We show, for the first time over Italy and over part of the central Mediterranean Basin, the impact of lightning data assimilation (LDA) on the strokes forecast for a long period. We use the Weather Research and Forecasting (WRF) model coupled with the Dynamic Lightning Scheme (DLS) at convection allowing horizontal resolution (3 km). We carried out a two-seasons experiment (summer 2020 and fall 2021) providing the forecast of lightning and precipitation for the next 6 h (nowcasting), considering two sub-periods (0-3 h and 3-6 h) for verification. The LDA is done through a nudging scheme that increases the water vapor mass in the mixed-phase region based on observed flash density rates and simulated graupel mixing ratio. No changes are made to the model run if spurious convection is predicted or no flashes are observed. LDA can trigger convection missed by the control forecast, without LDA, and/or can redistribute the strokes predicted to be more consistent with observations. LDA has a positive impact on strokes forecast, improving correct forecasts and reducing false alarms. This improvement is however confined to the first three-hours of forecast with negligible to negative impact for longer time ranges, in line with other studies. The improvement pattern is different in summer and fall, depending on the convection development.

中文翻译：

---

利用 WRF 模型和闪电数据同化改进闪电预报：意大利两季数值实验的结果

我们首次在意大利和地中海盆地中部部分地区展示了闪电数据同化 (LDA) 对长期中风预测的影响。我们在对流条件下使用天气研究和预报 (WRF) 模型以及动态闪电方案 (DLS)，允许水平分辨率（3 公里）。我们进行了两个季节的实验（2020年夏季和2021年秋季），提供未来6小时的闪电和降水预报（临近预报），考虑两个子时段（0-3小时和3-6小时）进行验证。 LDA 是通过微推方案完成的，该方案根据观察到的闪蒸密度率和模拟的霰石混合比增加混合相区域中的水蒸气质量。如果预测到虚假对流或没有观察到闪光，则不会对模型运行进行任何更改。在没有 LDA 的情况下，LDA 可以触发控制预测错过的对流，和/或可以重新分配预测的中风，以与观测结果更加一致。 LDA 对卒中预测具有积极影响，可提高正确预测并减少误报。然而，根据其他研究，这种改善仅限于预测的前三个小时，在较长时间范围内的负面影响可以忽略不计。夏季和秋季的改善模式有所不同，具体取决于对流发展情况。