We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest...We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity （RH） were simulated well （mean biases are 0.2K and 2.7%, respectively）, but wind speeds were overestimated （mean bias is 0.5 m.s -1）. At the Beijing station, sulfur dioxide （SO2） concentrations were overpredicted and sulfhte concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide （NO2） on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulthte concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO, substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS （heterogeneous oxidation by NO2） case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain （NCP） are mostly due to errors in SO2 emission inventory.展开更多
文摘We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity （RH） were simulated well （mean biases are 0.2K and 2.7%, respectively）, but wind speeds were overestimated （mean bias is 0.5 m.s -1）. At the Beijing station, sulfur dioxide （SO2） concentrations were overpredicted and sulfhte concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide （NO2） on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulthte concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO, substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS （heterogeneous oxidation by NO2） case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain （NCP） are mostly due to errors in SO2 emission inventory.
