Assessment of the simulated aerosol optical properties and regional meteorology using WRF-Chem model

The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) has been used to simulate aerosol optical properties and meteorological parameters including rainfall over Pakistan during July 2016. Two identical experiments are designed for simulation. The first one is based on WRF-Chem simulation with feedback from aerosols’ direct and indirect effects, whereas the second one does not include any aerosol effect. The robustness of the model simulations are examined against the data sets obtained from satellite- and ground-based observations. Different meteorological parameters, e.g. temperature, relative humidity, pressure, rainfall distribution, and aerosol optical properties, e.g. aerosol optical depth (AOD), aerosol extinction coefficient, and single scattering albedo (SSA), are simulated reasonably well. The magnitude and spatial distribution of AOD is simulated realistically over the study domain, particularly over eastern and northeastern parts with high aerosol burden due to natural and anthropogenic aerosols. The net atmospheric forcings due to both short waves (SW) and long waves (LW) and the resultant atmospheric heating simulated by the model are positive over the entire study domain with higher values over the northeastern part. It is shown that the rainfall magnitude is reduced by the inclusion of feedback from aerosol direct and indirect effects into the model simulation over different parts of the study area. © 2021, Saudi Society for Geosciences.