Development of a Meteorological and Hydrological Coupling Index for Droughts and Floods along the Yangtze River Valley of China

摘要

To comprehensively investigate characteristics of summer droughts and floods in the Yangtze River valley,a meteorological and hydrological coupling index(MHCI)was developed using meteorological and hydrological data.The results indicate that:(1)in representing drought/flood information for the Yangtze River valley,the MHCI can reflect composite features of precipitation and hydrological observations;(2)comprehensive analysis of the interannual phase diference of the precipitation and hydrological indices is important to recognize and predict annual drought/flood events along the valley;the hydrological index contributes more strongly to nonlinear and continuity features that indicate transition from long-term drought to flood conditions;(3)time series of the MHCI from 1960–2009 are very efective and sensitive in reflecting annual drought/flood characteristics,i.e.there is more rainfall or typical flooding in the valley when the MHCI is positive,and vice versa;and(4)verification of the MHCI indicates that there is significant correlation between precipitation and hydrologic responses in the valley during summer;the correlation coefcient was found to reach 0.82,exceeding the 0.001 significance level.