The degradation and detection of environmental signals in sediment transport systems.

Autogenic processes contribute noise to sediment transport systems that can degrade or mask externally derived environmental signals and hinder our ability to reconstruct past environmental signals from landscapes and strata. To explore this further, we measure efflux from a physical rice pile to ascertain the temporal structure of autogenic noise, and how this influences the degradation and detection of environmental signals. Our results reveal a tripartite temporal spectral structure segmented at two key autogenic time scales. The shorter autogenic time scale set limits on environmental signal degradation, while the longer autogenic time scale sets limits on environmental signal detection. This work establishes a framework that can be used to explore how autogenic processes interact with external environmental signals in field-scale systems to influence their detectability. We anticipate that the temporal structure and associated time scales identified will arise from autogenic processes in numerous sediment transport systems.