Comparison of estuarine sediment record with modelled rates of sediment supply from a western European catchment since 1500

2020

npj Clim Atmos Sci

Erosive storms constitute a major natural hazard. They are frequently a source of erosional processes impacting the natural landscape with considerable economic consequences. Understanding the aggressiveness of storms (or rainfall erosivity) is essential for the awareness of environmental hazards as well as for knowledge of how to potentially control them. Reconstructing historical changes in rainfall erosivity is challenging as it requires continuous time-series of short-term rainfall events. Here, we present the first homogeneous environmental (1500–2019 CE) record, with the annual resolution, of storm aggressiveness for the Po River region, northern Italy, which is to date also the longest such time-series of erosivity in the world. To generate the annual erosivity time-series, we developed a model consistent with a sample (for 1981–2015 CE) of detailed Revised Universal Soil Loss Erosion-based data obtained for the study region. The modelled data show a noticeable descending trend in rainfall erosivity together with a limited inter-annual variability until ~1708, followed by a slowly increasing erosivity trend. This trend has continued until the present day, along with a larger inter-annual variability, likely associated with an increased occurrence of short-term, cyclone-related, extreme rainfall events. These findings call for the need of strengthening the environmental support capacity of the Po River landscape and beyond in the face of predicted future changing erosive storm patterns.

Section: Numerical and Categorical Dependent Variablesmentioning

confidence: 99%

“…annual resolution or lower) and space (i.e. non-locally calibrated) 66 . For that, parsimonious models can be used since they overcome the limitations imposed by detailed models, which are data demanding and inapplicable to historical times 67 .…”

Section: Introductionmentioning

confidence: 99%

Historical predictability of rainfall erosivity: a reconstruction for monitoring extremes over Northern Italy (1500–2019)

Diodato¹,

2020

npj Clim Atmos Sci

“…Such measurements are generally not available before the modern instrumental period (digital measurements first systematically began in the 1980s; Diodato, 2004), and the only possibility to obtain past rainfall erosivity data is that offered by parsimonious modeling approaches, which use proxy (indirect) inputs from long-term storms and floods (Diodato et al, 2017a). Modeling approaches using low-resolution precipitation data-both temporal (annual or finer resolution) and spatial (not locally calibrated, Poirier et al, 2016)-and documentary records of extreme weather events allow for long-term reconstructions (Diodato et al, 2008). To assess the historical documentary data about the damaging hydrological events that occurred in the ARB over the 1000-2019 CE period, we have used meteorological anomalies such as storms and floods, and their variability.…”

Section: Introductionmentioning

confidence: 99%

Climate Patterns in the World’s Longest History of Storm-Erosivity: The Arno River Basin, Italy, 1000–2019 CE

Diodato¹,

2021

Front. Earth Sci.

Rainfall erosivity causes considerable environmental damage by driving soil loss. However, the long-term evolution of erosive forcing (over centennial to millennial time-scales) remains essentially unknown. Using a rainfall erosivity model (REMARB), this study simulates the variability of rainfall erosivity in Arno River Basin (ARB), Italy, a Mediterranean fluvial basin, for the period 1000–2019 CE resulting in the world’s longest time-series of erosivity. The annual estimates show a noticeable and increasing variability of rainfall erosivity during the Little Ice Age (∼1250–1849), especially after c. 1490, until the end of 18th century. During this cold period, erosive forcing reached ∼1600 MJ mm hm−2 h−1 yr−1 once every four years, and ∼3000 MJ mm hm−2 h−1 yr−1 once every 20 years. The extremes of rainfall erosivity (the 98th percentile) followed a similar increasing trend, with an acceleration of the hydrological hazard (erosivity per unit of rainfall) during the 20th century. The comparison of REMARB output with the sediment yield of the basin (1951–2010) confirmed the model’s ability to predict geomorphological effects in the ARB. Thus, our methodology could be applied to simulate erosivity in environmentally similar basins. A relationship has been identified between the Atlantic Multidecadal Variation and erosivity patterns, suggesting a role of North Atlantic circulation dynamics on the hydrology of central Italy’s fluvial basins.

“…Modelling approaches making use of low-resolution precipitation data and documentary records of extreme weather events provide a means to derive long-term reconstructions. When satisfactory instrumental input data are unavailable, information from historical documentary sources can be used to support low-resolution storm-erosivity estimates 37 , both in time (i.e., with annual resolution or finer) and space (i.e., non-locally calibrated) 38 . In this study, we developed a modelling approach of the temporal fluctuations of storm-erosivity across the Mediterranean Central Area (MedCA), which is the most exposed region in southern Europe to aggressive rainfall (Fig.…”

Section: Introductionmentioning

confidence: 99%

Fingerprint of climate change in precipitation aggressiveness across the central Mediterranean (Italian) area

Diodato¹,

2020

Sci Rep

Rainfall erosivity and its derivative, erosivity density (ED, i.e., the erosivity per unit of rain), is a main driver of considerable environmental damages and economic losses worldwide. This study is the first to investigate the interannual variability, and return periods, of both rainfall erosivity and ED over the Mediterranean for the period 1680–2019. By capturing the relationship between seasonal rainfall, its variability, and recorded hydrological extremes in documentary data consistent with a sample (1981–2015) of detailed Revised Universal Soil Loss Erosion-based data, we show a noticeable decreasing trend of rainfall erosivity since about 1838. However, the 30-year return period of ED values indicates a positive long-term trend, in tandem with the resurgence of very wet days (> 95th percentile) and the erosive activity of rains during the past two decades. A possible fingerprint of recent warming is the occurrence of prolonged wet spells in apparently more erratic and unexpected ways.