ABSTRACT

Societies can be better prepared to face hydrological extremes (e.g. flash floods) by understanding the trends and variability of rainfall aggressiveness and its derivative, erosivity density (ED). Estimating extended time series of ED is, however, scientifically challenging because of the paucity of long-term high-resolution pluviometric observations. This research presents the longest ED time series reconstruction (1701–2019) in northwest Italy (Piedmont region) to date, which is analysed to identify damaging hydrological periods. With this aim, we developed a model consistent with a sample (1981–2015) of detailed novel Revised Universal Soil Loss Erosion-based high-resolution data and documentary hydrological extreme records. The modelled data show a noticeable rising trend in ED from 1897 onwards, together with an increase of extreme values for return periods of 10 and 50 years, consistent with the Clausius‐Clapeyron scaling of extreme rainfall. We also suggest the North Atlantic Oscillation and Atlantic Multidecadal Oscillation may be associated with rainfall extremes in Piedmont.

摘要

通过了解降雨侵袭性及其衍生的侵蚀密度 (ED) 的趋势和变化，社会可以更好地准备应对极端水文事件（例如山洪暴发）。然而，由于缺乏长期高分辨率雨量观测，估计 ED 的扩展时间序列在科学上具有挑战性。本研究展示了迄今为止意大利西北部（皮埃蒙特地区）最长的 ED 时间序列重建（1701-2019），并对其进行分析以确定破坏性水文时期。为此，我们开发了一个模型，该模型与详细新颖的基于修订版普遍土壤流失侵蚀的高分辨率数据和文献水文极端记录的样本（1981-2015 年）一致。建模数据显示，从 1897 年开始，ED 有明显的上升趋势，以及 10 年和 50 年重现期的极值增加，这与极端降雨量的克劳修斯-克拉珀龙标度一致。我们还认为北大西洋涛动和大西洋多年代际涛动可能与皮埃蒙特的极端降雨有关。