Snow cover over the Iberian mountains in km-scale global climate simulations: Evaluation and projected changes

Study region We focus on the four main mountain ranges of the Iberian Peninsula. In such Mediterranean mountains, complex topography and high climate variability make snowpacks a crucial natural resource, highly vulnerable to the impacts of climate change. Study focus Due to their coarse resolution, traditional climate models cannot properly represent the complexity of orographic processes. In this work, we assess the performance of the global km-scale IFS-FESOM model in simulating seasonal snow cover and projecting climate change effects in Iberian mountains. This approach provides high-quality regional information directly from global simulations, bypassing the need for traditional regional downscaling. The model is evaluated against high-resolution reanalysis-based products, satellite retrievals, and in situ observations. Furthermore, future snow cover trends are assessed under the SSP3-7.0 emission scenario. New hydrological insights for the region Despite a positive bias in snowfall days, the model successfully represents key features of the snow climatology, such as the elevation dependency, the seasonal cycle, and the mean covered area. The projection shows a marked reduction of the snow season across Iberia, with low- to mid-elevations and the southernmost ranges showing the greatest reductions. These changes are linked to reduced snowfall days, caused primarily by rising temperatures but also by decreasing precipitation. The results demonstrate that global km-scale simulations can provide physically consistent local climate projections in complex terrain as a simpler and robust alternative to traditional regionalization.