Abstract ID: 28.7291 | Accepted as Poster | Poster | 2025-02-27 13:00 - 14:30 | Ágnes‐Heller‐Haus/Small Lecture Room

At the start of the 21st century, the glaciers of the European Alps have been subject to dramatic changes as a result of sustained atmospheric warming. In high-altitude areas, the thermal degradation of cold firn and ice to a temperate state has severe implications, including: the irreversible loss of paleoclimatic data; the destabilisation of cold-based hanging glaciers; and an acceleration in glacial mass loss due to a decrease in firn meltwater retention. Unfortunately, our knowledge of the physical transition between these thermal regimes is limited and current model parameterisations may not be fully applicable for transitioning firn. In the Monte Rosa massif of the Swiss/Italian Alps, an extensive fieldwork campaign was carried out at the turn of the century by the ALPCLIM project measuring firn temperatures across a vast spatial domain. Therefore, there exists an invaluable opportunity to conduct a repeat measurement campaign in this region to investigate firn facie development over the proceeding 25 years. Furthermore, the establishment of a permanent weather station at the Capanna Margherita (4,560 m a.s.l.) from 2003, provides a representative hourly meteorological time series to force coupled energy balance firn models. Our preliminary results, using a heavily modified version of the Coupled Snow and Ice Model in Python (COSIPY), reveal a dramatic reduction in the spatial extent of cold firn with a marked increase in surface melt driving this change. Our project envisions further developing the model with more sophisticated means to simulate preferential percolation – a process found to be pivotal during our previous research in influencing firn hydrology and the retainment of energy released from meltwater refreezing. The realisation of our proposed fieldwork campaign will provide a robust set of data with which our results can be validated and hopefully support the development of new models.