Landscape texture set to scale

Abstract

Why, in many landscapes, does ridge–valley spacing show such regularity? The combination of high-resolution data and an elegant model offers a solution to this long-standing puzzle, for some cases at least. Seen from above, it's clear that in many hilly landscapes the ridges and valleys appear uniformly spaced. Current physically based models of landscape evolution produce realistic looking topography, but cannot predict the 'wavelength' typical of evenly spaced ridges and valleys in natural landscapes. Taylor Perron and colleagues use equations of mass conservation and sediment transport to derive a characteristic length scale that is directly proportional to the ridge–valley wavelength in models of landform evolution and at five field study sites across the United States, including Nappa Valley in California and Point of the Mountain in Utah. The findings provide a quantitative explanation for one of the most widely observed characteristics of landscapes and suggest that valley spacing records the effects of material properties and climate on erosional processes.