Swiss Earth Observatory Network (SEON) 

The Swiss Earth Observatory Network (SEON) is a competence centre to monitor status and functioning of Swiss ecosystems in a changing environment. An increasing demand for natural resources impacts important biotic and physical processes within the Earth system and causes complex interactions within terrestrial ecosystems. SEON pursues a holistic Earth system science approach to assess environmental change impacts on ecosystem functioning and considers complex feedback mechanisms between the Earth spheres, including the human impact.

The contribution of the University of Fribourg focuses on the use of albedo products from the air-borne multispectral imagery for glacier melt modelling and process understanding. In particular, the reasons for the presently observed darkening of alpine glacier surfaces, i.e. its components and drivers, will be investigated on several Swiss glaciers.


Research aims/sciences questions:
(1) What is the surface albedo of a glacier and how is its distribution?
(2) What kind of components (mineral, organic) are present on a glacier surface and how are they altering the glacier surface albedo?
(3) How does the surface albedo of glaciers change over different time-scales?
(4) How is the glacier surface albedo altering glacier melt processes?


Methodology of the project: airborne imaging spectroscopy (Airborne Prism EXperiment – APEX), satellite remote sensing, field spectroscopy, portable, in-situ albedo measurements, automatic weather station, direct glaciological mass balance measurements


Study area: Glacier de la Plaine Morte (Valais), Findelengletscher (Valais)

  • Exemplary results
    Surface classification of Glacier de la Plaine Morte 

    based on the APEX scene taken on the 31th of August 2013

  • Publications
    • Naegeli, K., Damm, A., Huss, M., Schaepman, M. and Hoelzle, M. (2015). Imaging spectroscopy to assess the composition of ice surface materials and their impact on glacier mass balance. Remote Sensing of Environment, 168, 388-402. doi:10.1016/j.rse.2015.07.006
    • Naegeli, K., Huss, M., Hoelzle, M. (2019) Change detection of bare-ice albedo in the Swiss Alps. The Cryosphere 13, 397-412.
    • Naegeli, K., Huss, M. (2017) Sensitivity of mountain glacier mass balance to changes in bare-ice albedo. Annals of Glaciology.
    • Naegeli, K., Damm, A., Huss, M., Wulf, H., Schaepman, M., Hoelzle, M. (2017) Cross-comparison of albedo products for glacier surfaces derived from airborne and satellite (Sentinel-2 & Landsat 8) optical data. Remote Sensing 9.
    • Hoelzle, M., Naegeli, K., (2017) From bright white glaciers to dark dusty ice, Open Access Government. Adjacent Government, pp. 240-241.

Duration: 2013-2016

Funded by: State Secretariat for Education, Research and Innovation (SBF) and ETH-Board as a Cooperation and Innovation Project (KIP) initiated by the Swiss University Conference (SUK)

Collaborators: M. Schaepmann, Kathrin Naegeli (PhD student), Matthias Huss (PostDoc), Martin Hoelzle (Prof.)

Partner(s): University of Zurich, ETH Zurich, EAWAG, EMPA, Agroscope, Paul Scherrer Institute (PSI) (Prof. Dr. Margit Schwikowski, PhD student Anna del Farra)




Prof. Martin Hoelzle

Department of Geosciences

University of Fribourg
Chemin du Musée 4

CH–1700 Fribourg

   +41 26 300 90 21