西安“5·8”干旱背景下冰雹机理与服务响应

Mechanism and Service Response of Hail under Drought Background in Xi’an “5·8” Event

摘要: 2025年西安“5·8”冰雹发生于春季罕见干旱背景，且与全省抗旱人工增雨时空叠加，形成三重业务挑战。基于常规气象观测、雷达卫星观测、ERA5再分析及应急舆情多源数据分析，结果表明：(1) 此次冰雹是500 hPa高空槽冷平流与850 hPa西南暖湿急流交汇、地面冷锋触发，叠加适宜温层和垂直风切变的自然强对流结果；(2) 人工增雨仅补充凝结核，未改变强对流核心条件，与冰雹无直接因果关系；(3) 省级数值预报可捕捉强对流趋势，双偏振雷达可实现15~30分钟短临预警，预警精准性仍有提升空间；(4) 气象部门经应急响应、立体增雨和多平台科普，有效缓解旱情且快速消解负面舆情。综上，本研究可为北方干旱区应对同类复杂场景提供科学参考。

Abstract: The “5·8” hail event in Xi’an in 2025 occurred against the background of a rare spring drought and overlapped in time and space with the provincial-wide artificial precipitation enhancement operations for drought relief, resulting in triple operational challenges. Based on the analysis of multi-source data including conventional meteorological observations, radar and satellite observations, ERA5 reanalysis and emergency public opinion data, the results show that: (1) The hail was a natural severe convective outcome triggered by the conjunction of cold advection in the 500 hPa upper trough and the southwest warm and humid jet at 850 hPa as well as the surface cold front, superimposed with favorable temperature stratification and vertical wind shear; (2) Artificial precipitation enhancement only supplemented cloud condensation nuclei without changing the core meteorological conditions for severe convection, and had no direct causal relationship with the hail; (3) The provincial numerical forecast model could capture the overall trend of severe convection, and the dual-polarization radar could realize a 15~30 minute short-term early warning for hail, with room for improvement in early warning accuracy; (4) Through emergency response, three-dimensional artificial precipitation enhancement and multi-platform scientific popularization, the meteorological department effectively alleviated the drought and quickly eliminated negative public opinion. In summary, this study can provide a scientific reference for northern arid areas to respond to similar complex scenarios.