Decadal modelling of rainfall-runoff erosivity in the Euro-Mediterranean region using extreme precipitation indices

This paper presents and assesses the Decadal Rainfall Erosive Multiscale Model (DREMM), in which extreme precipitation data (95th percentile) are used to estimate decadal-scale rainfall-runoff erosivity values compatible with the Universal Soil Loss Equation and its revision (R)USLE. The test area was a large region including central Europe and Mediterranean countries, in which 111 decades from 88 weather stations (ranging from about 3 to 1680 m above sea level) with rain and (R)USLE rainfall-runoff erosivity data were available. The construction of the model is simplified to a location-explicit term and to the understanding that the most erosive rainfalls are those recorded during the summertime and the beginning of autumn (May-October). These precipitation events are suitable for use in spatial and temporal climate variability studies on decadal time-scales. Once parameterized to capture decadal rainfall-runoff erosivity variability over central Europe and the Mediterranean, the DREMM was run to produce spatial patterns of rainfall-runoff erosivity in Germany and Bulgaria, compared to maps from the (R)USLE approach for 1961-1990. Implications for rainfall-runoff erosivity modelling were discussed concluding that a limited number of parameters may be sufficient to represent decadal rainfall-runoff erosivity for the central European and Mediterranean region. A transferable approach is recommended by employing the DREMM to assess the spatial impact of rainfall extremes. Its use to characterize the long-term dynamics of rainfall-runoff erosivity may also be of value in climate investigation. (C) 2012 Elsevier B.V. All rights reserved.