Observational study of atmospheric visibility in summer in the area of multi-cities in central Liaoning Province

Using the observational data of 4 cities in central Liaoning Province from June to August, the mean seasonal, monthly and daily characteristics of visibility is analyzed in this paper. In addition, the diurnal visibility and influence factors are also studied. The results indicate that each city in the area of multi-cities in central Liaoning Province shows the same trend of monthly visibility variety. The weather system and atmospheric environment has generally uniform and regional features.Daily visibility variety of each city presents the distribution of single period peaks and valleys in which the lowest valueis are at 06:00 BT and the highest ones at 15:00-16:00 BT. Furthermore, fine particles, vapor and wind speed all have effects on visibility, among which fine particles are the major factor. Only a small part of the low visibility duration is due to slight fog. It is the haze that causes most of the low visibility events in the area of multi cities in central Liaoning Province.