Research On The Impact Of Optimization Of Underlying Surface Information On The Simulation Of The Beijing-Tianjin-Hebei Meteorological Field And Air Pollutant Concentration Field

The accuracy of air quality model prediction is affected by many factors,among which the data of underlying surface such as terrain height and land use,plays an important role in air quality simulation.They influence meteorological factors and the diffusion of pollutants by affecting the surface energy balance through different surface physical parameters.So improving the accuracy of the underlying surface data,which is one of the important factors to affect the accuracy of pollutant concentration and diffusion simulation process,can predict the air quality more accurately in the simulated area.In this study,the terrain interpolation module part of WRF model was modified to improve the accuracy of the air quality model simulation.Compared with the traditional"Original file update method",the underlying surface data using the new correction method can be directly input to the meteorological field without system interpolation,and to avoid simulation errors caused by system interpolation.SRTM terrain height data and MODIS2016 land-use data were selected as the high resolution underlying data in this study,to verify the impact of the new optimization method on the meteorology and air quality simulation compared with the default method and the"Original file update method"in the Beijing-Tianjin-Hebei region during 2016.It was found that the"Direct correction method"has a better effect on simulation results.The main research contents are as follows:?1?We found that the WRF needs to interpolate the underlying data during operation,which results in system interpolation error in the underlying data,and the error will increase as the grid width increases.This is the default method of the model and"Original file update method"can not be avoided,so in order to solve this problem,the terrain interpolation module was corrected,and the underlying surface"Direct correction method"replacement method was proposed.?2?The new correction method and the traditional method were used to compare and verify 2m pressure,2m temperature,10m wind speeds,2m relative humidity,and 2m dew point temperature on the results of meteorological simulation in Beijing-Tianjin-Hebei region.The meteorological elements simulated by"Direct correction method"were better than the results of the default method and"Original file update method".The bias between the simulated values of pressure,temperature,wind speed,and relative humidity were obviously improved.In the time series,the trends of the simulated values and the observed values were the same.The results of the"Direct correction method"were closer to the observed values.?3?The improvement on the air quality simulation was evaluated in order to further verify the advantages of the new correction method.The concentrations of PM_2.5,NO₂,SO₂,and CO were verified and it was found that"Direct correction method"has a greater improvement effect on them.Pollutant concentration simulated bias were significantly reduced compared with the other two methods,,and the degree of improvement on heavy pollution days was greater than on clean days.?4?From the perspective of relative spatial changes,the concentrations of PM_2.5,NO₂,SO₂,and CO simulated on the basis of"Direct correction method"showed a significant increase in the southern region of Hebei Province,which was in accordance with the actual heavily polluted areas.The"Direct correction method"simulaed values were significantly reduced in the time series,with the frequency and number of peaks reducing.