Characteristics of Drought-Flood Abrupt Alternation in Mihe River Basin from 1976 to 2020
Based on the daily rainfall data from 1976 to 2020 at 13 rainfall stations in the Mihe River Basin,using the long-cycle drought-flood abrupt alternation index(LDFAL)and short-cycle drought-flood abrupt alternation index(SDFAL),the spatial and temporal distribu-tion characteristics of drought-flood abrupt alternation in the Mihe River Basin were analyzed by the Mann-Kendall trend test and Mann-Ken-dall mutation test,the moving T test,the rescaled range analysis(R/S)method,the wavelet analysis and the inverse distance interpolation method.The results show that there are 18 drought-flood abrupt alternation in the Mihe River Basin during the long-cycle of June-September within 45 years,and the LDFAL shows a decreasing trend,which indicates that the phenomenon of"drought to flood"will dominate in the future,while the SDFAL shows an increasing trend in June-July and August-September,which indicates that the phenomenon of"drought to flood"will be dominated in the future.SDFAL shows an increasing trend in June-July and August-September,indicating that the phenomenon of"flood to drought"will dominate in the future;and a decreasing trend in July-August,indicating that the phenomenon of"drought to flood"will dominate in the future.There is no sudden change in the LDFAL and the intensity of the long-cycle drought-flood abrupt alterna-tion,and the SDFAL only change in June-July 2007,while the intensity of the short-cycle drought-flood abrupt alternation changes in June-July 2007 and July-August 2005,respectively.There is an 11-year main cycle for the long-cycle drought-flood abrupt alternation phenomena,while the short-cycle of June-July,July-August and August-September has 34-year,64-year and 43-year main cycles of change,respectively.
drought-flood abrupt alternationtrend analysistemporal and spatial variationMihe River Basin
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