The response of meteorological drought to extreme climate in the water-receiving area of the Tao river diversion project in China

Against the backdrop of increasing global extreme climate events, the water-receiving area of the Tao River Diversion Project in China frequently experiences drought disasters. In view of this, this study uses the meteorological drought index (SPEI) and 12 extreme climate indicators to analyze drought and extreme climate changes and their effects on drought. The results show that SPEI12 presents a slow but persistent downward trend, with 1988 as the turning point. Drought frequency exhibited a spatial pattern of being lower in the northwest and higher in the southeast. Additionally, droughts occurred more frequently but were of shorter duration. The summer days (SU) and warm days and warm nights (TX 90p, TN 90p) increased significantly. Although extreme precipitation events increased, the magnitude of change was not significant and thus could not effectively counteract the drought trend. Annual total precipitation (PRCPTOT), cold days (TX10p) and summer days (SU) are the main driving factors of meteorological drought, and their contribution rates are 23.35, 18.93 and 14.75% respectively. Annual total precipitation (PRCPTOT) and summer days (SU) have linear relationship with meteorological drought, and extreme climate indexes such as warm spell duration index (WSDI) and warm nights (TN90p) have nonlinear changes. Especially, the consecutive wet days (CWD) has a significant nonlinear change, when less than 8.58 days will lead to wetting, more than 8.58 days will lead to drought. In response to pressures from a warmer and drier future climate, the agricultural sector can build adaptive capacity. This can be achieved through the adjustment of planting structures, the promotion of water-saving technologies, and the incorporation of machine learning-derived thresholds into drought monitoring systems to enhance their early warning capabilities.