资源环境科技发展态势分析平台

Large rivers play crucial roles in determining locations of civilization, biodiversity and efflux to the oceans. The paths they take across Earth's surface vary with scale. At long‐wavelengths rivers can have simple flow paths. At smaller scales, in meanders for example, their paths change rapidly as a consequence of lithology, biota and other environmental variables. It is not straightforward to identify the scales at which river planforms are set. We overcome these issues by developing a spectral (wavelet) methodology to map flow‐directions as a function of distance and scale. This methodology allows short‐wavelength features (e.g. meanders) to be filtered from river flow‐paths. With short‐wavelength structure removed, the flow‐directions of rivers in Western USA correlate with long‐wavelength gravity anomalies suggesting control by sub‐plate support. This relationship is replicated by an ensemble of landscape evolution models. These results combined suggest that drainage at large scales, O km is set by sub‐plate support.