Abstract: Based on the precipitation data of 10 meteorological stations in the Mu Us Sandy Area from 1961 to 2016, the mutation detections of annual precipitation were tested by the Mann-Kendall method and t test, the periodic variation were discussed by the Morlet wavelet analysis method. Precipitation change characteristics on four time scales of year, season, month and day were analyzed according to precipitation isolines zone, and the differences of seasonal precipitation were analyzed in two time periods. Results showed that the spatial characteristics of annual precipitation in the Mu Us Sandy Area were obviously different, the eastern sub-region showed an upward trend while the central and western sub-regions showed a downward trend, however, the change trend was not significant and there were no mutations. Distribution of precipitation within a year is uneven, and the dry and wet seasons are distinct. The precipitation is mainly concentrated during the period of May-and September, the summer and autumn precipitation accounts for a dominant proportion of the annual precipitation. Moreover, the precipitation on four time scales of year, season, month and day have gradient decreasing change from east to west. A self-similar structure with multiple time scales existed in the process of inter-annual precipitation change. In the recent 26 years, the precipitation in winter and spring increased markedly, but the fluctuation range of precipitation was less than that in previous 30 years.

Key words: Mu Us Sandy Area, mutation detection, wavelet analysis, multi-time scales