Application of a minimal glacier model to Hansbreen, Svalbard 1Institute for Marine and Atmospheric research Utrecht, Utrecht University, P.O. Box 80005, 3508 TA Utrecht, The Netherlands
03 Jan 2011
2Faculty of Earth Sciences, University of Silesia, ul. Bedzinska 60, 41-200 Sosnowiec, Poland
Received: 20 Jun 2010 – Published in The Cryosphere Discuss.: 13 Jul 2010Abstract. Hansbreen is a well studied tidewater glacier in the southwestern part of
Svalbard, currently about 16 km long. Since the end of the 19th century
it has been retreating over a distance of 2.7 km. In this paper the global
dynamics of Hansbreen are studied with a minimal glacier model, in which the
ice mechanics are strongly parameterised and a simple law for iceberg
calving is used. The model is calibrated by reconstructing a climate history
in such a way that observed and simulated glacier length match. In addition,
the calving law is tuned to reproduce the observed mean calving flux for the
Revised: 24 Nov 2010 – Accepted: 10 Dec 2010 – Published: 03 Jan 2011
Equilibrium states are studied for a wide range of values of the equilibrium
line altitude. The dynamics of the glacier are strongly nonlinear. The
height-mass balance feedback and the water depth-calving flux feedback
give rise to cusp catastrophes in the system.
For the present climatic conditions Hansbreen cannot survive. Depending on
the imposed climate change scenario, in AD 2100 Hansbreen is predicted to
have a length between 10 and 12 km. The corresponding decrease in ice volume
(relative to the volume in AD 2000) is 45 to 65%.
Finally the late-Holocene history of Hansbreen is considered. We quote
evidence from dated peat samples that Hansbreen did not exist during the
Holocene Climatic Optimum. We speculate that at the end of the mid-Holocene
Climatic Optimum Hansbreen could advance because the glacier bed was at
least 50 m higher than today, and because the tributary glaciers on the
western side may have supplied a significant amount of mass to the main
stream. The excavation of the overdeepening and the formation of the shoal
at the glacier terminus probably took place during the Little Ice Age.
Citation: Oerlemans, J., Jania, J., and Kolondra, L.: Application of a minimal glacier model to Hansbreen, Svalbard, The Cryosphere, 5, 1-11, doi:10.5194/tc-5-1-2011, 2011.