Assessment of monthly and seasonal average precipitation by Convection Permitting Climate Models across an Alpine transect

Precipitation in the Alpine region of north-eastern Italy plays a critical role in shaping hydrological regimes, ecosystems, and human activities, yet its variability across complex terrain remains a major challenge for climate modeling. This thesis assesses the performance of convection-permitting climate models (CPMs) in reproducing monthly and seasonal average precipitation along an Alpine transect, with particular emphasis on elevation-dependent processes. Using a dense network of 174 rain gauges, observed precipitation was compared against simulations from the collocations of multiple CPMs and their ensemble median. Statistical diagnostics included correlation coefficients, relative bias, fractional root mean square error (FRMSE), and regression analyses linking normalized precipitation to elevation. Results demonstrate that CPMs provide added value over coarser regional climate models by explicitly resolving convective processes and capturing orographic enhancement. Seasonal and monthly evaluations reveal consistent elevation-dependent biases, with stronger correlations in summer and fall compared to winter and spring. Regression slopes confirm the influence of elevation on precipitation distribution, though the strength of this relationship varies by season and month. Overall, the findings underscore the importance of high-resolution CPMs for hydrological risk assessment in mountainous regions. By quantifying model skill across temporal scales and elevations, this study provides critical insights into the reliability of CPMs for climate diagnostics and risk management. The results contribute to advancing precipitation modeling in complex terrain and support the development of more robust strategies for water and geological risk engineering.