Abstract:

Haze is traditionally an atmospheric phenomenon where dust,smoke and other dry particles obscure the clarity of the sky,and it has important effects on the social economy and human health.Based on the daily average relative humidity,visibility and weather information 〖JP2〗of 11 Shanghai meteorological〖JP〗 sites from 1960 to 2008,climate data series of haze days over the past 50 years in Shanghai were reconstructed and the spatial and temporal characteristics and change of the number of haze days was analyzed with the method of climate statistics.The results showed that reconstructed data of haze days was pretty consistent with the records from surface meteorological observation report forms,and the change of reconstructed data was more stable.From 1960 to 2008,the number of haze days in Shanghai was significantly increasing with a linear trend of 97 d/10 a,while after 2002,the number decreased overall.The average number from 1960 to 2008 was the maximum in winter and the minimum in summer.During the past 50 years,the spatial distribution of haze days was the most in the southwestern part,more in the urban areas and the least in the northeastern and southeastern parts of Shanghai,while the spatial trend of haze days was increased more in the southwestern part and less in the eastern part.During the period from 1981 to 2008,the number of haze days 〖JP2〗increased in both the western part and the southern parts,but decreased in the eastern part of Shanghai.〖