2022年长沙一次低温雨雪冰冻天气成因及预报偏差分析
Analysis on the Cause and Forecast Deviation of a Low-Temperature Freezing Rain and Snow Disaster in Changsha in 2022

利用高空和地面观测资料、数值模式资料以及雷达资料，分析了长沙地区2022年2月6~9日低温雨雪冰冻天气过程的成因及预报偏差，得出以下结论：1) 整个降雪过程分为两个阶段，雨雪区域均自西向东逐步推进。2) 第一阶段表现为低槽东移型，东移过程中不断引导冷空气南下；第二阶段表现为小槽发展型，受强冷平流影响小槽发展。3) 两个降雪阶段中，低空急流都是水汽条件主要提供者，并且整层温度低于0℃是雨雪相态转换的关键。
Using high-altitude and ground observation data, numerical model data and radar data, formation cause and forecast deviation of a low-temperature freezing rain and snow disaster in Changsha from February 6 to 9, 2022 were analyzed. The results showed that: 1) the whole snowfall process was divided into two stages. Rain/snow areas were gradually advancing from west to east. 2) The first stage is that the low trough moves to the east and continuously guides the cold air southward in the process while the cond stage is that strong cold advection leads to the low trough developing. 3) The low-level jet provides good water vapor conditions for the two stages and the temperature below 0？C was the key factor for precipitation phase.