ANALYSIS OF THE TREND OF VISIBILITY CHANGE IN THE LAST 30 YEARS AT FOSHAN
Zhang Jun(Air force Meterology College)
In this paper, the hours of the visibility Abstract. 4 or 10 km every season are counted in the last 30 years at Foshan. It is found that the hours of the visibility≥.4 or 10km every season are remarkably ascented in the model of the exponential function in the last 30 years. It is also found that there is no remarkable change trends in the relative humudity so the visibility change trends are not in relation with the relative humudity. There is the greatest in the frequencies of the visibilty .≤4 and their increase in the last 30 years in the calm every season, the second greatest in the downwind of the city, and the smallest in the weatherside of the city. It is noticed theat the hours of the calm every season are added in the last 30 years. So the visibility change trends at Foshan are relative with the wind directions.