邵阳2024年两次低温雨雪天气过程对比分析

Comparative Analysis of Two Low-Temperature Rainy and Snowy Weather Processes in Shaoyang in 2024

摘要: 2024年2月初，受持续性冷空气影响，湖南邵阳地区出现了较为罕见的持续性低温雨雪冰冻天气，邵阳市区和邵东48 h最低气温降幅达7.5℃以上，2月2日至7日全市平均气温0.9℃，较历年同期(6.5℃)偏低5.9℃。对EC模式预报产品检验分析发现，最新起报时次的各层温度0线、逐3小时和逐6小时降雪量，对预报雨雪相态转换以及降雪落区具有很好的指示作用。在本轮过程中700 hPa 0℃线南压至邵阳是降水相态转为雪的重要经验指标，降水相态为冻雨时的850 hPa温度和地面温度低于雨夹雪。双偏振雷达CC、ZDR与KDP产品在本次低温雨雪过程中对降水相态的判定有较为明显的指示作用。

Abstract: In early February 2024, due to the continuous cold air, Shaoyang area in Hunan Province experienced a rare sustained low-temperature rain, snow, and freezing weather. The minimum temperature in Shaoyang city and Shaodong decreased by more than 7.5˚C in 48 hours. From February 2nd to 7th, the city’s average temperature was 0.9˚C, which was 5.9˚C lower than the same period in previous years (6.5˚C). The inspection and analysis of EC model forecast products found that the zero temperature line at each layer and the snowfall amount every 3 hours and 6 hours at the latest evening are good forecast indexes for forecasting the phase of rain and snow and the transformation of snowfall regions. In this round, the southward pressure of the 700 hPa 0˚C line to Shaoyang is an important empirical indicator for the transition of precipitation phase to snow. When the precipitation phase is freezing rain, the 850 hPa temperature and ground temperature are lower than those of sleet. The products of dual-polarization radar CC, ZDR and KDP have obvious indication function on the judgment of precipitation phase in the process of low temperature rain and snow weather.