Abstract:

In order to estimate the region’s future evolution trend of precipitation and the development of watershed management planning and the rational exploitation and utilization of water resources to provide a theoretical basis, using climate trend analysis, wavelet analysis and M-K mutation testing methods, such as analysis of Xilinhot 50 years rainfall from 1961 to 2010, the multi-time scale variations. The results showed that: weakly decreasing trend of annual precipitation, summer and autumn showed a decreasing trend, especially in summer, but summer precipitation for the largest contribution to annual precipitation; spring and winter, although weakly increasing trend, and in the spring than in winter. The monthly rainfall above normal and below normal fluctuations showed a trend, which was the largest decrease in August, followed by July. Historical annual precipitation maxima was in 1974, the minimum in 2005, and the range of 359.9 mm. Rainy period in the late 1960s-late 1970s and 1990s, the dry period in the 1960s and the 2l century. More obvious changes in precipitation time scale variations, changed in cycle changes in small scale high frequency, while in a large scale was relatively low, respectively, 2-5 years and 10 years around the cycle performance significantly. 50 years annual precipitation in 1999 was a significant change in mutation point, by the rainy period to dry period.