An Analysis of Multi-time Scale Variability of Fog and Haze Visibility in Shanwei City

The conventional meteorological data from 1961 to 2003 are used to analyze the multi-time scale variability of fog and haze visibility in Shanweil City.The results show that: as for the time and frequency change of fog and haze visibility in Shanwei,the maximum value occurred at 8∶00,then declined gradually from 8∶00 to 14∶00,and the minimum value at 14∶00;the monthly change of fog and haze visibility is not obvious,the fog mainly appeared in winter and spring,especially in spring;the frequency of haze increased obviously after the 1980s and that of fog increased after the 1970s,but the annual change of the fog was not evident.The main reason might be that the pollution of the city was increasing year by year,and consequently the frequency of the fog and haze increased obviously.