The Aerosol Effects on Cloud Properties and Precipitation in a Numerical Forecasting Model

Atmospheric aerosols play an important role in cloud formation by acting as cloud condensation nuclei (CCN). CCN alters characteristics and optical properties of cloud, such as cloud droplet number concentration, effective radius of hydrometeors, cloud liquid/ice path, and cloud lifetime causing change of precipitation. WRF Double-Moment 6-class microphysics scheme is implemented in KIAPS integrated model to simulate aerosol indirect effect. The microphysics, cumulus parameterization, and radiation schemes are modified to explicitly consider aerosol properties. Aerosol properties are calculated by simplified chemistry model coupled with the KIAPS integrated model. The convective precipitation rate decreases as the number concentration of CCN increases. On the contrary, the non-convective rainfall dose not decrease linearly owing to interaction between hydrometeors and change of temperature. Skill scores of the simulated precipitation in a medium-range forecast testbed confirm the benefits of treatment of aerosol-cloud interaction.