Spatio-temporal variations of precipitation in arid and semiarid regions of China: The Yellow River basin as a case study

Daily precipitation data from 64 precipitation gauging stations within the Yellow River basin were analyzed by defining 17 precipitation indices with the aim to investigate space and time changes in precipitation characteristics. The modified Mann–Kendall trend test method was used to detect trends in the precipitation series. The influence of Interdecadal Pacific Oscillation (IPO) on the basin precipitation was also investigated. Results indicate that: (1) the Yellow River basin is dominated by decreasing precipitation and precipitation deficit may further deteriorate the shortage of water resources. The middle Yellow River basin may encounter increasingly serious shortage of water resources and higher risk of floods would be expected in the lower Yellow River basin; (2) a higher risk of droughts can be expected in spring and autumn and precipitation in winter is increasing, which imply evident seasonality and seasonal shifts of precipitation changes within the basin; (3) short-duration consecutive precipitation events are prevalent in the basin and frequency and amount of short-duration consecutive precipitation events are increasing; (4) precipitation extremes are not dominant in the Yellow River basin, except for some regions in the North China Plain and rainstorm events are generally decreasing; and (5) no evident impact of IPO on the precipitation in the Yellow River basin is found. In this case, precipitation deficit would be a major problem the basin-scale water resources management may face in the future.