Research on the Selection of the Optimal Observations and Radius of Circular Interpolation during Objective Verification of Sand-Dust Forecasts

Utilizing the ground sand concentration net grid products forecasted by the China Meteorological Administration (CMA) Unified Atmospheric Chemistry Environment (CUACE) numerical model, human forecasts of sand-dust rank products, observed ground sand-dust rank, and the observed particulate pollution (PM10), this paper calculated the Threat Score (TS) from 2012 to 2014, which contained a total of 25 processes of sand-dust weather, to select the best observations and radii of circular interpolation for an objective verification of the sand-dust forecast. For the net grid CUACE numerical model products, different radii were chosen by using the circular interpolation to generate the interpolated station sand-dust forecast. Several conclusions were drawn from the study results (1) For the sand-dust rank observations, the radii approximately linearly declined with TS in the float dust-dust rank; the TS rarely changed when the radius changed in the sand-dust rank above the sandstorm, and the best radius selected was the minimum radius, i.e., 0.5° (longitude/latitude). For the PM10, the TS changed markedly when the radius changed in the float dust, but rarely changed when the radius changed in the sand rank above the sandstorm, when the best radius selected averaged 3.5°. If the sand was very weak, the radius could be properly decreased to 1°. (2) For the CUACE numerical model product, the usability of the TS of the observed sand-dust rank was better than the observed PM10, while the two were nearly the same in rank above the sandstorm. Thus, the best observation used for the objective verification of the CUACE numerical model product, generally, was observed ground sand rank. For the human sand rank forecast, the TS of the observed ground sand-dust rank was much higher than the PM10, and the best observation for the verification was the observed ground sand rank.