2024年6~7月湘中邵阳持续性强降水雷达回波特征分析

Radar and Satellite Characteristics of Persistent Heavy Precipitation in Central Hunan (Shaoyang) from Late June to Early July 2024

摘要: 2024年6月16日至7月2日，湘中邵阳出现一次持续性极端强降雨天气过程，具有雨强大、极端性突出、暴雨落区高度重叠、致灾严重等特点。本文综合利用FY-2G卫星TBB、S波段双偏振雷达及区域自动站观测资料等，重点剖析了降水最强时段的对流云团演变与雷达回波结构。结果表明：本次过程中小时雨强 ≥ 80 mm时，对流云团TBB低于−72℃；对流系统后向传播与列车效应共同作用，叠加地形增幅和前期降水水汽累积效应，是本次暴雨持续时间长、落区高度重叠的关键原因；雷达双偏振参量ZDR、KDP大值区与强降水落区高度吻合，其中KDP的突变特征能够精准定位极端降水核心区域。研究结论可为湘中地区夏季持续性极端暴雨的机理研究、监测预警工作提供参考。

Abstract: From June 16 to July 2, 2024, a persistent extreme heavy rainfall event occurred in Shaoyang, central Hunan Province, characterized by high hourly intensity, remarkable extremity, highly overlapping rainstorm locations, and severe societal impacts. Using FY-2G satellite black-body brightness temperature (TBB), S-band dual-polarization radar, and regional automatic weather station observations, this study examined the evolution of convective cloud clusters and radar echo structures during the most intense precipitation period. The results show that: (1) when the hourly rainfall intensity reached ≥80 mm, the TBB of convective cloud clusters was consistently lower than −72˚C; (2) the combined action of backward propagation and the train effect, together with terrain amplification and moisture accumulation from antecedent precipitation, was the key reason for the long duration of the rainstorm and the high overlap of rainstorm locations; (3) the high-value zones of the dual-polarization parameters ZDR and KDP were highly consistent with heavy-rainfall areas, and the abrupt variation of KDP could accurately pinpoint the core regions of extreme precipitation. These conclusions provide a reference for mechanism research and monitoring-early-warning practices of persistent extreme summer rainstorms in central Hunan.