基于WRF-Chem对成都地区一次重度雾霾过程的模拟研究

A WRF-Chem Simulation on a Severe Haze Process in Chengdu

摘要: 本文使用ERA-I再分析数据驱动新一代大气预报模式Weather Research and Forecasting Model with Chemistry V3.9 (WRF-Chem V3.9)对2017年1月22~25日发生在成都的一次重度雾霾过程进行数值模拟研究，在使用观测数据检验模式性能后，对比了全球排放源和清华大学排放源等不同人为排放源对模拟结果的影响，并探讨了大气化学过程对雾霾过程的影响。论文得出以下结论：两种不同排放源的模拟结果对PM_2.5、PM₁₀、CO、SO₂等大气污染物的模拟效果有待进一步改进，其中，采用清华大学源的模拟效果在模拟趋势和量级上优于全球排放源；两种不同排放源的敏感性试验输出的2 m气温模拟值与实测值的相关性较好，模拟误差在3℃~6℃以内，与控制性试验的模拟值相比，敏感性试验的模拟值偏低，体现了化学过程的降温效应；含有化学过程的模拟有使2 m气温，边界层高度，10 m风速，感热通量和潜热通量降低的趋势，表明大气化学过程使得风速减少，对流减弱，感热通量和潜热通量降低，边界层高度降低，从而使污染物浓度进一步增加，反映了大气化学过程与污染物浓度的正反馈关系。相较于全球源的结果，采用清华大学源的敏感性试验结果更明显。

Abstract: This paper uses ERA-I reanalysis data to drive a new generation of atmospheric forecasting model, Weather Research and Forecasting Model with Chemistry V3.9 (WRF-Chem V3.9). In a severe haze process in Chengdu on January 22~25, 2017, numerical simulation studies were carried out. After using the observation data to test the performance of the model, the effects of different anthropo-genic emission sources such as global emission sources and Tsinghua University emission sources on the simulation results were compared, and the effects of atmospheric chemical processes on the haze process were discussed. The paper draws the following conclusions: the simulation results of two different emission sources for the simulation of PM_2.5, PM₁₀, CO, SO₂ and other atmospheric pollutants need to be further improved, in which the simulation effect of Tsinghua University source is used in the simulation trend and magnitude, it is superior to the global emission source; the 2 m temperature simulation value of the sensitivity test output of two different emission sources has a good correlation with the measured value, and the simulation error is within 3˚C - 6˚C. Compared with the simulated value of the control test, the simulation value of the sensitivity test is low, which reflects the cooling effect of the chemical process. The simulation with chemical process has the tendency of 2 m temperature, boundary layer height, 10 m wind speed, sensible heat flux and latent heat flux, indicating atmospheric chemical process. The wind speed is reduced, the convection is weakened, the sensible heat flux and the latent heat flux are reduced, and the boundary layer height is lowered, so that the pollutant concentration is further increased, reflecting the positive feedback relationship between the atmospheric chemical process and the pollutant concentration. Compared with the results of global sources, the sensitivity test results of Tsinghua University sources are more obvious.