Characteristics of precipitation and temperature in the Daqing River Basin

The statistical characteristics of precipitation and temperature in the Daqing River Basin from 1980 to 2015 are analyzed, including the analysis of the homogeneity, trend, mutation and periodicity. Among them, the analysis of homogeneity is based on the method of cumulative value. The trend analysis adopts the methods of moving average, M-K test and R/S. M-K test is also used for the mutation analysis. The wavelet transform is used in the periodic analysis to draw the contour of real part and modulus of precipitation and temperature, as well as the map of the wavelet variance and the main period trend. The results show that the precipitation in the Daqing River Basin from 1980 to 2015 is uniform and has a significant upward trend, and has a sudden change in 2008. As for the periodicity, there are three kinds of periodic changes in 22-32 years, 8-16 years and 3-7 years. In the 22-32 year scale, there are two quasi oscillations of the dry and wet alternation, and four quasi oscillations in the 8-16 year scale. In the graph of the wavelet variance, the peak corresponds to the time scale of 28 years, which indicates that the oscillation of 28 years is the strongest, which is the first main period of precipitation change. From 1980 to 2015, the temperature in the Daqing River Basin is also uniform, and has an obvious upward trend, and has a sudden change in 1992. As for the periodicity, there are three kinds of periodic change, 5-10 years, 14-20 years and 25-32 years, respectively. In the 25-32 year scale, there are two quasi oscillations of dry and wet alternation, and three quasi oscillations in the 14-20 year scale. There are three obvious peaks in the map of wavelet variance, which correspond to the time scales of 28 years, 18 years and 8 years in turn.