Mapping monthly rainfall erosivity in Europe.

Cristiano Ballabio,Kazimierz Banasik,Preben Olsen,Mónika Lakatos,Silas Michaelides,Nazzareno Diodato,Christine Alewell,Alexandru Dumitrescu,Sašo Petan,Andreas Klik,Katrin Meusburger,Jonathan Spinoni,Melita Perčec Tadić,Svetla Rousseva,Pasquale Borrelli,Julia Kostalova,Juha Aalto,Panos Panagos,A Rymszewicz ,M Janeček ,Santiago Beguerı́a

doi:10.1016/j.scitotenv.2016.11.123

Abstract

Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part of Britain and Ireland) in May and the highest values are registered during summer months. Starting from September, R-factor has a decreasing trend. The mean rainfall erosivity in summer is almost 4 times higher (315 MJ mm ha− 1 h− 1) compared to winter (87 MJ mm ha− 1 h− 1).The Cubist model has been selected among various statistical models to perform the spatial interpolation due to its excellent performance, ability to model non-linearity and interpretability. The monthly prediction is an order more difficult than the annual one as it is limited by the number of covariates and, for consistency, the sum of all months has to be close to annual erosivity. The performance of the Cubist models proved to be generally high, resulting in R2 values between 0.40 and 0.64 in cross-validation. The obtained months show an increasing trend of erosivity occurring from winter to summer starting from western to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in different seasons of the year.

Highlights

Rainfall is essential for plant development, biomass and agriculture but it is the driving force for water erosion processes through detachment of soil particles and formation of surface runoff (Nyssen et al, 2005)
Rainfall is the main driver for soil erosion by water and the relationship between rainfall and sediment yield is given by rainfall erosivity (Yang and Yu, 2015)
The spatial models' prediction of monthly European R-factors was satisfactory in terms of R2 and root mean squared error (RMSE)

Summary

Introduction

Rainfall is essential for plant development, biomass and agriculture but it is the driving force for water erosion processes through detachment of soil particles and formation of surface runoff (Nyssen et al, 2005). Soil erosion prediction is of crucial importance for appropriate land management and soil use (Oliveira et al, 2013). Soil erosion models play an important role in soil erosion predictions and among them the USLE (Wischmeier and Smith, 1978) and RUSLE (Renard et al, 1997) are the most widely used. Among the soil erosion risk factors rainfall erosivity and land cover/ management are considered the most dynamic factors to change during the year. The rainfall erosivity variability affects agriculture, forestry, hydrology, water management, and ecosystem services. An assessment of monthly erosivity over Europe is still missing

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Conclusion