Abstract:

The near-surface temperature has an important influence on the diffusion and transfer process of airborne radioactive materials.Global weather forecast products are important basic data and initial conditions for the diffusion model and air quality model.Their errors directly affect the accuracy of simulation results.In order to investigate the errors of different products, three kinds of global weather forecast products, the GFS (Global Forecast System), ECMWF (European Medium-Range Weather Forecast Center), and T639 were selected from June 2016 to May 2017.Using the observational data from 2100 ground stations in China, the near-surface temperature of the forecast products was compared and analyzed, and their performance characteristics in different seasons and regions were investigated.The results show that the temperature forecast of the three meteorological products in China tends to be lower.The annual mean value of RMSE (Root mean square error) is between 2.60 ℃ and 3.52 ℃.The annual mean value of the correlation coefficient is between 0.89 ℃ and 0.92 ℃.The annual mean value of the average absolute error is between 1.87 ℃ and 2.67 ℃.Overall, the performance of ECMWF is the best, followed by the GFS and T639.The temperature prediction error is different at different seasons.Based on the RMSE and mean absolute error of the three products, it indicates that the performances in summer and autumn are better.While based on the correlation coefficient, it shows that the performances in autumn and winter are better.There are obvious regional differences in temperature forecast errors.The spatial distribution characteristics in the temperature forecast errors from the three weather forecast products are similar.The error values are lower in the east of China and higher in the southwest of China.At the same time, the error is lower in the coastal areas and higher in the inner land areas.

Key words: Global numerical weather forecasting products, Near-surface temperature, Short-term forecast