Surface Mass Balance of the Cordillera Darwin Icefield, Tierra del Fuego, Chile

The Cordillera Darwin Icefield (CDI) in Tierra del Fuego is the third-largest temperate icefield in the southern hemisphere, covering an area of 2606 km² and storing at least twice the ice volume of the European Alps. More than half of the CDI glaciers are in direct contact with proglacial lakes or fjords, making them susceptible to both climatic surface mass change and ice-dynamic adjustments. Remote sensing studies have observed important mass losses in the region over the last decades. Despite the overall glacier retreat, individual glaciers show contrasting behavior, with some maintaining stable conditions or even thickening and advances, particularly in the central and southern part of the CDI. Associating the recent developments with atmospheric changes is challenging as in-situ observations of climatic conditions and glacier mass balance are scarce due to the harsh weather conditions and the difficult accessibility of the area.

We aim for generating a first, high-resolution simulation of surface mass balance for the entire CDI over the last two decades (2000-2022). Comprising all mass gain and loss terms at the surface, the surface mass balance is ultimately tied to robust high-resolution information on the atmospheric conditions. We will employ state-of-the-art statistical downscaling of atmospheric variables, paying special attention to downscaling of precipitation and the orographic effects over the high relief terrain. Moreover, climate conditions in Southern Patagonia are characterized by strong, year-round westerly winds, leading to efficient snow drift and increased spatially heterogeneity of snow deposition.

The results of our study will enable us to analyze variations in surface mass balance across space and time in the CDI. The key objective is to reliably disentangle the climatic imprint on glacier mass loss in the Cordillera Darwin for the last two decades. This climatic attribution is unprecedented and a unique opportunity to study the effects of climate variability and change in the higher mid latitudes of the southern hemisphere. Mass budgeting with remotely sensed mass balance observations will finally allow to derive a first estimate of frontal ablation and thus ice-dynamic controls on glacier changes in the CDI.