拉萨贡嘎机场“雷阵雪”强对流天气多模式融合过程分析与预报优化

Analysis and Forecast Optimization of Multi Model Fusion Process for Severe Convective Weather of “Thunderstorm Snow” at Lhasa Konggar Airport

摘要: 2025年4月28日夜间至29日凌晨，拉萨贡嘎机场遭遇罕见的“雷阵雪”强对流天气，过程累计降水量达26 mm，最大小时雨强9.6 mm，伴随强雷电、小冰雹、阵雪及偏北阵风，多架航班受天气影响返航备降。本文基于多源观测资料、再分析场及ECMWF/GFS等数值模式，系统复盘此次高高原机场强对流过程，评估多模式预报性能，分析“雷阵雪”形成机制，并提出多模式融合优化方案。研究表明：高原低涡切变在“两槽一脊”环流和双高压挤压下稳定维持，西南暖湿气流与偏北强冷空气剧烈对冲触发强对流；高层充沛过冷水汽导致冰相过程主导，是“雷阵雪”关键成因；多模式对高高原机场环流形势预报准确但存在降水低估和时序偏差情况，需结合实况观测动态订正。此外，高高原机场在各项指数预报上，与内地机场也有很大不同。本文旨在通过过程分析，总结高高原机场冰相对流过程，为高高原机场春夏及秋冬换季期间此类预报提供借鉴。

Abstract: On the night of April 28th to the early morning of April 29th, 2025, Lhasa Konggar Airport experienced a rare “thunderstorm snow” severe convective weather, with a cumulative precipitation of 26 mm and a maximum hourly rainfall of 9.6 mm. Along with strong lightning, small hail, snow showers, and northerly gusts, multiple flights were affected by the weather and returned to alternate airports. This article is based on multi-source observation data, reanalysis fields, and numerical models such as ECMWF/GFS. It systematically reviews the strong convective process at the high-altitude airport, evaluates the performance of multimodal forecasting, analyzes the formation mechanism of “thunderstorms snow”, and proposes a multimodal fusion optimization scheme. Research has shown that the shear of the plateau vortex is stably maintained under the “two troughs and one ridge” circulation and double high pressure compression, and strong convection is triggered by the intense opposition between the southwest warm and humid airflow and the northerly strong cold air; The abundant supercooled water vapor in the upper floors leads to the dominance of ice phase processes, which is the key cause of “thunderstorms snow”; Multimodal forecasting of circulation patterns in high-altitude airports is accurate, but there are underestimations of precipitation and temporal deviations, which need to be dynamically corrected in conjunction with actual observations. In addition, high-altitude airports have significant differences in various index forecasts compared to mainland airports. This article aims to summarize the process of ice convection in high-altitude airports through process analysis, and provide a reference for such forecasts during the spring summer and autumn winter seasons of high-altitude airports.