Numerical Simulation of Hygroscopic Seeding Experiment over the Korean Peninsula Using WRF Model with Hygroscopic Seeding Parameterization

In order to solve severe drought problem, cloud seeding experiments are being carried out in many places around the world. In Korea, precipitation is mostly concentrated in the summer season but often times severe drought occurs in the spring season. For this reason, continuous efforts are being made to solve this springtime drought problem through precipitation enhancement experiments. It is found that hygroscopic seeding is more suitable for many of the clouds observed in spring in Korea. However, the effects of the seeding experiments are difficult to confirm quantitatively through field observations. For this reason, in this study we devise a method to parameterize hygroscopic flare (CaCl₂) seeding process and apply it to simulate hygroscopic seeding experiments in the Korean Peninsula, using WRF (Weather Research and Forecasting model). In detail, activation of hygroscopic seeding material is calculated either in the droplet activation process or in the auto-conversion process of Morrison microphysics scheme, depending on the size of hygroscopic flare particles: in the activation process for diameter of flare particles smaller than 10 μm and in the auto-conversion process otherwise. Using this modified scheme, this study attempts to confirm the seeding effect of precipitation enhancement experiments quantitatively and tries to improve our understanding of the mechanism of precipitation development in the hygroscopic seeding experiment. Finally, we will try to suggest a guideline for optimal precipitation enhancement experiments. Detailed results will be discussed at the conference.