"Modelling soil erosion under rainfall-cell-patterns using weather-radar at regional scale". SESSION 133441: Soil Erosion and Land Degradation: methods, observations and perspectives. Centennial of the IUSS Florence – Italy May 19 – 21, 2024.
Water erosion is one of the most widespread forms of soil degradation and it is expected to increase as an effect of global change, especially due to the amplified frequency of extreme and localised rainfall events. Focusing on the Mediterranean region, where these phenomena produce the most catastrophic erosion, this research aims to model soil erosion focusing on rainfall spatial distribution using precipitations as detected by weather ground-radar upon an analysis of rainfall-cell patterns at regional scale (Tuscany, Italy)
Precipitations were elaborated by adopting a kriging method processing CAPPI (Constant Altitude Plan Position Indicator) reflectivity and rain gauges rainfall with an External Drift Kriging (KED) over a 30' time-step frames and 5’ conditional merging images based on elaborations made available by DPCN (Italian National Civil Protection Department). Soil erosion was modelled using the platform based on the soil erosion/landscape evolution model LandSoil under Python coding simulating runoff combining a cinematic wave using St.Venant equations with a conceptual “bucket” model for infiltration, and a two-level sediment redistribution process for rill and inter-rillerosion on a sediment concentration protocol.
Soil erosion was simulated over a selection of rainfall events from the last ten years. Results are illustrated through a combined representation of factors that considers: 1) The land surface affected by the storm (i.e., rainfall-cellsubjected to runoff), 2) The involved rainfall energy and erosion rate of the processes, 3) The sediment yielddelivered over the erosive event. Such approach, applied to seasonal analysis, opens-up to a methodology foranalysing the spatial extent of the rainfall and the erosive effects at ground. Drifts in erosion could be also detected by the use of long-terms rainfall series and return-time of the erosive events, useful to inspect the evolution of the processes due to climate change.
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