Asymmetric impacts of urbanization on precipitation in the Ordos Plateau urban agglomeration

Understanding how urbanization intensifies precipitation, especially in water-sensitive arid regions, is critical for climate adaptation. This study investigates the nonlinear and scale-dependent responses of precipitation to urbanization in the Ordos Plateau, China, an ecologically fragile arid region experiencing rapid urban expansion. We parameterized urbanization intensity and precipitation amplification to quantify their relationship across different quantiles (τ) and time scales using a mixed-effects nonlinear quantile regression model. This approach allowed us to control for site-specific variability and isolate the generalizable urbanization effect. Our results reveal a robust urbanization intensity-dependent precipitation enhancement. On average, across the time scales considered, a tenfold increase in urbanization intensity amplifies extreme precipitation (τ = 0.99) by approximately 0.590 units, which is about 4.6 times greater than its effect on light precipitation (τ = 0.01). Furthermore, the marginal contribution of urbanization to precipitation amplification diminishes with increasing urbanization levels but remains persistently higher for extreme events. Crucially, these nonlinear effects are more pronounced at monthly and seasonal scales than at the annual scale, underscoring a heightened vulnerability to short-term extremes. These findings reveal that urban expansion in arid and semi-arid regions disproportionately exacerbates extreme precipitation risks. It is therefore suggested that urban planning, water resource management, and disaster prevention policies integrate this nonlinear, urbanization intensity–dependent relationship to enhance climate resilience.