衡阳暖区暴雨的天气分型和回波特征分析

Analysis on the Classification and Echo Feature of Warm-Sector Rainstorm in Hengyang

摘要: 利用常规地面资料、逐小时自动站降水资料、探空站资料、NCEP/NCAR再分析资料及多普勒雷达资料等对衡阳市2008~2020年的暖区暴雨过程进行收集筛选、统计分析等。研究发现：2008~2020年衡阳市共计发生12次暖区暴雨过程，全部为切变型，包含冷切变型9例及暖切变型3例，主要影响系统有500 hPa高空低槽、低空急流及地面辐合线；衡阳暖区暴雨对流性质明显且降水集中在夜晚，全部发生在4~6月；具有较大的CAPE (>400 J/kg)及K指数(>36 K)，而CIN (小于50 J/kg)较小，0℃层高度在4800至5500 m之间；衡阳暖区暴雨的雷达回波特征有后侧反射率因子梯度增大、后侧入流缺口、弓形回波、速度辐合、大风区、垂直风切大等。

Abstract: Using the conventional meteorological observation data, the NCEP 1˚ × 1˚ reanalysis data from 2008 to 2020, hourly automatic station precipitation data, radiosonde station data and Doppler radar data collected, filtrated and statistically analyzed the process of warm-sector rainstorms in Heng-yang City from 2008 to 2020. The study found that: in Hengyang City, all told there were 12 warm-sector rainstorms from 2008 to 2020, all for shearline type, including 9 cold shearline type cases and 3 warm shearline type cases. The main impact systems are 500 hPa high altitude trough, low-level jet and surface convergence line. The warm-sector rainstorms in Hengyang are obvious convective and concentrated at night, all of which occur in April to June. They have large CAPE (>400 J/kg) and K index (>36 K), while CIN (less than 50 J/kg) is small, and the height of 0˚C layer is between 4800 and 5500 m. The radar echo characteristics of rainstorm in Hengyang warm-sector including the increase of rear reflectance factor gradient, rear inlet notch, bow echo, velocity convergence, strong wind area, large vertical wind cut and so on.