Analyses on Variation Trends of Atmospheric Visibility and Its Effect Factor in Muilt-Cities in Central Liaoning
MA Yan-jun~(1),ZUO Hong-chao~(2),ZHANG Yun-hai~(1),HUI Xiao-ying~(2) (1. Shenyang Atmospheric Environment Institute, China Meteorological Administration, Shenyang 110016, China; 2. Cold and Arid\=Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China)
Through analyzing the atmospheric visibility, meteorological factors influencing visibility, change features of pollutant, as well as the relation between the visibility and meteorological factors and pollutant concentration, the obtained results are as follows: (1) The visibilities in 5 cities have obvious the monthly, seasonal and yearly variation features. The monthly variation of visibility appears bi-peak patterns, the first peak value is in May, and second is in September or October. The value of visibility in winter is the lowest, and the hightest in spring or summer in a year. The visibility in Benxi became better in the past years, one in shenyang became better too from 1987 to 1997, but it is bad after 1997, one in other cities beccame worse in the same period. (2) The features of interannual change of meteorological factor influencing visibility in 5 cities are basically consistent with eath other, the yearly mean values of TSP, SO_2 in 5 cities all have the decreasing trend, the interannual change of NO_X is not obvious. (3) The correlation between visibility and humidity and fog is negative, and their correlation is very significant, the correlation between visibility and rainfall, wind and temperature is very complex, the correlation between visibility and the pollutant is negative.