Abstract:

In order to further understanding the characteristics of fog in the region around the Three Gorges Reservoir，this paper studied the climate changes of extreme fog which last 12 hours and 3 days,discussed the possible reasons of the fog changing by using linear trend estimates and moletwavelet analysis.The results show that,the annual mean fog days in the region around the Three Gorges Reservoir shows a weak downward trend and there are decadal oscillations of 8,18 and 32 years.Extreme fog lasting 12 hours and 3 days shows a significant increasing trend,and there are decadal oscillations of 10,17,32 years and decadal oscillations of 12,32 years,respectively. The annual mean fog days  in west section of the Three Gorges Reservoir significantly reduced,but increased in  east section after impoundment.The annual mean fog days of extreme fog lasting 12 hours changes little after impoundment,but the annual mean fog days of extreme fog lasting 3 days significantly reduced after impoundment.The reduction of foggy days in Three Gorges area is affected by the results of global warming and urbanization,and there is no evidence that the impoundment in three Gorges area have influence on the fog