Weather situation classification and its correlation with atmospheric pollutant in Fuzhou, Fujian province

Based on the ground synoptic chart and the upper-air chart of 500 hPa from 2002 to 2006, the weather situation types controlling Fuzhou weather were divided into 10 types. The frequencies of different weather situation types in the whole year, winter half year and summer half year and the corresponding pollutant concentrations were analyzed in Fuzhou. The atmospheric diffusion abilities under the different weather situations and their effects on pollutant concentrations were discussed. The results indicate that the warm sector ahead of the fronts and the ground inverse trough are the disadvantages to the atmospheric diffusion. However, typhoon (Inter-Tropical Convergent Zone, ITCA) and low vortex front are advantageous to the atmospheric diffusion. During winter half year, the effects of the back of high pressure and the warm sector ahead of fronts as well as ground inverse trough on increasing pollutant concentrations are larger, while the effects of low vortex front and high pressure ridge as well as the base of high pressure on decreasing pollutant concentrations are larger. During summer half year, the effects of typhoon (ITCA) and low vortex front as well as subtropical high pressure on decreasing pollutant concentrations are larger, and the pollutant concentrations take on the positive values under other weather types.