1.2 Approach and Scope
Here, we investigate how spatio-temporal changes in precipitation may influence erosion and topography of mountain landscapes using the stream power model (SPM). First, we show how simple spatial gradients in rainfall, resembling typical orographic precipitation patterns (i.e., increasing or decreasing downstream; herein referred to as bottom-heavy, and top-heavy, respectively), influence river profile form at steady state in one dimension. Next, we use a quasi-two-dimensional numerical model to simulate the response of a transverse river network to a change in rainfall pattern, which we compare to better-understood spatially uniform changes in rainfall. Finally, we discuss some implications for studies set in mountain landscapes. A comprehensive analysis of the co-evolution of orographic rainfall patterns and topography is beyond the scope of this paper. Instead, we focus on characterizing the controls on landscape response to imposed changes in rainfall patterns, highlighting where expectations differ from uniform changes in rainfall, and implications of those differences.