资源环境科技发展态势分析平台

Drainage networks emerge due to the movement of sediment driven by climatic and tectonic forcings. Previous observations revealed the dependence of drainage density (D-d) on climatic factors such as mean annual precipitation (MAP). Specifically, it has been observed in intermediate climate (similar to 175 mm < MAP < 700 mm) that D-d decreases with increasing MAP. This declining trend has been argued to be attributed to biotic activity, that is, the dominance of vegetation growth over runoff erosive force. Using high-resolution topographic data from a physical experiment, we show that increasing rainfall may result in decreasing D-d even in the absence of biotic activity. Increasing rainfall rate results in narrower and less variable bifurcation angle and relatively longer links. The response of the evolving network in terms of bifurcation angle continues beyond the time when D-d has reached a new stable value, indicating that the network's topological response is relatively slower than the geomorphic response.