Variation Characteristics of Sunshine during 1959-2008 in Dabancheng

Based on observation data of the sunshine hours,percentage of sunshine,total/low cloud cover,precipitation days with precipitation ≥0.1mm,fog,sandstorm,blowing sand,floating dust etc.in Dabancheng weather station from 1959 to 2008,this paper analyzed the variation characteristics of sunshine hours in recent 50 years with method of linear analysis.The results indicated that the sunshine hours revealed a fluctuated increasing trend with the climate tendency rate of annual sunshine hours 37.62 h/10a,thereinto it represented fastest increase in spring and autumn.There was close correlation between sunshine hours,total/low cloud cover and precipitation days with ≥0.1 mm precipitation.The decrease of total cloud cover was the main reason for the variation of sunshine hours there,whereas the increase of precipitation days and foggy days had not much impact on sunshine.Weather of dust storm,blowing sand and floating dust influenced the sunshine hours slightly since it showed a decreasing trend in recent 50 years with a very small annual probability of happening.