The role of climate in landscape evolution: a coupled model of erosion and precipitation

The primary controls on landscape evolution are the tectonic and climatic processes that work to uplift and erode a landscape. These processes work together to produce, erode, and transport sediment in steep, mountainous watersheds. Quantifying the tectonic and climatic controls acting on a landscape and their role in sediment production is thus vital to our understanding of the temporal and spatial evolution of orogens and their sedimentary record. To gain important quantitative insight into what climatic properties influence landscape evolution, we implement a numerical modeling approach. We investigate climate-landscape interactions by coupling a landscape evolution model, Landlab, with a high-resolution climate model, WRF. The Andes act as the climatic setting for this study, due to the variation in climate along the length of the orogen and serve as a natural laboratory to test tectonic and climatic controls on erosion. Discharge is quantified across the landscape with the WRF-Hydro model. Both discharge and topography are passed between Landlab and WRF, allowing for a feedback relationship to form between topography and precipitation. We will present our model runs that result from an asynchronous model coupling approach. We explore five domains that span the length of the orogen at 10° intervals from 0° to 40°S. Preliminary climate results show a 25 fold increase in annual precipitation and a 140 fold increase in annual channel discharge between experiments. We will present results showing how these differences in climate across the orogen change the erosional processes and landscape form of each of the domains. This work provides a necessary next step in landscape evolution modeling by using an actively evolving climate to model real precipitation dynamics. This next step allows for modeling more accurate representations of precipitation, through the development of an orogen, that will work to better constrain the role climate plays in landscape evolution. Investigating this role is critical because the sedimentary archive is often used to interpret orogenic processes and unravel the history of an orogen. This work will provide an improved understanding of the importance of climate in the sedimentary record and insights into the co-evolution of climate and topography during the lifespan of an orogen.