Abstract
In the backdrop of a significant improvement in weather prediction with Numerical Weather Prediction models, quantitative prediction of the intensity of heavy rainfall events and associated disasters has remained a challenge. Encouraged by the recent emergence of compelling observational evidence for a significant electrical influence on cloud/rain microphysical processes (Mudiar, Pawar, Gopalakrishnana et al., 2021, https://doi.org/10.1029/2021gl093577), here we propose a hypothesis that the modification of the raindrop size distribution (RDSD) towards larger drop sizes facilitated by cloud electric fields could be one factor responsible for realistic rainfall intensity in weather/climate models. The robustness of the proposed hypothesis is confirmed through a series of simulations of strongly electrified rain events with the Weather Research and Forecasting model incorporating the electrically modified RDSD parameters in the model physics. Our results indicate a possible roadmap for improving hazard prediction associated with extreme rainfall events in weather prediction models.
Plain Language Summary
Lightning and heavy precipitation events in the tropics have significant socio‐economic implications in regard to disaster management. The accurate prediction of these meteorological events has remained a challenge despite considerable improvement in the Numerical Weather Prediction model over the years. With convincing observational evidence of a significant impact of the cloud electric field on the raindrop size distribution (RDSD) in the background, here we have attempted to test the model fidelity to simulate rain events with a strong in‐cloud electrical environment using the Weather Research and Forecasting model. A significant underestimation of the observed rain intensity is noted for the rain events that are associated with lightning. A possible roadmap has been discussed to improve the observed dry bias of rainfall by incorporating the electrically modified raindrop RDSD parameters in the model physics. Substantial improvement in the rain intensity has been observed with the incorporation of electrically modified RDSD parameters.
Key Points
Cloud electric field substantially modifies the raindrop size distribution in strongly electrified clouds
Weather Research and Forecasting model simulations show a significant underestimation of the observed rain intensity for strongly electrified rain events
The simulated rain intensity improved significantly with the incorporation of electrically modified raindrop size distribution parameters