Analysis of drought and flood alternation and its driving factors in the Yangtze River Basin under climate change

The spatial and temporal characteristics of global precipitation have changed significantly under climate change, increasing the difficulty of solving water security problems. Therefore, understanding changes in global precipitation is of great importance to comprehend and solve water security problems. This study analyzed the characteristics of drought and flood alternation in the Yangtze River Basin (YRB) based on precipitation data, and explored the driving forces of drought and flood alternation by combining relevant meteorological factors (i.e., temperature [Tem], relative humidity [Rh], wind speed [Win], and actual evaporation [ETa]) and teleconnection indices (i.e., Nino 3.4, Pacific Decadal Oscillation [PDO], Southern Oscillation Indices [SOI], North Pacific Index [NPI], and Atlantic Multi-decadal Oscillation [AMO]). The main conclusions are as follows: (1) The spatial and temporal characteristics of precipitation in the sub-basins of the YRB varied widely, with significant annual precipitation trends ranging from −5 to 9 mm/year (p < 0.05). The maximum temporal difference in the rainy season reached 1–2 months; (2) The mutations of precipitation in the period of pre-flood (PP), precipitation in the period of post-flood (PN), and long-cycle drought-flood abrupt transition index (LDFAI) in sub-basins of the YRB (e.g., Mintuojiang River Basin [MRB], Wujiang River Basin [WRB], Dongting Lake Basin [DLRB], Yichang-Hukou Reach [YC-HK], Downstream of Hukou [DHKRB], and Taihu Lake Basin [TLRB]) were prominent from 2001 to 2011; and (3) both the single factor (i.e., meteorological factors or teleconnection index) and multiple factors (i.e., meteorological factors and teleconnection index) influenced the LDFAI of each sub-basin in the YRB. Related research is important and useful for studying dry–wet changes and water security issues in the YRB.