Future trend analysis of precipitation in the Haihe River Basin based on a method combining wavelet and rescaled range analyses

Abstract

Climate change has become an increasingly dominant environmental issue which has been attracting more and more attention in recent years. It is necessary to determine the cycle and trend of annual precipitation in the Haihe River Basin in the context of climate change because it is the largest river system in northern China. A combined method of rescaled range analysis and wavelet analysis is applied to identify the cycle and trend in annual precipitation based on data from 12 weather stations in the Haihe River Basin. The results of wavelet analysis show that the 12 weather stations all have the long main cycles of 35-38 years and the medium-length cycles of 22-25 years. Datong, Yuanping, Shijiazhuang, Taiyuan, Anyang, and Huimin stations have the short-length cycles of 9-11 years. The results of re-scaled range analysis show that all of the Hurst exponents are greater than 0.5, which indicates that the future trend of annual precipitation will very likely follow the historical trend. Therefore, nine stations will have the downward trends, and other stations will have the upward trends in the future, according to the analysis of the historical trends by the method of wavelet analysis.