Precipitation in Aibi lake basin of Xinjiang from 1961 to 2008.

The annual,decadal variations and anomalous years of the annual and seasonal mean precipitation were investigated in the context of the monthly data at 6 meteorological and hydrological stations in Aibi Lake basin of Xinjiang from 1961 to 2008. The results indicated:⑴ The annual precipitation showed an increasing trend and the rate was 6.72 mm/10a during recent 48 years,moreover,the increasing trend was apparent in each season with a rate of (1.43～4.88)mm/10a,max in summer and min in autumn. ⑵ In the 1960s and 1970s,both annual precipitation and seasonal precipitation were less,especially in winter. In the 1980s,the annual,spring and summer precipitations were normal,while the autumn and winter precipitations were more. So far from the 1990s,the annual,spring,summer and winter precipitations were more. ⑶ The abrupt year was detected in 1968. The annual precipitation showed a slightly descending trend and the rate was 2.01 mm/10a from 1961 to 1986,however,the increasing trend existed in recent 22 years with a rate of 8.52 mm/10a. ⑷ The change of annual precipitation had interannual quasi-fluctuations of 3 years from 1961 to 1979,7 years from 1980 to 1997,and 3 years in the remaining years again.