2026年1月下旬湖北低温雨雪冰冻天气过程区域特征对比分析

Regional Comparative Analysis of a Low-Temperature Rain-Snow-Freezing Process in Hubei in Late January 2026

摘要: 受强冷空气和西南暖湿气流共同影响，2026年1月下旬湖北自北向南出现大范围低温雨雪冰冻天气，鄂西北和鄂东南在相态转换和积雪深度方面存在明显差异。利用湖北天擎实况观测资料、欧洲中期数值预报中心(ERA5)再分析资料以及探空资料，对比分析两个区域在温度层结、水汽及微物理和动力等方面基本特征差异，得出以下结论：(1) 鄂西北地区降温早，冷垫厚，降雪持续时间长；鄂东南经历了由雨转雪的相态变化且降雪持续时间相对较短。(2) 逆温强度与降水相态关系密切，在白天鄂西北降雪时的逆温强度大于鄂东南降雨时的逆温强度，到夜间鄂东南由雨转雪后，逆温强度增强并且超过鄂西北。(3) 鄂西北与鄂东南降水较强时段均有明显的水汽通量辐合，水汽通量中心高度随着雨转雪的相态转换逐渐抬高。(4) 鄂西北湿层伸展高，云冰含量多，以干雪为主；鄂东南云水含量多，雨转雪时湿层伸展高度增高，云冰含量相对增大，以湿雪为主。

Abstract: Under the combined influence of strong cold air and warm, moist southwesterly airflow, a widespread low-temperature rain, snow and freezing weather event affected Hubei from north to south in late January 2026. Significant differences in phase transition and snow depth were observed between northwestern Hubei and southeastern Hubei. Using observational data from Hubei Tianqing, ERA5 reanalysis data, and sounding data, this study comparatively analyzes the basic characteristic differences in temperature stratification, moisture and microphysics, dynamic conditions, and instability. The main conclusions are as follows: (1) In northwestern Hubei, temperatures dropped earlier, the cold layer was thicker, and snowfall lasted longer; southeastern Hubei experienced a rain-to-snow transition with a relatively shorter snowfall duration. (2) The intensity of the temperature inversion was closely related to the precipitation phase. During the daytime, the inversion intensity during snowfall in northwestern Hubei was greater than that during rainfall in southeastern Hubei. At night, after the rain turned to snow in southeastern Hubei, the inversion intensity strengthened and exceeded that in northwestern Hubei. (3) During the periods of stronger precipitation, both northwestern and southeastern Hubei exhibited significant water vapor flux convergence, and the height of the water vapor flux center gradually increased with the rain-to-snow transition. (4) In northwestern Hubei, the moist layer extended higher, cloud ice content was higher, and dry snow was dominant; in southeastern Hubei, cloud water content was higher, and during the rain-to-snow transition, the moist layer extended higher while cloud ice content increased relatively, with wet snow being dominant.