资源环境科技发展态势分析平台

Orographic impact on extreme sub‐daily precipitation is critical for risk management but remains insufficiently understood due to complicated atmosphere‐orography interactions and large uncertainties. We investigate the problem adopting a framework able to reduce uncertainties and isolate the systematic interaction of Mediterranean cyclones with a regular orographic barrier. The average decrease with elevation reported for hourly extremes is found enhanced at sub‐hourly durations. Tail heaviness of 10‐minute intensities is negligibly affected by orography, suggesting self‐similarity of the distributions at the convective scale. Orography decreases the tail heaviness at longer durations, with a maximum impact around hourly scales. These observations are explained by an orographically‐induced redistribution of precipitation towards stratiform‐like processes, and by the succession of convective cores in multi‐hour extremes. Our results imply a breaking of scale‐invariance at sub‐hourly durations, with important implications for natural hazards management in mountainous areas.