Implementation of WRF/Chem Aerosol Scheme in KIAPS-GM and Evaluation of Aerosol Radiative Forcing

Aerosol affects atmospheric radiation budget by scattering and/or absorbing radiation, and modifying cloud properties. The GOCART (Goddard Chemistry Aerosol Radiation and Transport) aerosol scheme of WRF/Chem was implemented in KIAPS-GM (Korea Institute of Atmospheric Prediction Systems-Global Model) to assess the effect of aerosols on radiation budget and weather.

The KIAPS-GM is a global model with the element-based dynamical core on cubed-sphere grids. The initial version of physics package as a part of the KIAPS-GM includes the RRTMG (Rapid Radiative Transfer Model for GCMs) radiation, prognostic cloud macrophysics, single-moment microphysics, mass flux convection, PBL with k-profile closure, simple gravity wave drag scheme, and Noah land surface model. The simulated aerosol concentrations by GOCART aerosol scheme on-line coupled with KIAPS-GM are used for the calculation of radiative direct forcing instead of using the climatological aerosol concentrations. The model calculated total aerosol optical thickness is compared with the satellite retrieval products from the Total Ozone Mapping Spectrometer (TOMS) and the Advanced Very High Resolution Radiometer (AVHRR), and the direct radiative forcing by aerosols is estimated globally. Sensitivity tests are also conducted to examine the radiative impacts of aerosols on meteorological fields by simulations with and without aerosols.