Abstract:

The worldfamous“Three Gorges Reservoir”is situated on the middle reaches of the Yangtze River. The fina1 water leve1 reaches 175meter and the reservoir covers 10000 km of region. It has more foggy days on the river because of the water bodies and special terrain, seriously affecting waterway. And the foggy days is becoming more and more dangerous in the Yangtze River waterway. With the support of the government of Three Gorges Project construction and China Meteorological Administration, 15 meteorological stations and 12 visibility instruments have been installed in 2009, in order to analyze the influence on the regional climate environment. In this paper, based on the meteorological data of 12 meteorological stations along the Yangtze River in the Three Gorges Reservoir Area, visibility of the Yangtze River waterway have been analyzed, in order to analyze the characteristics of visibility along the different regions of Three Gorges waterway, compare the influence of the different vertical sections and the distance from the river.The spatialtemporal distribution characteristics of visibility of Fuling, Wanzhou, and Yichang region have been discussed．It is found that the frequency distribution of visibility of Fuling has the greatest impact on the shipping safety, followed by Wanzhou and Yichang. The monthly variation trend of foggy days in Fuling and Wanzhou district is consistent. The variation within the year is 6 month period. The frequency of fog was more higher in May, June, November and December of the year. The monthly variation of fog is larger in Yichang district. The fog occurs at night and in the morning time, and the frequency peak generally appears in the morning. By verifying the relationship model of visibility and local factors, it showed that the visibility differences of the Three Gorges waterway were due largely to the altitude and water and topography of the monitoring points. The visibility is lower and foggy frequency is relatively higher if the altitude of monitoring points is higher or near the water, and vice versa.