华北2024年8月9日一次短时强降水的雷达特征

Radar Characteristics of a Short-Time Heavy Rainfall in North China on August 9, 2024

摘要: 本文利用DDW1三维全闪定位资料、双偏振雷达、地面降水及探空资料，选取2024年8月9日华北地区极端短时强降水过程，深入解析了强降水系统的动力–微物理–电活动三维演变特征。结果表明：本次极端降水过程中，强降水阶段对流核心反射率和KDP均处高值，ZDR柱顶高接近−20℃层，液态与过冷水被有效输送至混合相区0℃层以上重质冰相粒子(霰粒和冰雹)高度集聚并与强回波区重合，而轻质冰相粒子(冰晶、雪晶)则弥散分布于外围弱回波区。云闪辐射源主要分布在3~15 km高度，且分别有72.7%和50.9%的辐射源落入ZDR柱区和KDP高值区，展现出优异的空间匹配特征。充沛的过冷液态水、霰粒和冰晶在混合相态区的共存与碰撞，为非感应起电和云闪活动发展提供了有利的动力–微物理条件。

Abstract: In this paper, the extreme short-time heavy rainfall process in North China on August 9, 2024 is selected by using DDW1 three-dimensional all-flash positioning data, dual-polarization radar, surface precipitation and sounding data, and the three-dimensional evolution characteristics of dynamic-microphysical-electrical activity of heavy rainfall system are deeply analyzed. The results show that during this extreme precipitation process, the reflectivity and KDP of the convective core are high in the heavy precipitation stage, and the top height of the ZDR column is close to the −20˚C layer. The liquid and supercooled water are effectively transported to the mixed phase zone. Above the 0˚C layer, the heavy ice particles (graupels and hail) are highly concentrated and overlap with the strong echo area, while the light ice particles (ice crystals and snow crystals) are dispersed in the peripheral weak echo area. The cloud-to-cloud flash radiation sources are mainly distributed at the height of 3~15 km, and 72.7% and 50.9% of the radiation sources fall into the ZDR column area and the KDP high value area, respectively, showing excellent spatial matching characteristics. The coexistence and collision of abundant supercooled liquid water, graupel and ice crystals in the mixed phase region provide favorable dynamic-microphysical conditions for the development of non-inductive electrification and cloud flash activity.