Variation Characteristics of Sunshine Hours of Akto County in Recent 50 Years

By means of the observed data of sunshine duration in Akto County in recent 50 years,according to the data of precipitation,total cloud amount and low cloud amount in Akto County,the inter-decadal,inter-annual and seasonal climate change characteristics on sunshine hours are analyzed,and the climatic causes for the decreasing sunshine duration are discussed.The results show that,the decadal,annual and seasonal sunshine durations in Akto County showed a decreasing trend in the past 50 years,while the decrease of seasonally climatic tendencies are unlike,the most decreasing range is in summer and the least is in spring.Correlation analysis concluded that precipitation is the main factor affecting the Akto County sunshine hours change.