Université de Fribourg

Change detection of bare-ice albedo in the Swiss Alps

Naegeli, Kathrin ; Huss, Matthias ; Hoelzle, Martin

In: The Cryosphere, 2019, vol. 13, no. 1, p. 397–412

Albedo feedback is an important driver of glacier melt over bare-ice surfaces. Light- absorbing impurities strongly enhance glacier melt rates but their abundance, composition and variations in space and time are subject to considerable uncertainties and ongoing scientific debates. In this study, we assess the temporal evolution of shortwave broadband albedo derived from 15 end-of-summer...

Université de Fribourg

Cross-comparison of albedo products for glacier surfaces derived from airborne and satellite (sentinel-2 and landsat 8) optical data

Naegeli, Kathrin ; Damm, Alexander ; Huss, Matthias ; Wulf, Hendrik ; Schaepman, Michael ; Hoelzle, Martin

In: Remote Sensing, 2017, vol. 9, no. 2, p. 110

Surface albedo partitions the amount of energy received by glacier surfaces from shortwave fluxes and modulates the energy available for melt processes. The ice- albedo feedback, influenced by the contamination of bare-ice surfaces with light- absorbing impurities, plays a major role in the melting of mountain glaciers in a warming climate. However, little is known about the spatial and...

Université de Fribourg

Imaging spectroscopy to assess the composition of ice surface materials and their impact on glacier mass balance

Naegeli, Kathrin ; Damm, Alexander ; Huss, Matthias ; Schaepman, Michael ; Hoelzle, Martin

In: Remote Sensing of Environment, 2015, vol. 168, p. 388–402

Glacier surfaces are not only composed of ice or snow but are heterogeneous mixtures of different materials. The occurrence and dynamics of light-absorbing impurities affect ice surface characteristics and strongly influence glacier melt processes. However, our understanding of the spatial distribution of impurities and their impact on ice surface characteristics and the glacier's energy budget...

Université de Fribourg

Dendritic subglacial drainage systems in cold glaciers formed by cut-and-closure processes

Naegeli, Kathrin ; Lovell, Harold ; Zemp, Michael ; Benn, Douglas I.

In: Geografiska Annaler: Series A, Physical Geography, 2014, vol. 96, no. 4, p. 591–608

The routing and storage of meltwater and the configuration of drainage systems in glaciers exert a profound influence on glacier behaviour. However, little is known about the hydrological systems of cold glaciers, which form a significant proportion of the total glacier population in the climate sensitive region of the High Arctic. Using glacio-speleological techniques, we obtained direct access...