Abstract. Currently, the anthropogenic disturbances to the biogeochemical cycles remain unquantified due to the poor representation of lateral fluxes of carbon and nutrients in Earth System Models (ESMs) that couple the terrestrial and ocean systems. Soil redistribution plays an important role in the transport of carbon and nutrients between terrestrial ecosystems, however, quantification of soil redistribution and its effects on the global biogeochemical cycles is missing. This study aims at developing new tools and methods to represent soil redistribution on a global scale, and contribute to the quantification of anthropogenic disturbances to the biogeochemical cycles. We present a new large-scale coarse resolution sediment budget model that is compatible with ESMs. This model can simulate spatial patterns and long-term trends in soil redistribution in floodplains and on hillslope, resulting from external forces such as climate and land use change. We applied this model on the Rhine catchment using climate and land cover data from the Max Planck Institute Earth System Model (MPI-ESM) for the last millennium (850-2005 AD). Validation is done using observed Holocene sediment storage data and observed scaling relations between sediment storage and catchment area from the Rhine catchment. We found that the model reproduces the spatial distribution of floodplain sediment storage and the scaling relationships for floodplains and hillslopes as found in observations. The exponents of the scaling relationships can be modified by changing the spatial distribution of erosion or by changing the residence time for floodplains. However, the main feature of the scaling behavior, which is that sediment storage in floodplains increases stronger with catchment area than sediment stored on hillslopes, is not changed. Based on this we argue that the scaling behavior is an emergent feature of the model and mainly dependent on the underlying topography. Additionally, we identified that land use change explains most of the temporal variability in sediment storage for the last millennium in the Rhine catchment.
Modelling long-term, large-scale sediment storage using a simple sediment budget approach