Abstract
The current study conducted numerical experiments using nonhydrostatic mesoscale meteorological model to clarify the mitigating e.ect of weather modification by cloud seeding on torrential rains. Based on simulated two heavy rain events in northern Kanto and Tokai regions of Japan, sensitivity analysis was performed by manipulating some conditions for cloud seeding implementation, i.e., area, height, time, etc., in incremental steps. Variations of rainfall distribution and convective cloud activity were examined to see the in.uence on the generation and development process of torrential rains. Results in some cases show a signi.cant decrease in areal average and/or regional maximum rainfall, especially noticeable in the case where cloud seeding was performed at a relatively high altitude. It suggests that weather modification by cloud seeding can weaken the development and convergence of torrential rains. In the case with such a decrease in regional maximum rainfall, a signi.cant increase of cloud ice was found in the upper part of the atmosphere, which seems to have caused the mitigation in the spatial and temporal convergence of precipitation particles falling to the ground.
