Cirques, peaks, and precipitation patterns in the Swiss Alps: Connections among climate, glacial erosion, and topography

Abstract

Glacial erosion, a process influenced by climate, has been implicated in limiting the relief of mountain ranges. However, climate itself is sensitive to large-scale topography, suggesting that climate, topography, and glacial processes form a coupled system. Large spatial gradients in precipitation exist in the southern Swiss Alps, allowing us to study this coupling in a region of climate variability. More than 500 cirques were identified, and neighboring peaks were found to co-vary in elevation with cirque floors ( R 2 0.64). Cirque headwall relief does not vary with precipitation or cirque floor altitude. These relationships confirm the hypothesis that cirque formation restricts peak altitudes via slope processes that limit the relief of cirque headwalls. We compared the position of the regional equilibrium line altitude (ELA) estimated from modern climate to a surface defined by the cirque floors. The modern ELA and cirque floor surfaces are similar in shape, illustrating the impact of spatial variability in precipitation on glacial processes and topography. Precipitation variability in this region is partially dictated by large-scale topography. Therefore, precipitation patterns, glacial process domains, and topography must evolve together.