Future rainfall erosivity derived from large-scale climate models — methods and scenarios for a humid region

The global greenhouse effect is expected not only to increase mean global temperatures, but also to influence characteristics of rainfall. Increased variability of precipitation and a higher amount of erosive rainfall in Middle Europe may also increase soil erosion. In this study the modified Fournier's index is used to derive future rainfall erosivity values by the use of predicted monthly rainfall amounts for elaborating an index in accordance with the universal soil loss equation. The fundamental idea is the significant correlation between this index and the erosivity factor R. Future monthly precipitation data which are required for those calculations were produced by a general circulation model and adjusted to finer scales by expanded downscaling. The results suggest an increase of rainfall erosivity for eight stations in North Rhine-Westphalia (Germany).