Change Trend and Prediction for Future of Visibility in Kashgar City

Based on meteorological data of Kashgar city from 1973to 2010and trend analysis,Mann-Kendall method and classification method,the interannual,seasonal and decadal changes of visibility of Kashgar city were analyzed,and the future trend was predicted by R/S analysis method in this paper.Results showed that the visibility of Kashgar city has consistently come down and the annual average visibility and four seasonal visibility reached the minimum in early 21century;the days of second level visibility had significantly increased.The days of fourth and fifth level occurred in the 1970s only and the days of first and third level visibility had significantly declined and the days of first and third level visibility only occurred in 1970s;the days of second level visibility will increase consistently and the days of third level visibility will decrease consistently and the days of first level visibility will be transformed from consistent decrease to sustained increase;the visibility of four seasons will be worse in the following several years.