CANDYSHOP: Connecting ablation, accumulation and glacier dynamics using Hintereisferner’s ice lollipops

Glacier mass balance is a key indicator of climate change, yet current measurement methods face fundamental discrepancies. The glaciological method captures the direct climatic signal over seasons or years at the glacier surface, while the geodetic method, based on digital elevation models, integrates volume change over the glacier and therefore smooths short-term variability. The two methods are physically linked through ice flux divergence, which cancels out over entire glaciers but varies locally. Beyond the global glacier records needed for sea-level rise assessments, high-resolution data are vital for understanding glacier dynamics and glacier–atmosphere interactions. Advances in long-range terrestrial laser scanning (TLS) and deep learning now offer new opportunities to bridge this gap.

CANDYSHOP proposes a new method based on the ice lollipop: a mass balance stake with a reflective object on top that can be tracked in three dimensions by a permanent and automated TLS system. Our pilot study showed that near-daily glacier surface elevation and ice flux divergence can be continuously monitored without requiring repeated field visits.

We expand this approach to a network of ice lollipops distributed across Hintereisferner, capturing both local variability and spatially integrated signals. Combined with automated snow density sensors, this network enables continuous observations of ablation, accumulation and glacier dynamics. The observations are complemented by deep learning-based ice dynamics modelling, enabling us to separate processes such as ice flux divergence and surface elevation change.

CANDYSHOP therefore deploys the first observational method that directly connects the glaciological and geodetic methods at the point scale, at high spatiotemporal resolution and without extensive, labour-intensive field efforts. In a second step, we will evaluate whether discrepancies between glaciological and geodetic mass balance profiles are systematic, linking them through ice flux divergence. This will help refine the extraction of the climatic signal from glacier mass balance measurements and strengthen regional estimates.

By connecting observations across spatial and temporal scales, CANDYSHOP aims to improve our understanding of how local glacier processes relate to glacier-wide mass changes and to provide new insights into glacier dynamics.

Project leaders: 
Annelies VOORDENDAG

Project Duration: 
1 August 2026 to 31 July 2029