Analysis of Atmospheric Turbidity in Clear Skies at Wuhan, Central China

The?ngstr?m turbidity coefficient (β)and Linke turbidity factor(TL)are used to study the atmospheric conditions in Wuhan,Central China,using measured direct solar radiation during 2010–2011 in this study.The results show that annual mean βvalues generally increase from 0.28 in the morning to 0.35 at noon,and then decrease to 0.1 in the late afternoon during the day;annual mean TLgenerally varies from 3 to 7 in Central China.Both turbidity coefficients have maximum values in spring and summer,while minimum values are observed in winter months.It also reveals that β values show preponderance(52.8%)between 0.15 and 0.35,78.1%of TLvalues are between 3.3 and 7.7,which can be compared with other sites around the world.Relationship between turbidity coefficients and main meteorological parameters(humidity,temperature and wind direction)have been further investigated,it is discovered that the local aerosol concentrations,dust events in northern China and Southwest Monsoon from the Indian Ocean influences the β values in the study area.