Unraveling scale-dependent flood responses to changing climate extremes over the Tibetan Plateau

Abstract Understanding of the dynamic interplay between plateau floods and climate extremes has long been constrained by scale fragmentation in existing studies. Our multi-scale analysis unravels and interprets the scale-dependent responses of floods to changes in climate extremes across the Tibetan Plateau (TP). Extreme precipitation, temperature, and snowmelt drive the average flood day increase (0.7 d/10a) at the plateau scale, while the rise in annual maximum daily discharge (Qmax) (2.1 m³/s/10a) is modulated by extreme precipitation and drought indices. Watershed-scale analysis uncovers a distinct east-west partitioning of flood drivers, whereas river order-scale analysis reveals patterned shifts in flood drivers from main streams to tributaries. Cross-watershed analysis shows that upstream temperature changes contribute 5.3% to downstream flood frequency and 4.8% to magnitude variability via hydrological connectivity. The scale-specific disparities, shaped by the synergistic effects of watershed hydrological processes, underlying surface heterogeneity, climate factor sensitivities, and climate-cryosphere interactions, establish a framework for alpine flood attribution and predictive models.