Understanding elevation-dependent warming in the Alps through high-resolution surface energy balance analysis

This study investigates elevation-dependent warming (EDW) in the Alps, focusing on Berchtesgaden National Park, Germany, to provide insights into the drivers of warming patterns and their spatial variability.
EDW refers to the variation in warming rates across altitude, often characterized by intensified warming trends at higher elevations. This phenomenon has significant implications for mountainous and downstream ecosystems and water resources. While multiple factors contributing to EDW have been discussed in the literature – such as snow-albedo feedbacks and the increased sensitivity of cold, dry regions to climate change – the roles of soil interactions and topography remain underexplored.

Our research uses high-resolution spatial data and long-term temperature records to uncover how topography, soil properties and surface energy dynamics contribute to EDW. We utilize data from HISTALP, a homogenized observational dataset for the Greater Alpine Region, to examine the relationship between warming trends and topographic factors. Within the national park, 23 long-term stations monitor meteorological variables. Additionally, three temporary stations spanning altitudes from 617 to 1930 m measure surface energy balance components to capture elevation-dependent and small-scale effects.

Preliminary findings indicate that EDW is influenced by factors beyond altitude. Historical data (1910–2010) reveal significant warming across altitudes in the Greater Alpine Region, with rates of 0.4–2.4 K per century. Higher elevations generally experience stronger warming, except in winter, when mid-elevation bands (500–1000 m) warm the most. Slope orientation significantly affects warming rates, with north-facing slopes showing amplified trends. Ongoing research aims to develop a statistical model incorporating topography, vegetation and soil properties to map warming trends across the Alps.
Ground heat flux analysis reveals spatial variations potentially influenced by soil depth and moisture retention at different altitudes. Integrating these observations with simulations from the GEOtop hydrological model will provide spatially detailed and novel insights into relevant land surface processes.