Shifting pattern of hook structures and impacts on storm runoff extremes under anthropogenic climate warming

Understanding the hook structure between storm runoff extremes and temperature is key to quantifying the complex response of flooding regime to anthropogenic climate warming, but its underlying mechanisms, shifting trajectories and environmental consequences are highly uncertain. Our in-situ observations suggest a spatially homogeneous negative sensitivity of relative humidity to rising temperatures, with a colder peak point temperature (Tpp) than that of precipitation and storm runoff extremes, implying that atmospheric moisture constraint plays an important but inferior role than thermodynamic drivers in extreme-temperature scaling. To probe into the complex interplay of hook structures and weather-related hazard evolution, we focus on flooding menace over China’s main catchments and project streamflow scenarios with model cascade chains combining 31 CMIP5 models, bias correction and four hydrological models. The ensemble projections confirm a severe enhancement of extremes, with involvement of the hook structure’s continuous shift towards a warmer temperature accompanying by an upward movement under future warming.