Aaron Cremona

Last Name

Cremona

First Name

Aaron

ORCID

0000-0003-2553-903X

Organisational unit

09599 - Farinotti, Daniel / Farinotti, Daniel

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Publications 1 - 4 of 4

Subglacial cavity collapses on Swiss glaciers: Spatiotemporal distribution and mass loss contribution
Hösli, Leo; Ogier, Christophe; Bauder, Andreas; et al. (2025)
Journal of Glaciology
Glacier collapse features, linked to subglacial cavities, are increasingly common on retreating Alpine glaciers. These features are hypothesized to result from glacier downwasting and subsurface ablation processes but the understanding regarding their distribution, formation and contribution to glacier mass loss remains limited. We present a Swiss-wide inventory of 223 collapse features observed over the past 50 years, revealing a sharp increase in their occurrence since the early 2000s. Using high-resolution digital elevation models, we derive a relationship between collapse feature area and ice ablation and estimate the Swiss-wide contribution of collapse features to glacier mass loss to be $19.8\times 10<^>6\,\text{m}<^>3$ of ice between 1971 and 2023. Based on extensive observations at Rhonegletscher, including surface displacement, ground-penetrating radar and drone-based elevation models, we quantify subsurface ablation rates of up to 27 cm d-1 and provide a detailed description of the collapse processes. We propose that glacier downwasting, enhanced energy supply through subglacial conduits and locally increased basal melt are key components to subglacial cavity growth. Our results highlight the importance of collapse features in the ongoing retreat of Alpine glaciers, stressing the need for further research to understand their formation and long-term implications for glacier dynamics under climate change.
European heat waves 2022: contribution to extreme glacier melt in Switzerland inferred from automated ablation readings
Cremona, Aaron; Huss, Matthias; Landmann, Johannes Marian; et al. (2023)
The Cryosphere
Accelerating glacier melt rates were observed during the last decades. Substantial ice loss occurs particularly during heat waves that are expected to intensify in the future. Because measuring and modelling glacier mass balance on a daily scale remains challenging, short-term mass balance variations, including extreme melt events, are poorly captured. Here, we present a novel approach based on computer-vision techniques for automatically determining daily mass balance variations at the local scale. The approach is based on the automated recognition of colour-taped ablation stakes from camera images and is tested and validated at six stations installed on three Alpine glaciers during the summers of 2019-2022. Our approach produces daily mass balance with an uncertainty of ±0.81 cm w.e. d-1, which is about half of the accuracy obtained from visual readouts. The automatically retrieved daily mass balances at the six sites were compared to average daily mass balances over the last decade derived from seasonal in situ observations to detect and assess extreme melt events. This allows analysing the impact that the summer heat waves which occurred in 2022 had on glacier melt. Our results indicate 23 d with extreme melt, showing a strong correspondence between the heat wave periods and extreme melt events. The combination of below-average winter snowfall and a suite of summer heat waves led to unprecedented glacier mass loss. The Switzerland-wide glacier storage change during the 25 d of heat waves in 2022 is estimated as 1.27 ± 0.10 km3 of water, corresponding to 35 % of the overall glacier mass loss during that summer. The same 25 d of heat waves caused a glacier mass loss that corresponds to 56 % of the average mass loss experienced over the entire melt season during the summers 2010-2020, demonstrating the relevance of heat waves for seasonal melt.
Constraining sub-seasonal glacier mass balance in the Swiss Alps using Sentinel-2-derived snow-cover observations
Cremona, Aaron; Huss, Matthias; Landmann, Johannes M.; et al. (2025)
Journal of Glaciology
The severe ice losses observed for European glaciers in recent years have increased the interest in monitoring short-term glacier changes. Here, we present a method for constraining modelled glacier mass balance at the sub-seasonal scale and apply it to ten selected glaciers in the Swiss Alps over the period 2015-23. The method relies on observations of the snow-covered area fraction (SCAF) retrieved from Sentinel-2 imagery and long-term mean glacier mass balances. The additional information provided by the SCAF observations is shown to improve winter mass balance estimates by 22% on average over the study sites and by up to 70% in individual cases. Our approach exhibits good performance, with a mean absolute deviation (MAD) to the observed seasonal mass balances of 0.28 m w.e. and an MAD to the observed SCAFs of 6%. The results highlight the importance of accurately constraining winter accumulation when aiming to reproduce the evolution of glacier mass balance over the melt season and to better separate accumulation and ablation components. Since our method relies on remotely sensed observations and avoids the need for in situ measurements, we conclude that it holds potential for regional-scale glacier monitoring.
Monitoring Short-Term Glacier Mass Balance Variations
Cremona, Aaron (2025)
VAW-Mitteilungen
Glaciers worldwide are melting at unprecedented rates, driven by ever-increasing climate change. Glacier melting affects society and economy on several fronts, impacting natural hazards, water supply and hydropower production, tourism, and sea level rise. Aiming to understand and quantify these impacts has driven substantial developments related to glacier mass balance monitoring, relying on direct measurements, remote sensing observations, and mathematical models. Despite significant advancements in the field, monitoring short-term mass balance variations, i.e. at the daily to weekly scale, is hindered by the lack of observational data and thus only sparsely explored.

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Aaron Cremona

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