辽宁中部城市群大气能见度变化趋势及影响因子分析

Analyses on Variation Trends of Atmospheric Visibility and Its Effect Factor in Muilt-Cities in Central Liaoning

通过分析辽宁中部相对集中分布的5个城市群1987—2002年间的大气能见度、影响能见度的气象因子和污染物的变化特征及能见度与气象因子、污染物浓度之间的相关关系等,得到以下结论:(1)各城市能见度有明显的月、季和年际变化特征,能见度月变化呈双峰型,第一个峰值在5月份,第二个峰值在9,10月份;冬季能见度的值最低,春、秋季高;本溪市的能见度在逐年变好;沈阳的能见度从1987—1997年逐年变好,1997年以后又逐年变差;其它城市的能见度呈逐年变差的趋势。(2)各城市影响能见度的气象因子的年际变化特征基本是一致的;5个城市TSP,SO2污染浓度年均值均呈下降趋势,NOX的年际变化趋势不明显。(3)能见度与湿度、雾的相关关系都呈负相关且非常显著;与降雨量、风速及温度之间的关系比较复杂;与各种污染物的相关都呈负相关。

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, SO2 in 5 cities all have the decreasing trend, the interannual change of NOx 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 andpollutant is negative.