高空槽背景下宝鸡太白一次强对流天气过程诊断分析

Diagnostic Analysis of a Strong Convective Weather Process in Baoji Taibai under the Background of High-Altitude Trough

摘要: 本文利用多源观测数据、探空资料及环流场数据，对2025年5月21~22日宝鸡太白强降水过程进行诊断分析，结果表明：此次过程是高空槽–中层切变–低空急流–地面低压多尺度系统协同作用的结果，500 hPa槽前正涡度区提供大尺度背景，700 hPa切变线触发扰动，850 hPa偏南风急流输送充足水汽与能量，地面低压倒槽增强辐合；水汽条件呈现干层→整层高湿→弱湿的演变，水汽通量散度的辐散–强辐合–弱辐合是降水阶段转变的核心驱动；热力上形成强对流不稳定层结，垂直速度的下沉→强整层上升→减弱直接驱动水汽垂直输送与能量释放。太白县因地形抬升叠加环流系统，出现以大雨为主、局地极端降水的空间分布特征。

Abstract: In this paper, the multi-source observation data, sounding data and circulation field data are used to diagnose and analyze the heavy precipitation process in Taibai, Baoji on May 21~22, 2025. The results show that the process is the result of the synergy of the multi-scale system of the high-altitude trough-middle shear-low jet-ground low pressure. The positive vorticity area in front of the 500 hPa trough provides a large-scale background, the shear line at 700 hPa triggers the disturbance, the southerly jet at 850 hPa transports sufficient water vapor and energy, and the ground low pressure inverted trough enhances convergence. The water vapor condition presents the evolution of dry layer-high humidity-weak humidity. The divergence-strong convergence-weak convergence of water vapor flux divergence is the core driving force of the precipitation stage transition. Thermally, a strong convective unstable stratification is formed, and the vertical velocity sinking-strong whole layer rising-weakening directly drives the vertical transport of water vapor and energy release. Due to the topographic uplift superimposed circulation system, Taibai County has the spatial distribution characteristics of heavy rain and local extreme precipitation.