Modeling study of the ground-based cloud seeding experiments in mountainous area

The Weather Research and Forecast model coupled with chemistry mechanism and aerosol modules (WRF-CHEM model) was used to investigate the effect of the cloud seeding on precipitation. This model was performed for the ground-based cloud seeding experiment in mountainous area using CBMZ chemistry mechanism and MOSAIC aerosol modules. The input and the boundary conditions of model were improved using KLAPS (Korea Local Analysis and Prediction System) in 5 km resolution reanalysis data. Both seeded and un-seeded cases were simulated for three cloud seeding experiments (from 00 UTC to 12 UTC on 12, 17, and 27 February in 2011) with 1 km resolution. The seeding material (PM_2.5, nuclei mode in WRF-CHEM) was assigned into two grid points near the Daegwallyeong cloud physics observatory in mountainous area. The seeding rate was 10⁴ µgm^-2s^-1 in seeded case. The seeding material was diffused by wind direction and the CCN was increased over the analysis area in simulated seeded case. The result of the seeded case showed the variation of precipitation, compared with those of un-seeded case. Precipitation amounts and some microphysical variables (cloud water, rain, and graupel) were temporarily increased at two experiments on 12 and 27 February. However, precipitation amounts were decreased at the experiment on 17 February. Thus, the experimental weather condition has influenced on the success of cloud seeding experiment. These simulation results illustrate the difficulty of finding the suitable weather conditions and the seeding time for a successful precipitation enhancement at the target area.

Acknowledgement : This work was supported by the “Advanced Research on Applied Meteorology” of National Institute of Meteorological Research (NIMR) funded by the Korea Meteorological Administration (KMA).