Periodic Characteristics of Fog Visibility in Guanghan Airport

Based on the hourly diurnal meteorological visibility data of Guanghan airport from 1986 to 1995, the periodic variation characteristics of the visibility, such as diurnal, monthly, seasonal and intra-seasonal variations, are studied, in which the correlation analysis method, power spectrum analysis, Band-pass filter, Wavelet analysis method are used.The results indicate that there is a significant inverse correlation between the variation of visibility of Guanghan airport and the relative humidity as well as the low cloud cover.However, the visibility becomes good when the temperature and wind speed increase.What's more, the periodic variations of quasi 2-weeks oscillations (10-20d) and quasi intra-seasonal oscillations (30-50d) have important implications for understanding the development and persistence of low visibility.