华东三市能见度、气溶胶和太阳辐射变化特征

Variations of Visibility,Aerosol Optical Depth and Solar Radiation in Three Cities over East China

利用南京、杭州和合肥3个台站1961—2001年能见度和水汽压资料,反演3个城市0.55μm气溶胶光学厚度(AOD),并据此分析了这3个城市的能见度和气溶胶光学厚度的变化特征;利用太阳辐射资料分析太阳辐射变化特征,并与气溶胶光学厚度变化特征作对比。结果表明,在1961—2001年间,这3个城市的能见度呈现明显下降的趋势,南京和杭州下降最快,合肥下降较慢,并且具有明显的季节性差异,夏季最大,冬季最小。气溶胶光学厚度则呈现上升趋势,增加最快的是南京,最慢的是合肥。按季节划分来看,春夏较高,秋冬较低。1990年之前,这3个地区的总辐射和直接辐射都呈现明显的下降趋势,散射辐射的变化趋势不显著,而1990年后,南京与合肥的总辐射略有回升。辐射季节总量按由多到少依次是夏季、春季、秋季和冬季。气溶胶光学厚度与直接辐射间有较好的负相关性。

Using the data of visibility and vapor pressure measured in Nanjing,Hangzhou,and Hefei from 1961 to 2001,the 0.55 μm aerosol optical depths(AOD) of these areas are inverted,and the variation characteristics of visibility and AOD are analyzed.In addition,the variation characteristics of solar radiation from routine radiation measurements are analyzed and compared with the variation characteristics of AOD.The results shows that the visibility over these three cities had significant decreasing trends from 1961 to 2001;the fastest decrease of visibility appeared in Nanjing and Hangzhou,while the slowest in Hefei.Visibility had also seasonal variation,maximum in summer and minimum in winter.AOD not only showed increasing trends,fastest in Nanjing and slowest in Hefei,but also had seasonality,higher in spring and summer,lower in autumn and winter.The global radiation and direct radiation had a significant decline in all the three cities before 1990,while the diffuse radiation did not change obviously.However,a slight increasing trend of global radiation was found in Nanjing and Hefei after 1990.Seasonal total of radiation is in the following descending order: summer,spring,autumn,and winter.A negative correlation between AOD and direct radiation has been found.