Performance Evaluation of the WRF-Chem Model with Different Physical Parameterization Schemes during an Extremely High PM2.5 Pollution Episode in Beijing

Abstract

To understand the impacts of different combinations of planetary boundary layer (PBL), short-wave (SW) and longwave (LW) radiation schemes on the simulation results of meteorological variables and PM 2.5 concentrations under extremely heavy pollution conditions, the Weather Research and Forecasting model with Chemistry (WRF-Chem) model was applied in Beijing to investigate a high PM 2.5 pollution episode that occurred in January, 2013. Four PBL schemes, two SW schemes and three LW schemes with a total of 12 ensemble experiments were conducted in this study. The simulated meteorological variables including the temperature at 2 m (T2), the wind speed at 10 m (WS10) and the relative humidity (RH) were compared with their actual observations and the PM 2.5 concentrations. A correlation analysis between the PM 2.5 and T2, WS10 and RH values was also explored. The results indicated that there were no ideal scheme combinations that were most suitable for all meteorological variable simulations during this heavy pollution episode in Beijing. With the same emissions input, the simulation results of the WRF-Chem model that were configured with different physical parameterization schemes may vary significantly. As for the PM 2.5 simulation, the combination of the YSU PBL, Goddard SW and GFDL LW schemes showed the greatest consistency with the observed values. Although the PBL schemes have the dominant impacts on the simulations of meteorological variables, the selection of LW and SW schemes is of the same importance.

WRF-Chem simulation of aerosol seasonal variability in the San Joaquin Valley

“…Chow et al, 2006;Herner et al, 2006;Pun et al, 2009;Ying and Kleeman, 2009;Zhang et al, 2010;Chen et al, 2014;Hasheminassab et al, 2014;Kelly et al, 2014;Baker et al, 2015;Brown et al, 2016). CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) and IM-PROVE (Interagency Monitoring of Protected Visual Environments) observations show that dust is a primary contributor to the aerosols in the SJV, especially in the warm season.…”

“…The Yonsei University (YSU) planetary boundary layer (PBL) scheme (Hong et al, 2006) is used in all of the simulations, except one sensitivity experiment that uses the ACM2 (Asymmetric Convective Model with non-local upward mixing and local downward mixing; Pleim, 2007) PBL scheme (referred to as "20km_P7" hereafter, Table 1). Previous studies showed that both the YSU and ACM2 schemes have good performance in simulating boundary layer properties (e.g., Hu et al, 2010;Xie et al, 2012;Cuchiara et al, 2014;Banks and Baldasano, 2016;Banks et al, 2016;Chen et al, 2017). Sub-grid convection, convective transport of chemical constituents and aerosols, and wet deposition from sub-grid convection are parameterized using the Grell 3-D ensemble cumulus scheme (Grell and Devenyi, 2002) in the 20 km simulations, while convective processes are resolved in the 4 km simulations.…”

PM2.5 Estimation with the WRF/Chem Model, Produced by Vehicular Flow in the Lima Metropolitan Area

“…This parameter in the studies carried out in the summer season by [65] and [60] were −31.84% and −18.5% respectively. The mean normalized bias (NMB) in [73].…”

Sensitivity Analysis of Chemical Mechanisms in the WRF-Chem Model in Reconstructing Aerosol Concentrations and Optical Properties in the Tibetan Plateau

“…This model significantly reduces the inconsistency between meteorological and chemical processes and also takes feedback effects related to aerosol into account (Zhang et al, 2010;Chen et al, 2017). Nevertheless, the accurate modeling of aerosol feedback effects requires a reliable reproduction of the main driving process of the fate of atmospheric aerosols.…”