How does rainfall temporal variability shape landscape evolution?

Rainfall intensity and total amounts are often used to estimate erosion, yet landscapes frequently respond in non-linear ways, especially when erosion thresholds are crossed. With climate change expected to intensify hydroclimatic extremes, understanding the role of rainfall variability has become increasingly important. Using a combination of numerical models, in this work we explored how rainfall temporal variability affects catchment morphology and sediment dynamics over centennial timescales. Multiple rainfall scenarios were generated using a stochastic rainfall generator model and were used to assess catchment geomorphic response through the CAESAR-Lisflood landscape evolution model.

In this study, we showed that more variable rainfall leads to higher net sediment discharge, increased erosion, and greater sediment deposition. The response was particularly strong in arid regions, where catchments were more sensitive to rainfall fluctuations, and in systems with coarser sediment grains, which amplified erosion signals. We also derived a power-law relationship linking changes in rainfall temporal variability to changes in sediment discharge, consistent across simulations and supported by long-term observational data.

These findings highlight the need to explicitly account for local rainfall variability when estimating future soil erosion and downstream sediment delivery under climate change.

Che out the manuscript at this link!