Where in the World Are Vegetation Patterns Controlled by Hillslope Water Dynamics?

Abstract

AbstractSome recent land surface models can explicitly represent land surface process and focus more on sub‐grid terrestrial features. Many studies have involved the analysis of how hillslope water dynamics determine vegetation patterns and shape ecologically and hydrologically important landscapes, such as desert riparian and waterlogged areas. However, the global locations and abundance of hillslope‐dominated landscapes remain unclear. To address this knowledge gap, we propose a globally applicable method that employs high‐resolution elevation, hydrography, and land cover data to concisely resolve explicit land cover heterogeneity for the mapping of hillslope‐dominated landscapes. First, we aggregate pixels into unit catchments to represent topography‐based hydrological units, and then vertically discretize them into height bands to approximate the hillslope profile. The dominant land cover type in each height band is determined, and the uphill land cover transition is analyzed to identify hillslope‐dominated landscapes. The results indicate that hillslope‐dominated landscapes are distributed extensively worldwide in diverse climate zones. Notably, some landscapes, including gallery forests in northeastern Russia and desert riparian in the Horn of Africa, are newly revealed. Furthermore, the proposed strategy enables more accurate representation of explicit land cover heterogeneity than does the simple downscaling of a rectangular grid from larger to smaller units, revealing its capability to concisely resolve land cover heterogeneity in land surface modeling with relatively high accuracy. Overall, we present the extensive global distribution of landscapes shaped by hillslope water dynamics, underscoring the importance of the explicit resolution of heterogeneity in land surface modeling.