Under the threat of ongoing global warming, predictions concerning how much temperatures will rise and precipitation will change are undergoing continual improvement, but the spatial distribution of predicted changes and their impacts on Earth-surface processes, notably erosion and sedimentation, are subject to great uncertainty. Such processes have immediate consequences for people living along alluvial or “transport-limited” rivers, which constitute the majority of rivers on Earth, yet their evolution in response to external forcing conditions is not well understood.
In the GyroSCoPe project, funded by an ERC Consolidator grant, we will address these knowledge gaps through an approach that focuses on how periodic changes in climate affect Earth-surface processes. Because the frequency of each forcing period likely dictates how far downstream in alluvial channels impacts are felt, it should be possible to decipher the impacts of individual periodic forcings in the geomorphic record, i.e., through alluvial fans and fluvial terraces. To do this, we will apply novel tools to decipher erosion histories in mountainous regions (glaciated and non-glaciated), and we will investigate downstream alluvial fans and fluvial terraces in the context of a recently developed model for the evolution of gravel-bedded rivers. Our new data will allow us to interpret the impact of periodic climate forcing on hillslope erosion rates, track how this sediment propagates across landscapes through alluvial rivers, and thus provide a wealth of data that can be used to calibrate landscape-evolution and alluvial-channel models. This improved understanding of the impacts of the magnitude and frequency of periodic forcing on erosion rates and sediment transport through rivers will in turn enable: