Process-based modelling of the climatic forcing of fluvial sediment flux: some examples and a discussion of optimal model complexity

During the complex and highly dynamic climate of the Late Quaternary, precipitation and temperatures were highly variable and generally did not change synchronously. Reconstructed fluvial sedimentological response to this climatic forcing was previously shown to be complex. This response can be understood only by accounting for all the relevant catchment processes. This paper reviews a number of simple numerical models that aim to enhance our understanding of the role of different processes in this climate-sedimentology system. The applicability of these models depends on the scale of the models involved, the required input data and the way that parameters are estimated. Simple process-based models perform best on Quaternary timescales because their data needs are low and parameters can be interpreted in physical terms, which enables an a priori estimation. Process-based models of fluvial dynamics may provide a methodology for the understanding of the mechanisms responsible for the dynamics of sediment flux to basins.