Université de Fribourg

Monitoring rock glacier kinematics with satellite synthetic aperture radar

Strozzi, Tazio ; Caduff, Rafael ; Jones, Nina ; Barboux, Chloé ; Delaloye, Reynald ; Bodin, Xavier ; Kääb, Andreas ; Mätzler, Eva ; Schrott, Lothar

In: Remote Sensing, 2020, vol. 12, no. 3, p. 559

Active rock glaciers represent the best visual expression of mountain permafrost that can be mapped and monitored directly using remotely sensed data. Active rock glaciers are bodies that consist of a perennially frozen ice/rock mixture and express a distinct flow-like morphology indicating downslope permafrost creep movement. Annual rates of motion have ranged from a few millimeters to...

Université de Fribourg

Recent glacier and lake changes in High Mountain Asia and their relation to precipitation changes

Treichler, Désirée ; Kääb, Andreas ; Salzmann, Nadine ; Xu, Chong-Yu

In: The Cryosphere, 2019, vol. 13, no. 11, p. 2977–3005

We present an updated, spatially resolved estimate of 2003–2008 glacier surface elevation changes for the entire region of High Mountain Asia (HMA) from ICESat laser altimetry data. The results reveal a diverse pattern that is caused by spatially greatly varying glacier sensitivity, in particular to precipitation availability and changes. We introduce a spatially resolved zonation where...

Université de Fribourg

Northern Hemisphere permafrost map based on TTOP modelling for 2000–2016 at 1 km2 scale

Obu, Jaroslav ; Westermann, Sebastian ; Bartsch, Annett ; Berdnikov, Nikolai ; Christiansen, Hanne H. ; Dashtseren, Avirmed ; Delaloye, Reynald ; Elberling, Bo ; Etzelmüller, Bernd ; Kholodov, Alexander ; Khomutov, Artem ; Kääb, Andreas ; Leibman, Marina O. ; Lewkowicz, Antoni G. ; Panda, Santosh K. ; Romanovskyh, Vladimir ; Wayk, Robert G. ; Westergaard-Nielsen, Andreas ; Wu, Tonghua ; Yamkhin, Jambaljav ; Zou, Defu

In: Earth-Science Reviews, 2019, vol. 193, p. 299–316

Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To estimate permafrost distribution at a hemispheric scale, we employ an equilibrium state model for the temperature at the top of the permafrost (TTOP model) for the 2000–2016...

Université de Fribourg

Multi-decadal mass balance series of three Kyrgyz glaciers inferred from modelling constrained with repeated snow line observations

Barandun, Martina ; Huss, Matthias ; Usubaliev, Ryskul ; Azisov, Erlan ; Berthier, Etienne ; Kääb, Andreas ; Bolch, Tobias ; Hoelzle, Martin

In: The Cryosphere, 2018, vol. 12, no. 6, p. 1899–1919

Glacier surface mass balance observations in the Tien Shan and Pamir are relatively sparse and often discontinuous. Nevertheless, glaciers are one of the most important components of the high-mountain cryosphere in the region as they strongly influence water availability in the arid, continental and intensely populated downstream areas. This study provides reliable and continuous surface mass...

Université de Fribourg

Mass-balance reconstruction for Glacier No. 354, Tien Shan, from 2003 to 2014

Kronenberg, Marlene ; Barandun, Martina ; Hoelzle, Martin ; Huss, Matthias ; Farinotti, Daniel ; Azisov, Erlan ; Usubaliev, Ryskul ; Gafurov, Abror ; Petrakov, Dmitry ; Kääb, Andreas

In: Annals of Glaciology, 2016, vol. 57, no. 71, p. 92–102

This study presents a reconstruction of the seasonal mass balance of Glacier No. 354, located in the Akshiirak range, Kyrgyzstan, from 2003 to 2014. We use a distributed accumulation and temperature-index melt model driven by daily air temperature and precipitation from a nearby meteorological station. The model is calibrated with in situ measurements of the annual mass balance collected from...

Université de Fribourg

Combined observations of rock mass movements using satellite SAR interferometry, differential GPS, airborne digital photogrammetry, and airborne photography interpretation

Strozzi, Tazio ; Delaloye, Reynald ; Kääb, Andreas ; Ambrosi, Christian ; Perruchoud, Eric ; Wegmüller, Urs

In: Journal of Geophysical Research, 2010, p. F01014

Recent global warming, through the related retreat of mountain glaciers, causes a growing number of different slope instabilities requiring accurate and cost-effective monitoring. We investigate the potential of combined remote sensing observations from satellite and airborne microwave and optical sensors for an efficient survey of mountainous ground displacements. The evolution of a paraglacial...