的稳定层结,同时前期降水使得低层增湿明显,有利于冻雾的出现和维持;4) 微波辐射计探测资料对大雾生消预报具有一定的指导意义。

This paper analyzes the data of FNL (1˚ * 1˚), conventional high altitude and ground data, airport runway automatic observation system (AWOS), Microwave radiometer etc., the temporal and spatial distribution, duration and stratification of frozen fog and frozen rain at Urumqi Airport 2021 from February 22 to 23. The results show that: 1) the frozen fog and frozen rain are influenced by the weak short wave in the westerly flow at the bottom of the vortex. 2) The frozen rain is full of water vapor in the lower layer, and there is abundant supercooled water in the lower layer with the weak disturbance. The supercooled water condenses into the supercooled water droplets and falls to form the freezing drizzle. 3) The weak fluctuation doesn’t break the stable layer of the lower layer. The early precipitation makes the lower layer wet obviously, which is beneficial to the occurrence and maintenance of frozen fog. 4) The Microwave radiometer data have certain guiding significance for the fog generation and dissipation prediction.