[A-AS01] From Weather Predictability to Controllability

[AAS01-P03] Mitigating Convective Heavy Rainfall Through Targeted Cloud Seeding: A WRF Model-Based Study of the 2014 Hiroshima Event

*Jacqueline Muthoni Mbugua¹, Yusuke Hiraga¹ (1.Tohoku University)

Keywords:Senjou-Kousuitai, Hiroshima event, WRF model, Cloud seeding

An investigation of a targeted cloud seeding approach for mitigating heavy convective rainfall was conducted using the Weather Research and Forecasting (WRF) model. The model was first employed to reproduce the 2014 Hiroshima heavy rainfall event, which produced over 200 mm of precipitation in three hours and was largely driven by intense zonal moisture transport in the lower atmospheric layer. Building on this simulation, dry ice seeding experiments were performed to simulate overseeding in deep convective regions containing supercooled water. The intervention was designed to promote the formation of numerous small ice particles, effectively inhibiting the coalescence of droplets into larger aggregates that produce rain and snow. As a result, targeted seeding substantially modified the spatiotemporal evolution of convective clouds and rainfall, with effects that varied according to the precise location and timing of the seeding. Moreover, the estimated dry ice requirements fall within practical and cost-effective limits. These findings support the potential of targeted cloud seeding as a viable strategy for reducing heavy rainfall and highlight the need for further ensemble studies to elucidate the underlying physical mechanisms and optimize operational strategies.