Abstract To conduct accurate lightning prediction and nowcasting, it is important to clarify the relationship between electrification and microphysical properties in clouds. Using the dual-polarization Doppler radar with the hydrometeor classification algorithm and lightning observation, radar-derived microphysical properties related to lightning flash rate were investigated in terms of 10 isolated thunderstorm cases over the Kanto Plain, Japan, with 351 radar volume scans conducted every 5 min during the summer period. In this study, the ice-related particles within the 35 dBZ volume (V35IC) showed the highest correlation coefficient (r = 0.75) and the lowest normalized root mean square error (NRMSE = 8.3%) in relation to cloud-to-ground lightning (CG), and also best to intra-cloud lightning (IC, r = 0.69, NRMSE = 8.1%). The correlation between V35IC and CG flash rate was better than that of the mixed-phase (between 0 °C and − 40 °C) 35 dBZ volume (r = 0.64), without considering the microphysical particles. The second-best radar-derived microphysical property was the ice mass consisting of the radar grids of all the ice-related particles (r = 0.72). These results suggest that an effective lightning indicator in terms of a radar-derived property is the ice-related particle volume, in addition to the traditionally used graupel and hail. The ice-related particle volume in the colder region of the thunderstorm (air temperature lower than −10 °C) showed a higher correlation with CG and IC than that in the warmer region, especially in terms of IC. These results are consistent with the non-inductive charging theory that has been well accepted in previous studies. Following time-lag correlation analysis from 0 to −30 min every 5 min before thunderstorm initiation, it was found that the ice-related index of V35IC demonstrated the slowest decrease (r = 0.75–0.65 in 30 min) in the correlation coefficient with time lapse and may be suitable as a lightning nowcast indicator.

中文翻译：

---

双极化雷达得出的闪电频率与冰相关体积的关系

摘要 为了进行准确的闪电预测和临近预报，明确云中带电与微物理特性之间的关系非常重要。使用双极化多普勒雷达结合水凝物分类算法和闪电观测，对日本关东平原上空的 10 次孤立雷暴案例进行了雷达衍生的与闪电频率相关的微物理特性的研究，每 5 次进行 351 次雷达体积扫描。 min 在夏季期间。在这项研究中，与云对地闪电相关的 35 dBZ 体积 (V35IC) 内的冰相关粒子显示出最高的相关系数 (r = 0.75) 和最低的归一化均方根误差 (NRMSE = 8.3%) (CG)，也最适合云内闪电（IC，r = 0.69，NRMSE = 8.1%）。V35IC 与 CG 闪速之间的相关性优于混合相（0°C 和 - 40°C 之间）35 dBZ 体积（r = 0.64），不考虑微物理颗粒。第二好的雷达微物理特性是由所有与冰相关的粒子的雷达网格组成的冰块 (r = 0.72)。这些结果表明，除了传统使用的霰弹和冰雹之外，就雷达衍生属性而言，一个有效的闪电指标是与冰有关的粒子体积。雷暴较冷区域（气温低于-10°C）的冰相关粒子体积与CG和IC的相关性高于温暖区域，尤其是在IC方面。这些结果与先前研究中已被广泛接受的无感充电理论是一致的。