The multi-time-scale correlations for drought–flood index to runoff and North Atlantic Oscillation in the headstreams of Tarim River, Xinjiang, China

The multi-time-scale correlations for the drought–flood index to annual runoff and North Atlantic Oscillation (NAO) in the past 50 years were analyzed by collecting monthly precipitation and annual runoff data and employing the methods of the Z index and wavelet analysis in the headstreams of the Tarim River. The following results were obtained. (1) The drought–flood index for the study area has been rising. The periodicities of the index were 4, 8, and 22 years with the periods of 4 and 8 years being significant. (2) The periodicities of annual runoff were 6, 17, and 22 years, with the 6-year period being the most significant. (3) The annual runoff of the Tarim River had significant negative correlation with the drought–flood index at multiple time-scales. The time sections of significant correlation were 2–10-year periods from the early 1970s to the late 1990s. (4) The drought–flood index had significant correlation with the NAO for periods of less than 10 years, which was negative mainly for the whole year and summer, and positive in winter. The aim of this study is to provide scientific guidance for achieving the reasonable allocation and regulation of water resources in the Tarim River Basin.