Study of Influence of Aerosol on Atmospheric Visibility in Guanzhong Region of Shaanxi Province

To further study the influence of air pollution on atmospheric visibility,using the products of aerosol optical depth( AOD) of MODIS,the observed visibility data at 43 meteorological stations,and measured AOD using CE318,wind speed,relative humidity and visibility data at Jinghe in Xi'an,the relationship between the distribution of MODIS /AOD and visibility,the relationship between MODIS /AOD and the days of visibility less than 10 km in autumn and winter,and the relationship between MODIS /AOD and visibility under different wind speed,relative humidity,have been analyzed. The results show the distribution of MODIS /AOD is correspond well with the distribution of visibility. The correlation coefficient of MODIS /AOD and visibility at 08: 00 in winter and spring is better than other seasons. While the correlation coefficient of MODIS /AOD and visibility at 14:00 is better in summer and autumn. Air particulate pollution is the most important factor which causes lower visibility in autumn and winter except precipitation. When ngstrom range from 0. 8 to 1. 2,aerosols impact on visibility distinctly. The deterioration of visibility caused by air polluted is closely related with relative humidity,higher relative humidity causing more visibility decline. When wind speed is lower,particles in air accumulate easily and lead to visibility deterioration. When wind speed is higher,air pollutants diffuse easily and the visibility improve quickly. Estimating visibility using AOD must consider the influence of relative humidity and wind speed on them.